PARASYMPATHOLYTICS

 

INTRODUCTION:  Drugs that block the action of Acetylcholine are known by a number of names, including anticholinergics, cholinergic blockers, muscarinic antagonists, and parasympatholytics.  Although the term anticholinergic is most commonly used, the most accurate term for this class of drugs is muscarinic antagonists, because at therapeutic doses, these drugs are selective for Ach muscarinic receptors and thus have little effect on Ach nicotinic receptors.

PHARMACODYNAMICS:  Anticholinergics act by competing with Ach for binding muscarinic receptors. When anticholinergics occupy these receptors, no response is generated at the neuroeffector organs. Suppressing the effects of Ach causes symptoms of sympathetic nervous system activation to predominate. Most therapeutic uses of the anticholinergics are predictable extensions of their parasympathetic-blocking actions: dilation of the pupils, increase in heart rate, drying of secretions, and relaxation of the bronchi.

THERAPEUTIC USES:  1. GI disorders:  These agents decrease the secretion of gastric acid in peptic ulcer disease. They also slow intestinal motility and may be useful for reducing the cramping and diarrhea associated with irritable bowel syndrome. 

2. Ophthalmic procedures:  Anticholinergics may be used to cause mydriasis or cycloplegia during eye procedures.

3. Cardiac rhythm abnormalities:  Anticholinergics can be used to accelerate the heart rate in patients experiencing bradycardia.

4. Preanesthesia:  Combined with other agents, anticholinergics can decrease excessive respiratory secretions and reverse the bradycardia caused by general anesthetics.

5. Asthma:  A few agents, such as ipratropium, are useful in treating asthma, because of their ability to dilate the bronchi.

6. Overactive bladder:  Anticholinergics treat urinary retention and incontinence.

7. Degenerative nervous system application:  Anticholinergics are used to treat patients who have Parkinson’s disease and whose main symptom is tremor. The prototype drug, atropine, is used for several additional medical conditions due to its effective muscarinic receptor blockade. These applications include reversal of adverse muscarinic effects and treatment of cholinergic agent poisoning, including that caused by overdose of bethanechol, cholinesterase inhibitors, or accidental ingestion of certain types of mushrooms or organophosphate pesticides.

 

RELATED;

1.  ACETYLCHOLINE

2.  CHOLINOMIMETICS

3.  GENERATION OF A NERVE IMPULSE

4.  DIVISIONS OF THE CENTRAL NERVOUS SYSTEM

5.  ATROPINE

REFERENCES

IMIPRAMINE

 

Therapeutic Class: Antidepressant; treatment of nocturnal enuresis in children

Pharmacologic Class: Tricyclic antidepressant

ACTIONS AND USES: Imipramine blocks the re-uptake of serotonin and norepinephrine into nerve terminals. It is used mainly for major depression, although it is occasionally used for the treatment of nocturnal enuresis (bed wetting) in children. It may also be prescribed for a number of unlabeled uses, including intractable pain, anxiety disorders, and withdrawal syndromes from alcohol and cocaine. Therapeutic effectiveness may not occur for 2 or more weeks.

ADMINISTRATION ALERTS: Paradoxical diaphoresis can be a side effect of TCAs; therefore, diaphoresis may not be a reliable indicator of other disease states such as hypoglycemia.

Imipramine causes anticholinergic effects and may potentiate effects of anticholinergic drugs administered during surgery. Do not discontinue abruptly because rebound dysphoria, irritability, or sleeplessness may occur. Pregnancy category C.

ADVERSE EFFECTS: Side effects include sedation, drowsiness, blurred vision, dry mouth, and cardiovascular symptoms such as dysrhythmias, heart block, and extreme hypertension. Agents that mimic the action of norepinephrine or serotonin should be avoided because imipramine inhibits their metabolism and may produce toxicity. Some patients may experience photosensitivity and hypersensitivity to tricyclic drugs.

Warning: Antidepressants increase the risk of suicidal thinking and behavior, especially in children, adolescents, and young adults with major depressive disorder and other psychiatric disorders. This drug is not approved for use in pediatric patients. 

Contraindications: This drug should not be used in cases of acute recovery after MI, defects in bundle-branch conduction, narrow-angle glaucoma, and severe renal or hepatic impairment. Patients should not use this drug within 14 days of discontinuing MAOIs. 

INTERACTIONS: Drug–Drug: Concurrent use of other CNS depressants, including alcohol, may cause sedation. Cimetidine may inhibit the metabolism of imipramine, leading to increased serum levels and possible toxicity. Imipramine may reverse the antihypertensive effects of clonidine and potentiate CNS depression. Use of oral contraceptives may increase or decrease imipramine levels. Disulfiram may lead to delirium and tachycardia. Antithyroid agents may produce agranulocytosis. Phenothiazines cause increased anticholinergic and sedative effects. Sympathomimetics may result in cardiac toxicity. Methylphenidate or cimetidine may increase the effects of imipramine and cause toxicity. Phenytoin is less effective when taken with imipramine. MAOIs may result in neuroleptic malignant syndrome.

