Medication Update. (Featured CME Topic: Hypertension).THIAZIDE DIURETICS Mode of Action Inhibition of sodium and chloride reabsorption reabsorption /re·ab·sorp·tion/ (re?ab-sorp´shun) 1. the act or process of absorbing again, as the absorption by the kidneys of substances (glucose, proteins, sodium, etc.) already secreted into the renal tubules. 2. in the distal tubule tubule /tu·bule/ (too´bul) a small tube. collecting tubule one of the terminal channels of the nephrons which open on the summits of the renal pyramids in the renal papillae. of the kidney, resulting in increased urinary excretion of sodium and water. Direct arteriolar arteriolar emanating from or pertaining to arteriole. vasodilation vasodilation /vaso·di·la·tion/ (-di-la´shun) 1. increase in caliber of blood vessels. 2. a state of increased caliber of blood vessels. . Contraindications Known hypersensitivity to thiazides Thiazides A group of drugs used to increase urine output. Mentioned in: Thyroid Function Tests thiazides (thī´ or other sulfonamides Sulfonamides Definition Sulfonamides are medicines that prevent the growth of bacteria in the body. Purpose Sulfonamides are used to treat many kinds of infections caused by bacteria and certain other microorganisms. . Anuria anuria /an·uria/ (an-u´re-ah) complete suppression of urine formation and excretion.anu´ric a·nu·ri·a n. The absence of urine formation. . Adverse Effects Electrolyte abnormalities, including hypokalemia, hypomagnesemia hypomagnesemia /hy·po·mag·ne·se·mia/ (-mag?nes-em´e-ah) abnormally low magnesium content of the blood. hy·po·mag·ne·se·mi·a n. An abnormally low level of magnesium in the blood. , hyponatremia, and hypercalemia may occur. Elevated blood glucose levels have also been reported. Hyperuricemia hyperuricemia /hy·per·uri·ce·mia/ (-u?ri-se´me-ah) uricemia; an excess of uric acid in the blood.hyperurice´mic hy·per·u·ri·ce·mi·a n. An unusually high concentration of uric acid in the blood. is possible, therefore use with caution in patients who suffer from gout. Arrhythmias may be precipitated secondary to electrolyte abnormalities. Hyperlipidemia (increase in total cholesterol, triglycerides, and LDL cholesterol) has occurred. Dermatologic side effects include photosensitivity and an SLE-like syndrome. Drug-Drug Interactions Hypotension may occur when used in combination with ACE inhibitors. Patients taking carbamazepine carbamazepine /car·ba·maz·e·pine/ (kahr?bah-maz´e-pen) an anticonvulsant and analgesic used in the treatment of pain associated with trigeminal neuralgia and in epilepsy manifested by certain types of seizures. may experience symptomatic hyponatremia with thiazide thiazide /thi·a·zide/ (thi´ah-zid) any of a group of diuretics that act by inhibiting the reabsorption of sodium in the proximal renal tubule and stimulating chloride excretion, with resultant increase in excretion of water. use. Corticosteroids may have a synergistic effect on potassium levels, resulting in hypokalemia. Concomitant use of cholestyramine cholestyramine /cho·le·sty·ra·mine/ (ko?le-sti´rah-men) see cholestyramine resin, under resin. cho·le·styr·a·mine n. may result in drug binding. Decreased clearance of lithium may result in an increased risk of lithium toxicity. There is a potential for digitalis toxicity due to a hypokalemia-induced proarrhythmic state. Methotrexate used in combination with thiazides may result in myelosuppression. Concomitant use of NSAIDS may result in decreased diuretic effectiveness and increased potassium levels secondary to decreased synthesis of renal prostaglandins. Propranolol propranolol /pro·pran·o·lol/ (-pran´o-lol) a ß, used as the hydrochloride salt in the treatment and prophylaxis of certain cardiac disorders, the treatment of tremors and of inoperable pheochromocytoma, and the prophylaxis of migraine. may exacerbate hyperglycemia and hypertriglyceridemia. Drug-Food Interactions Food may result in a small (15%) decrease in hydrochlorothiazide efficacy. Available Agents hydrochlorothiazide (HCTZ): Esidrix, Hydrodiuril, Oretic. chlorothiazide chlorothiazide /chlo·ro·thi·a·zide/ (klor?o-thi´ah-zid) a thiazide diuretic used in the form of the base or the sodium salt to treat hypertension and edema. : Diuril. chlorthalidone: Hygronton, Thalitone. indapamide: Lozol. metolazone: Zaroxolyn. Recommended Dose Depends on the agent chosen. Dosage Forms Available Available in many different dosage strengths. Manufacturer Various. References (1.) DRUGDEX System. Hutchison TA, Shahan DR (ed). MICROMEDEX Inc., Greenwood village, Colo (Edition expires 2001) (2.) Martindale: The Complete Drug Reference. Sweetman S (ed). London, Pharmaceutical Press. Electronic version. POTASSIUM-SPARING DIURETICS Mode of Action Amiloride and triamterene interfere with the sodium-potassium exchange at the distal convoluted tubule of the kidney. Spironolactone spironolactone /spir·o·no·lac·tone/ (spi?rah-no-lak´ton) one of the spirolactones, an aldosterone inhibitor that blocks the aldosterone-dependent exchange of sodium and potassium in the