RELATED;

1.  DEPRESSION

2.  PHARMACOLOGY AND THERAPEUTICS

REFERENCES

DRUG METABOLISM

Introduction:  Metabolism, also called biotransformation, is the process of chemically converting a drug to a form that is usually more easily removed from the body. Metabolism involves complex biochemical pathways and reactions that alter drugs, nutrients, vitamins, and minerals. The liver is the primary site of drug metabolism, although the kidneys and cells of the intestinal tract also have high metabolic rates. Medications undergo many types of biochemical reactions as they pass through the liver, including hydrolysis, oxidation, and reduction.

Microsomal enzyme systems:  During metabolism, the addition of side chains, known as conjugates, makes drugs more water soluble and more easily excreted by the kidneys. Most metabolism in the liver is accomplished by the hepatic microsomal enzyme system. This enzyme complex is sometimes called the P-450 system, named after cytochrome P-450 (CYP-450), which is a key component of the system. The cytochrome P450 enzyme system

Enzyme induction and the role of prodrugs:  As they relate to pharmacotherapy, the primary actions of the hepatic microsomal enzymes are to inactivate drugs and accelerate their excretion. In some cases, however, metabolism can produce a chemical alteration that makes the resulting molecule more active than the original. For example, the narcotic analgesic codeine undergoes biotransformation to morphine, which has significantly greater ability to relieve pain. In fact, some agents, known as prodrugs, have no pharmacologic activity unless they are first metabolized to their active form by the body. Examples of prodrugs include benazepril and, proinsulin and losartan. Changes in the function of the hepatic microsomal enzymes can significantly affect drug metabolism. A few drugs have the ability to increase metabolic activity in the liver, a process called enzyme induction. For example, phenobarbital causes the liver to synthesize more microsomal enzymes. By doing so, phenobarbital increases the rate of its own metabolism as well as that of other drugs metabolized in the liver. In these patients, higher doses of medication may be required to achieve the optimum therapeutic effect. 

Considerations for liver functioning states:  Certain patients have decreased hepatic metabolic activity, which may alter drug action. Hepatic enzyme activity is generally reduced in infants and elderly patients; therefore, pediatric and geriatric patients are more sensitive to drug therapy than middle-age patients. Patients with severe liver damage, such as that caused by cirrhosis, will require reductions in drug dosage because of the decreased metabolic activity. Certain genetic disorders have been recognized in which patients lack specific metabolic enzymes; drug dosages in these patients must be adjusted accordingly. Metabolism has a number of additional therapeutic consequences.  

The roles of fast-pass effect:  For example, drugs absorbed after oral administration cross directly into the hepatic portal circulation, which carries blood to the liver before it is distributed to other body tissues. Thus, as blood passes through the liver circulation, some drugs can be completely metabolized to an inactive form before they ever reach the general circulation. This first-pass effect is an important mechanism, since a large number of oral drugs are rendered inactive by hepatic metabolic reactions. Alternative routes of delivery that bypass the first-pass effect (e.g., sublingual, rectal, or parenteral routes) may need consideration for these drugs. 

RELATED;

1.  ABSORPTION  

2.  PHARMACOKINETICS

REFERENCES

DRUG ABSORPTION

 

Introduction: Absorption is a process involving the movement of a substance from its site of administration, across body membranes, to circulating fluids. Drugs may be absorbed across the skin and associated mucous membranes, or they may move across membranes that line the gastrointestinal (GI) or respiratory tract. Most drugs, with the exception of a few topical medications, intestinal anti-infectives, and some radiologic contrast agents, must be absorbed to produce an effect. Absorption is the primary pharmacokinetic factor determining the length of time it takes a drug to produce its effect. Pharmacokinetics

In order for a drug to be absorbed it must dissolve. The rate of dissolution determines how quickly the drug disintegrates and disperses into simpler forms; therefore, drug formulation is an important factor of bioavailability. Bioavailability

In general, the more rapid the dissolution, the faster the drug absorption and the faster the onset of drug action. For example, famotidine administered as an orally disintegrating tablet dissolves within seconds and after being swallowed is delivered to the stomach where it blocks acid secretion from the stomach, thereby treating conditions of excessive acid secretion. Pepticulcer disease: Histamine H2 receptor blockers

At the other extreme some drugs have shown good clinical response as slowly dissolving drugs such as liothyronine sodium (T3) and thyroxine (T4) administered for resolution of hypothyroid symptoms. In some instances it is advantageous for a drug to disperse rapidly. In other cases, it is better for the drug to be released slowly where the effects are more prolonged for positive therapeutic benefit. Absorption is conditional on many factors. Drugs in elixir or syrup formulations are absorbed faster than tablets or capsules. Drugs administered in high doses are generally absorbed more quickly and have a more rapid onset of action than those given in low concentrations. The speed of digestive motility, surface area, pH, lipid solubility, exposure to enzymes in the digestive tract, and blood flow to the site of drug administration also affect absorption. Because drugs administered IV directly enter the bloodstream, absorption to the tissues after the infusion is very rapid. IM medications take longer to absorb. Drug distribution

Other factors that influence the absorption of medications include the following: Drug formulation and dose, Size of the drug molecule, Surface area of the absorptive site, Digestive motility or blood flow, Lipid solubility, Degree of ionization, Acidity or alkalinity (pH), Interactions with food and other medications. The degree of ionization of a drug also affects its absorption. A drug’s ability to become ionized depends on the surrounding pH. Aspirin provides an excellent example of the effects of ionization on absorption. In the acid environment of the stomach, aspirin is in its non-ionized form and thus readily absorbed and distributed by the bloodstream. As aspirin enters the alkaline environment of the small intestine, however, it becomes ionized. In its ionized form, aspirin is not as likely to be absorbed and distributed to target cells.

Unlike acidic drugs, medications that are weakly basic are in their nonionized form in an alkaline environment; therefore, basic drugs are absorbed and distributed better in alkaline environments such as in the small intestine. The pH of the local environment directly influences drug absorption through its ability to ionize the drug.

Drug–drug or food–drug interactions may influence absorption. Many examples of these interactions have been discovered. For example, administering tetracyclines with food or drugs containing calcium, iron, or magnesium can significantly delay absorption of the antibiotic.  High-fat meals can slow stomach motility significantly and delay the absorption of oral medications taken with the meal. Dietary supplements may also affect absorption.

RELATED;

1.  DRUG DISTRIBUTION  

2.  PHARMACOKINETICS

3.  PHARMACOLOGY AND THERAPEUTICS

REFERENCES

ANTIBACTERIAL PROPERTIES OF GOLDENSEAL

 

INTRODUCTION:  Goldenseal (Hydrastis canadensis) was once a common plant found in woods in the eastern and midwestern United States. Native Americans used the root for a variety of medicinal applications, including skin diseases, ulcers, and gonorrhea. Recent uses include the treatment of colds and other respiratory tract infections, infectious diarrhea, eye infections, vaginitis, wounds, canker sores, and cancer.

Goldenseal was once reported to mask the appearance of drugs in the urine of patients wanting to hide drug abuse but this claim has since been proved false. The roots and leaves of goldenseal are dried and are available as capsules, tablets, salves, and tinctures. Two of the active ingredients in goldenseal are berberine and hydrastine, which are reported to have antibacterial properties.

When used topically or locally, goldenseal is claimed to be of value in treating bacterial and fungal skin infections and oral conditions such as gingivitis and thrush. As an eyewash, it can soothe inflamed eyes. Considered safe for most people, it is contraindicated in pregnancy and hypertension. Hypertension: Pregnancy and drug use

RELATED;

1.  GINSENG FOR CARDIOVASCULAR DISEASE  

2.  GARLIC FOR CARDIOVASCUAR DISEASE

REFERENCES

PHARMACOKINETICS

 

INTRODUCTION: The term pharmacokinetics is derived from the root words pharmaco, which means “medicine,” and kinetics, which means “movement or motion.” Pharmacokinetics is thus the study of drug movement throughout the body. In practical terms, it describes how the body deals with medications. Pharmacokinetics is a core subject in pharmacology, and a firm grasp of this topic allows the medical professionals to better understand and predict the actions and side effects of medications in patients. Drugs face numerous obstacles in reaching their target cells.  When we are addressing pharmacokinetic aspects of a drug, we shall be looking at its absorption from the site of injection or administration, distribution in the body tissues, metabolism and then it excretion from the body.

ABSORPTION OF DRUGS:  For most medications, the greatest barrier is crossing the many membranes that separate the drug from its target cells. A drug taken by mouth, for example, must cross the plasma membranes of the mucosal cells of the gastrointestinal tract and the capillary endothelial cells to enter the bloodstream. The plasma membrane

To leave the bloodstream, the drug must again cross capillary cells, travel through the interstitial fluid, and depending on the mechanism of action, the drug may also need to enter target cells and cellular organelles such as the nucleus, which are surrounded by additional membranes.  These are examples of just some of the barriers that a drug must successfully penetrate before it can produce a response. 

METABOLISM OF DRUGS:  While moving toward target cells and passing through the various membranes, drugs are subjected to numerous physiological processes. For medications given by the enteral route, stomach acid and digestive enzymes often act to break down the drug molecules. Enzymes in the liver and other organs may chemically change the drug molecule to make it less active.  If the drug is seen as foreign by the body, phagocytes may attempt to remove it, or an immune response may be triggered. 