distal tubule, thus increasing excretion of sodium acts as an aldosterone antagonist. Aldosterone promotes sodium and water retention. By blocking the actions of aldosterone, spironolactone prevents increases in fluid volume. Contraindications Hypersensitivity to the particular potassium-sparing diuretic. Renal dysfunction, including anuria, elevated serum creatinine, and elevated BUN. Elevated serum potassium levels or potassium supplementation. Triamterene should not be used in patients with severe hepatic disease. Adverse Effects Hyperkalemia Hyperkalemia Definition The normal concentration of potassium in the serum is in the range of 3.5 to 5.0 mM. Hyperkalemia refers to serum or plasma levels of potassium ions above 5.0 mM. is a common side effect of these medications. GI disturbances, including nausea, vomiting, diarrhea, anorexia can occur. Triamterene and spironolactone have been known to cause impotence and sexual dysfunction. Spironolactone may precipitate gynecomastia gynecomastia Breast enlargement in a male. It usually involves only the nipple and nearby tissue of one breast. More rarely, the whole breast grows to a size normal in a female. True gynecomastia is related to an increase in estrogens. or an SLE-like syndrome. Drug-Drug Interactions May experience synergistic effects on potassium elevation with the use of ACE inhibitors, cyclosporine, tacrolimus, and other potassium-sparing diuretics. Concomitant use of NSAIDS may result in decreased diuretic effectiveness and increased potassium levels secondary to decreased synthesis of renal prostaglandins. Decreased clearance of digoxin, lithium, and metformin may result in elevated serum levels of these drugs. Increased metformin levels may increase the risk of developing lactic acidosis. Use with caution in patients taking dofetilide, as there is an increased risk of cardiotoxicity (QT prolongation, torsades de pointes) secondary to competition for the renal cation transport system. Warfarin may have a decreased anticoagulant effect secondary to diuresis-induced concentration of clotting factors. Drug-Food Interactions Amiloride and triamterene should be taken with food to help decrease GI disturbances. Absorption of spironolactone is enhanced when taken with food. Available Agents amiloride: Midamore. triamterene: Dyrenium. spironolactone: Aldactone. Recommended Dose Depends upon the agent chosen. Dosage Forms Available Available in many different dosage strengths. Manufacturer Various. References (1.) DRUGDEX System. Hutchison TA, Shahan DR (ed). MICROMEDEX Inc., Greenwood Village, Co (Edition expires 2001) (2.) Martindale: The complete Drug Reference. Sweetman S (ed). London, Pharmaceutical Press. Electronic version. BETA BLOCKERS Mode of Action Blockade of Beta-1 receptors, primarily Located in cardiac tissue, results in decreased heart rate, decreased contractility, slowed AV conduction, and suppression of automaticity. Contraindications Hypersensitivity to the particular beta blocker agent, cardiogenic shock or overt cardiac failure, severe sinus bradycardia, second and third degree heart block, bronchial asthma or chronic obstructive pulmonary disease chronic obstructive pulmonary disease n. Abbr. COPD A chronic lung disease, such as asthma or emphysema, in which breathing becomes slowed or forced. . Adverse Effects Cardiac side effects include hypotension and bradycardia. CNS side effects include depression, headache, dizziness, and insomnia. Beta blockers may cause cholesterol abnormalities (increase in triglycerides and LDL, decrease in HDL). These agents may induce bronchospasm and antagonize the effects of bronchodilator medications (albuterol) used for the treatment of asthma. Beta blockers have been reported to cause sexual dysfunction, primarily decreased libido and impotence. Drug-Drug Interactions Concomitant use of beta blockers with alpha-1 antagonists may result in an exaggerated hypotensive response to the first does of the alpha antagonist. This is due to suppression of the beta-mediated compensatory mechanism of increased heart rate in response to alpha blockade. Calcium channel blockers Calcium Channel Blockers Definition Calcium channel blockers are medicines that slow the movement of calcium into the cells of the heart and blood vessels. , digoxin, amiodarone, and quinidine quinidine (kwĭn`ĭdēn'), heart muscle relaxant used to maintain regular heart rhythm patterns. It is an alkaloid chemically similar to quinine and, like quinine, occurs naturally in some species of cinchona trees. may have additive cardiovascular effects when used in combination with beta blockers. The actions of beta-2 agonist medications (eg, albuterol) may be antagonized, thus lessening their effectiveness. Hypotension may occur when beta blockers are used in conjunction with fentanyl anesthesia. Beta blockers interact with numerous agents, and these interactions vary depending upon the agent selected. Drug-Food Interactions Beta blockers should be taken in a consistent manner in relation to food consumption, to help