DRUG EXCRETION:  The kidneys, large intestine, and other organs attempt to excrete the medication from the body. These examples illustrate pharmacokinetic processes: how the body handles medications. The many processes of pharmacokinetics are grouped into four categories: absorption, distribution, metabolism, and excretion as we have briefly seen here, and we shall be seeing in our next discussions in details.

RELATED;

1.  ROUTES OF DRUG ADMINISTRATION  

2.  BIOAVAILABILITY

3.  DYNAMICS OF DRUGS AND THE HUMAN BODY

4.  DRUG METABOLISM

5.  THE PLASMA MEMBRANE

6.  PHARMACOLOGY AND THERAPEUTICS

REFERENCES

PROCHLORPERAZINE

Therapeutic Class: Antiemetic

Pharmacologic Class: Phenothiazine antipsychotic

ACTIONS AND USES: Prochlorperazine is a phenothiazine, a class of drugs usually prescribed for psychoses. The phenothiazines are the largest group of drugs prescribed for severe nausea and vomiting, and prochlorperazine is the most frequently prescribed antiemetic in its class. Prochlorperazine acts by blocking dopamine receptors in the brain, which inhibits signals to the vomiting center in the medulla. Dopamine

As an antiemetic, it is frequently given by the rectal route, where absorption is rapid. It is also available in tablet, extended-release capsule, and IM formulations.

ADMINISTRATION ALERTS: Administer 2 hours before or after antacids and antidiarrheals. Pregnancy category C.

ADVERSE EFFECTS: Prochlorperazine produces dose-related anticholinergic side effects such as dry mouth, sedation, constipation, orthostatic hypotension, and tachycardia. When used for prolonged periods at higher doses, extrapyramidal symptoms resembling those of Parkinson's disease are a serious concern, especially in older patients.

Contraindications: This drug should not be used in patients with hypersensitivity to phenothiazines, in comatose patients, or in the presence of profound CNS depression. It is also contraindicated in children younger than age 2. Patients with narrow-angle glaucoma, bone marrow suppression, or severe hepatic or cardiac impairment should not take this drug.

INTERACTIONS: Drug-Drug: Prochlorperazine interacts with alcohol and other CNS depressants to cause additive sedation. Antacids and antidiarrheals inhibit the absorption of prochlorperazine. When taken with phenobarbital, metabolism of prochlorperazine is increased. Use with tricyclic antidepressants may produce increased anticholinergic and hypotensive effects.

RELATED;

1. NAUSEA AND VOMITING  

2. ENTERIC NERVOUS SYSTEM

3.  PHARMACOLOGY AND THERAPEUTICS

REFERENCES

ECHINACEA FOR BOOSTING THE IMMUNE SYSTEM

 

Echinacea purpurea, or purple coneflower, is a popular botanical native to the midwestern United States and central Canada. The flowers, leaves, and stems of this plant are harvested and dried. Preparations include dried powder, tincture, fluid extracts, and teas. No single ingredient seems to be responsible for the herb’s activity; a large number of potentially active chemicals have been identified from the extracts. Echinacea was used by Native Americans to treat various wounds and injuries. Wound healing

Echinacea is believed to boost the immune system by increasing phagocytosis and inhibiting the bacterial enzyme hyaluronidase. Some substances in echinacea appear to have antiviral activity; thus, the herb is sometimes taken to treat the common cold and influenza, an indication for which it has received official approval in Germany. Clinical evidence for the effects of echinacea on upper respiratory tract infections is mixed, with some studies showing no effect and others showing a beneficial effect. In general, echinacea is used as a supportive treatment for any disease involving inflammation and to enhance the immune system. Inflammation: Immunity

Side effects are rare; however, it may interfere with drugs that have immunosuppressant effects.

RELATED;

1.  PASSIVE IMMUNITY  

2.  ACTIVE IMMUNISATION  

3.  SEA VEGETABLES

REFERENCES

GRAPE SEED EXTRACT FOR HYPERTENSION

 

Grapes and grape seeds have been to maintain and improve health used for thousands of years. Their primary use has been for cardiovascular conditions such as hypertension (HTN), high blood cholesterol, and atherosclerosis, and to generally improve circulation. Hypertension: Atherosclerosis

Some claim that grape seed extract improves wound healing, prevents cancer, slows the progression of neurodegenerative diseases, and lowers the risk for the long-term consequences of diabetes. Woundhealing: Diabetes

The grape seeds, usually obtained from winemaking, are crushed and placed into tablet, capsule, or liquid forms. Typical doses are 50 to 300 mg/ day. Grape seed extract has antioxidant properties that have the potential to improve wound healing and repair cellular injury. Grape seed extract is well tolerated in most people, with the most common side effects being dry, itchy scalp; dizziness; headache; hives; indigestion; and nausea. It has few adverse effects but caution should be used if taking anticoagulant drugs because increased bleeding may result.

RELATED;

1.  ARTERIOSCLEROSIS  

2.  GARLIC  

3.  BLOOD PRESSURE CONTROL

4.  TRADITIONAL AND COMPLIMENTARY MEDICATIONS

REFERENCES

HISTAMINE H2 RECEPTOR BLOCKERS

 

INTRODUCTION: Histamine has two types of receptors: H1 and H2. Activation of H1 receptors produces the classic symptoms of inflammation and allergy, whereas the H2 receptors are responsible for increasing acid secretion in the stomach. The H2-receptor antagonists are effective at suppressing the volume and acidity of parietal cell secretions. Duodenal ulcers usually heal in 6 to 8 weeks, and gastric ulcers may require up to 12 weeks of therapy. All of the H2-receptor antagonists are available OTC for the short-term (2 weeks) treatment of GERD.

Prototype Drug: Ranitidine

Therapeutic Class: Antiulcer drug

Pharmacologic Class: H2-receptor antagonist

ACTIONS AND USES: Ranitidine acts by blocking H2 receptors in the stomach to decrease acid production. It has a higher potency than cimetidine, which allows it to be administered once daily, usually at bedtime. Adequate healing of the ulcer takes approximately 4 to 8 weeks, although those at high risk for PUD may continue on drug maintenance for prolonged periods to prevent recurrence. Gastric ulcers require longer therapy for healing to occur. Intravenous (IV) and intramuscular (IM) forms are available for the treatment of acute, stress-induced bleeding ulcers. Ranitidine is available in a dissolving tablet form for treating GERD in children and infants older than 1 month of age. 

ADMINISTRATION ALERT: Administer after meals and monitor liver and renal function.

Pregnancy category B (Read about drug use in relation to pregnancy)

ADVERSE EFFECTS: Adverse effects are uncommon and mild. Ranitidine does not cross the blood–brain barrier to any appreciable extent, so it does not cause the confusion and

CNS depression observed with cimetidine. Although rare, severe reductions in the number of red and white blood cells and platelets are possible; thus, periodic blood counts may be performed. High doses may result in impotence or loss of libido in men.

Contraindications: Contraindications include hypersensitivity to H2-receptor antagonists, acute porphyria, and OTC administration in children less than 12years of age.

INTERACTIONS: Drug–Drug: Ranitidine has fewer drug–drug interactions than cimetidine. Ranitidine may reduce the absorption of cefpodoxime, ketoconazole, and itraconazole. Antacids should not be given within 1 hour of H2-receptor antagonists because the effectiveness may be decreased due to reduced absorption. Smoking decreases the effectiveness of ranitidine.

Lab Tests: Ranitidine may increase the values of serum creatinine, AST, ALT, LDH, alkaline phosphatase, and bilirubin. It may produce false positives for urine protein.

Herbal/Food: Absorption of vitamin B12 depends on an acidic environment; thus, deficiency may occur. Iron is also better absorbed in an acidic environment.

RELATED;

1. PROTON PUMP INHIBITORS  

2. ANTIBIOTICS  

3. PEPTIC ULCER DISEASE

4.  PHARMACOLOGY AND THERAPEUTICS

REFERENCES

GARLIC FOR CARDIOVASCULAR HEALTH

 

INTRODUCTION: Garlic also scientifically known as Allium sativum, is one of the best-studied herbs. Several substances, known as alliaceous oils, have been isolated from garlic and shown to have pharmacologic activity.

Dosage forms include eating prepared garlic oil or the fresh bulbs from the plant. Modern claims for garlic uses have focused on the cardiovascular system: treatment of high blood lipid levels, atherosclerosis, and hypertension. Other modern claims are that garlic reduces blood glucose levels and has antibacterial and antiviral properties. Like many other supplements, garlic likely has some health benefits, but controlled, scientific studies are often lacking and the results are mixed. Garlic has been shown to decrease the aggregation or “stickiness” of platelets, thus producing an anticoagulant effect. There is some research to show that the herb has a small effect on lowering blood cholesterol. Evidence on the effects of the herb on blood pressure is mixed. An analysis of the research of the effect of garlic on the common cold concluded that there is insufficient clinical evidence to show any benefit. Garlic is safe for consumption in moderate amounts. Patients taking anticoagulant medications should limit their intake of garlic to avoid bleeding complications. Patients with diabetes should monitor their blood glucose levels closely if taking high doses of garlic.

RELATED;

1.  CARDIOVASCULAR CONDITIONS

REFERENCES

PROTON PUMP INHIBITORS

 

INTRODUCTION: Proton pump inhibitors act by blocking the enzyme responsible for secreting hydrochloric acid in the stomach. They are drugs of choice for the short-term therapy of PUD and GERD. Proton pump inhibitors (PPIs) reduce acid secretion in the stomach by binding irreversibly to K⁺/H⁺ATPase, the enzyme that acts as a pump to release acid (also called H⁺, or protons) onto the surface of the GI mucosa. The PPIs reduce acid secretion to a greater extent than the H2-receptor antagonists and have a longer duration of action.  PPIs heal more than 90% of duodenal ulcers within 4 weeks and about 90% of gastric ulcers in 6 to 8 weeks. Several days of PPI therapy may be needed before patients gain relief from ulcer pain. Beneficial effects continue for 3 to 5 days after the drugs have been stopped. These drugs are used only for the short-term control of peptic ulcers and GERD: Peptic ulcer disease

The typical length of therapy is 4 weeks. Omeprazole and lansoprazole are used concurrently with antibiotics to eradicate H. pylori. Esomeprazole and pantoprazole offer the convenience of once-a-day dosing.

OMEPRAZOLE

Therapeutic Class: Antiulcer drug

Pharmacologic Class: Proton pump inhibitor

ACTIONS AND USES: Omeprazole was the first PPI to be approved for PUD: Both prescription and OTC forms are available. Its pharmacodynamics is discussed in the introduction. Although this drug can take 2 hours to reach therapeutic levels, its effects last up to 72 hours. It is used for the short-term, 4- to 8-week therapy of active peptic ulcers and GERD. Most patients are symptom free after 2 weeks of therapy. It is used for longer periods in patients who have chronic hypersecretion of gastric acid, a condition known as Zollinger–Ellison syndrome.

It is the most effective drug for this syndrome. Omeprazole is available only in oral form.

ADMINISTRATION ALERTS: If possible, administer before breakfast on an empty stomach. It may be administered with antacids. Capsules and tablets should not be chewed, divided, or crushed.

Pregnancy category C. [read about drug use inrelation to pregnancy]

ADVERSE EFFECTS: Adverse effects are generally minor and include headache, nausea, diarrhea, rash, and abdominal pain. Although rare, blood disorders may occur, causing unusual fatigue and weakness. Therapy is generally limited to 2 months. Atrophic gastritis and hypomagnesemia have been reported rarely with prolonged treatment with PPIs.

CONTRAINDICATIONS: The only contraindication is hypersensitivity to the drug. OTC use is not approved for patients under 18 years of age.

INTERACTIONS:

Drug–Drug: Concurrent use with diazepam, phenytoin, and central nervous system (CNS) depressants may cause increased blood levels of these drugs. Concurrent use with warfarin may increase the likelihood of bleeding. Alcohol can aggravate the stomach mucosa and decrease the effectiveness of omeprazole.

Lab Tests: Omeprazole may increase values for ALT, AST, and serum alkaline phosphatase.

Herbal/Food: Ginkgo and St. John’s wort may decrease the plasma concentration of omeprazole.

RELATED;

1. PEPTIC ULCER DISEASE

2.  ANTIACIDS

REFERENCES

ISONIAZID (INH)

 

Therapeutic Class: Antituberculosis drug

Pharmacologic Class: Mycolic acid inhibitor

Actions and uses: Isoniazid is a first-line drug for the treatment of M. tuberculosis because decades of experience have shown it to have a superior safety profile and to be the most effective, single drug for the infection. The drug acts by inhibiting the synthesis of mycolic acids, which are essential components of mycobacterial cell walls. It is bacteriocidal for actively growing organisms but bacteriostatic for dormant mycobacteria. It is selective for M. tuberculosis. Isoniazid may be used alone for chemoprophylaxis, or in combination with other antituberculosis drugs for treating active disease. Approximately 10% of patients will develop resistance to isoniazid during long-term therapy.

Administration alerts: Give on an empty stomach, 1 hour after or 2 hours before meals. For IM administration, administer deep IM, and rotate sites. The drug is pregnancy category C.

Adverse effects: The most common adverse effects of isoniazid are numbness of the hands and feet, rash, and fever. Neurotoxicity is a concern during therapy, and patients may exhibit paresthesia of the feet and hands, convulsions, optic neuritis, dizziness, coma, memory loss, and various psychoses.

Warning: Although rare, hepatotoxicity is a serious and sometimes fatal adverse effect; thus, the patient should be monitored carefully for jaundice, fatigue, elevated hepatic enzymes, or loss of appetite. Liver enzyme tests are usually performed monthly during therapy to identify early hepatotoxicity. Hepatotoxicity usually appears in the first 1 to 3 months of therapy but may occur at any time during treatment. Older adults and those with daily alcohol consumption are at greater risk of developing hepatotoxicity.

Contraindications: Isoniazid is contraindicated in patients with hypersensitivity to the drug and in patients with severe hepatic impairment.

Interactions: Drug–Drug: Aluminum-containing antacids should not be administered concurrently because they can decrease the absorption of isoniazid. When disulfiram is taken with INH, lack of coordination or psychotic reactions may result. Drinking alcohol with INH increases the risk of hepatotoxicity. Isoniazid may increase serum levels of phenytoin and carbamazepine.

Treatment of Overdose: Isoniazid overdose may be fatal. Treatment is mostly symptomatic. Pyridoxine (vitamin B6) may be infused in a dose equal to that of the isoniazid overdose to prevent seizures and to correct metabolic acidosis. The dose may be repeated several times until the patient regains consciousness

RELATED;

1. DRUG USE IN RELATION TO PREGNANCY  

2. TUBERCULOSIS

3.  ETHAMBUTOR

4.  PHARMACOLOGY AND THERAPEUTICS

REFERENCES

SEA VEGETABLES

Sea vegetables, or seaweeds, are a form of marine algae that grow in the upper levels of the ocean, where sunlight can penetrate. Examples of these edible seaweeds include spirulina, kelp, chlorella, arame, and nori, many of which are used in Asian cooking. Sea vegetables are found in coastal locations throughout the world. Kelp, or Laminaria, is found in the cold waters of the North Atlantic and Pacific Oceans. Sea vegetables contain a multitude of vitamins as well as protein. Their most notable nutritional aspect, however, is their mineral content. Plants from the sea contain more minerals than most other food sources, including calcium, magnesium, phosphorous, iron, potassium, and all essential trace elements. Because they are so rich in minerals, seaweeds act as alkalizers for the blood, helping to rid the body of acid conditions (acidosis). Spirulina, kelp, and chlorella are available in capsule or tablet form, or as part of a “greens” mix containing other nutritional ingredients.

RELATED;

1.  GINGER  

2.  GARLIC  

3.  FOOD-DRUG INTERACTIONS

4.  TRADITIONAL AND COMPLIMENTARY MEDICATIONS

REFERENCES

LIDOCAINE

 

ACTIONS AND USES:  Lidocaine, the most frequently used injectable local anesthetic, acts by blocking neuronal pain impulses. It may be injected as a nerve block for spinal and epidural anesthesia. It acts by blocking sodium channels located within the membranes of neurons. Sodium channels

ROUTES OF ADMINISTRATION:  Lidocaine may be given IV, IM, or subcutaneously to treat dysrhythmias.  A topical form is also available.

ADMINISTRATION ALERTS: 1)  Solutions of lidocaine containing preservatives or epinephrine are intended for local anesthesia only and must never be given parenterally for dysrhythmias.  

2)  Do not apply topical lidocaine to large skin areas or to broken or abraded areas, because significant absorption may occur.

3) Do not allow it to come into contact with the eyes.

4) For spinal or epidural block, use only preparations specifically labeled for IV use.

ADVERSE EFFECTS:  When lidocaine is used for anesthesia, side effects are uncommon. An early symptom of toxicity is CNS excitement, leading to irritability and confusion. Serious adverse effects include convulsions, respiratory depression, and cardiac arrest. Until the effect of the anesthetic diminishes, patients may injure themselves by biting or chewing areas of the mouth that have no sensation following a dental procedure.

CONTRAINDICATIONS:  Lidocaine should be avoided in cases of sensitivity to amide-type local anesthetics. Application or injection of lidocaine anesthetic is also contraindicated in the presence of severe trauma or sepsis, blood dyscrasias, dysrhythmias, sinus bradycardia, and severe degrees of heart block.

INTERACTIONS:  Drug–Drug: Barbiturates may decrease the activity of lidocaine. Increased effects of lidocaine occur if taken concurrently with cimetidine, quinidine, and beta blockers. If lidocaine is used on a regular basis, its effectiveness may diminish when used with other medications.

RELATED;

1.  OPIOID ANALGESICS

2.  BARBITURATES

3.  BENZODIAZEPINES

4.  PHARMACOLOGY AND THERAPEUTICS

REFERENCES

CORTICOSTEROIDS (GLUCOCORTICOIDS)

 

OBJECTIVES OF THE DISCUSSION:  By the end of this discussion the learner/medical student will be able to;

1.  Describe the role of corticosteroids in management of pain

2.  Explain the effect of corticosteroids on the human body

3.  List the possible side and adverse effect encountered with use of corticosteroids

INTRODUCTION:  Corticosteroids have numerous therapeutic applications. One of their most useful properties is the ability to suppress severe inflammation. Because of potentially serious adverse effects, however, systemic corticosteroids are reserved for the short-term treatment of severe disease. Corticosteroids are often referred to as glucocorticoids.

TREATING ACUTE OR SEVERE INFLAMMATION WITH CORTICOSTEROIDS:  Corticosteroids are natural hormones released by the adrenal cortex that have powerful effects on nearly every cell in the body. When corticosteroids are used as drugs to treat inflammatory disorders, the doses are many times higher than the amount naturally present in the blood. The uses of corticosteroids include the treatment of neoplasia, asthma, arthritis, and corticosteroid deficiency.  Asthma 

PHARMACODYNAMICS:  Like the NSAIDs, corticosteroids inhibit the biosynthesis of prostaglandins. Corticosteroids, however, affect inflammation by multiple mechanisms. They have the ability to suppress histamine release and can inhibit certain functions of phagocytes and lymphocytes. These multiple actions markedly reduce inflammation, making corticosteroids the most effective medications available for the treatment of severe inflammatory disorders.  Inflammation 

ADVERSE EFFECTS:  When given by the oral or parenteral routes, corticosteroids have a number of serious adverse effects that limit their therapeutic utility. These include suppression of the normal functions of the adrenal gland a condition known as adrenal insufficiency, hyperglycemia, mood changes, cataracts, peptic ulcers, electrolyte imbalances, and osteoporosis.  Peptic ulcers

Because of their effectiveness at reducing the signs and symptoms of inflammation, corticosteroids can mask infections that may be present in a patient. This combination of masking signs of active infection and suppressing the immune response creates a potential for infections to grow rapidly and remain undetected. In that regard therefore, active infection is usually a contraindication for corticosteroids therapy. 

Because the appearance of these adverse effects is a function of the dose and duration of therapy, treatment is often limited to the short-term control of acute disease. When longer therapy is indicated, doses are kept as low as possible and alternate-day therapy is sometimes implemented; the medication is taken every other day to encourage the patient’s adrenal glands to function on the days when no drug is given.

RELATED;

1.  OPIOID ANALGESICS

2.  OPIOID ANALGESICS

3.  MORPHINE

4.  INFLAMMATORY CONDITIONS OF THE HUMAN BODY

REFERENCES

CATEGORIES OF DRUGS IN RELATION TO PREGNANCY

 

INTRODUCTION:  Drug use during pregnancy is one of the most important threats to worry about in order to ensure the safety of the mother and the baby.  In the first place although the mother may have less or no effect, our fear rotates around the growing fetus that may take in the drug via the placenta and develop fetal malformations.

1.  RISK CATEGORY A

INTERPRETATION: Adequate, well-controlled studies in pregnant women have not shown an increased risk of fetal abnormalities to the fetus in any trimester of pregnancy.

EXAMPLE OF DRUGS: Prenatal multivitamins, insulin, thyroxine, folic acid.

2.  RISK CATEGORY B

INTERPRETATION: Animal studies have revealed no evidence of harm to the fetus; however, there are no adequate and well-controlled studies in pregnant women.

OR

Animal studies have shown an adverse effect, but adequate and well-controlled studies in pregnant women have failed to demonstrate risk to the fetus in any trimester.

EXAMPLE OF DRUGS: Penicillins, cephalosporins, azithromycin, acetaminophen, ibuprofen in the first and second trimesters.

3.  RISK CATEGORY C

INTERPRETATION: Animal studies have shown an adverse effect and there are no adequate and well controlled studies in pregnant women.

OR

No animal studies have been conducted and there are no adequate and well controlled studies in pregnant women.

EXAMPLE OF DRUGS: Most prescription medicines; antimicrobials such as clarithromycin, fluoroquinolones, and Bactrim; selective serotonin reuptake inhibitors (SSRIs); corticosteroids; and most antihypertensives.

4.  RISK CATEGORY D

INTERPRETATION: Adequate well-controlled or observational studies in pregnant women have demonstrated a risk to the fetus. However, the benefits of therapy may outweigh the potential risk. For example, the drug may be acceptable if needed in a life-threatening situation or serious disease for which safer drugs cannot be used or are ineffective.

EXAMPLE OF DRUGS: Alcohol, ACE inhibitors, angiotensin receptor blockers (ARBs) in the second and third trimesters, gentamicin, carbamazepine, cyclophosphamide, lithium carbonate, methimazole, mitomycin, nicotine, nonsteroidal antiinflammatory drugs (NSAIDs) in the third trimester, phenytoin, propylthiouracil, streptomycin, tetracyclines, valproic acid.

5.  RISK CATEGORY X

INTERPRETATION: Adequate well-controlled or observational studies in animals or pregnant women have demonstrated positive evidence of fetal abnormalities or risks. The use of the product is contraindicated in women who are or may become pregnant. There is no indication for use in pregnancy.

EXAMPLE OF DRUGS: Clomiphene, fluorouracil, isotretinoin, leuprolide, menotropins, methotrexate, misoprostol, nafarelin, oral contraceptives, raloxifene, ribavirin, statins, temazepam, testosterone and thalidomide, and warfarin.

RELATED;

1.  HEMORRHAGIC DISEASE OF THE NEW BORN  

2.  ENDOMETRIOSIS

3.  OBSTETRICS AND GYNECOLOGY

REFERENCES