prevent fluctuations in bioavailability. Available Agents acebutolol (*)(+): Sectral. atenolol (*): Tenormin. betaxolol (*): Kerlone. bisoprolol (*): Zebeta. carteolol (+): Cartrol. carvedilol (**): Coreg. labetolol (**): Normodyne. metoprolol metoprolol /met·o·pro·lol/ (met?ah-pro´lol) a cardioselective ß used in the form of the succinate and tartrate salts in the treatment of hypertension, chronic angina pectoris, and myocardial infarction. (*): Lopressor, Toprol-XL. nadolol: Corgard. penbutolol (+): Levatol. pindolol (+): Visken. propranolol: Inderal, Inderal-LA. timolol timolol /ti·mo·lol/ (ti´mo-lol) a nonselective beta-adrenergic blocking agent used as the maleate salt in the treatment of hypertension, the treatment and prophylaxis of recurrent myocardial infarction and the prophylaxis of migraine; : Blocadren. Recommended Dose Depends upon the agent chosen. Dosage Forms Available Available in many different dosage strengths. Manufacturer Various. References (1.) DRUGDEX System. Hutchison TA, Shahan DR (ed). MICROMEDEX Inc., Greenwood Village, Colo (Edition expires 2001) (2.) Martindale: The Complete Drug Reference. Sweetman S (ed). London, Pharmaceutical Press. Electronic version. ANGIOTENSIN CONVERTING ENZYME (ACE) INHIBITORS Mode of Action Inhibit the conversion of angiotensin-I to angiotensin-II. Angiotensin-II is a potent vasoconstrictor vasoconstrictor /vaso·con·stric·tor/ (-kon-strik´ter) 1. causing constriction of blood vessels. 2. a nerve or agent that does this. va·so·con·stric·tor n. and promotes the production of aldosterone. Aldosterone promotes sodium and water retention. By inhibiting the production of angiotensin-II, ACE-inhibitors cause vasodilation and indirectly inhibit fluid volume increases that result from the actions of aldosterone. Contraindications Hypersensitivity to the particular ACE inhibitor agent. Pregnancy. Adverse Effects ACE inhibitors may precipitate a dry, nonproductive cough or angioedema. These effects most often disappear when the drug is discontinued. Cardiovascular effects include hypotension, angina, and palpitations. Dizziness, fatigue, headache, and weakness have been reported. GI disturbances include nausea, vomiting, diarrhea, constipation, and abnormal taste. Neutropenia is a rare side effect. Patients with renal dysfunction or collagen vascular diseases collagen vascular diseases Connective tissue diseases, see there are more likely to experience this side effect than the general population. Hyperkalemia or proteinuria may occur, especially in patients with renal dysfunction. Renal insufficiency is possible, thus renal function should be monitored, especially when starting these agents or increasing the dose. Dermatologic effects include rash and flushing. Impotence has been reported with ACE inhibitor use. Drug-Drug Interactions Concomitant use of NSAIDS may result in decreased ACE inhibitor effectiveness secondary to decreased synthesis of renal prostaglandins. Thiazide and loop diuretics may precipitate postural hypotension (first dose) secondary to vasodilation and a relative depletion of intravascular volume. Potassium-sparing diuretics may have an additive effect on potassium retention, resulting in hyperkalemia. Lithium toxicity has been reported when used in combination with ACE inhibitors. Concomitant use of cyclosporine with ACE inhibitors may cause acute renal failure acute renal failure Acute kidney failure Nephrology An abrupt decline in renal function, triggered by various processes–eg, sepsis, shock, trauma, kidney stones, drug toxicity-aspirin, lithium, substances of abuse, toxins, iodinated radiocontrast. . Drug-Food Interactions Captopril captopril /cap·to·pril/ (kap´to-pril) an angiotensin-converting enzyme inhibitor used in the treatment of hypertension, congestive heart failure, and post–myocardial infarction left ventricular dysfunction. and moexipril experience decreased absorption when taken with food. Available Agents benazepril: Lotensin. captopril: Capoten. enalapril: Vasotec. fosinopril: Monopril. lisinopril: Prinivil. moexipril: Univasc. perindopril: Aceon. quinapril: Accupril. ramipril: Altace. trandolapril: Mavik. Recommended Dose Depends upon the agent chosen. Dosage Forms Available Available in many different dosage strengths. Manufacturer Various. References (1.) DRUGDEX System. Hutchison TA, Shahan DR (ed). MICROMEDEX Inc., Greenwood Village, Colo (Edition expires 2001) (2.) Martindale: The Complete Drug Reference. Sweetman S (ed). London, Pharmaceutical Press. Electronic version, CALCIUM CHANNEL BLOCKERS Mode of Action Inhibition of the influx of calcium through slow channels in the vascular smooth muscles and myocardial tissue during depolarization depolarization /de·po·lar·iza·tion/ (de-po?lahr-i-za´shun) 1. the process or act of neutralizing polarity. 2. in electrophysiology, reversal of the resting potential in excitable cell membranes when stimulated. . This results in systemic and coronary artery vasodilation, decreased myocardial contractility, and sinoatrial sinoatrial /si·no·atri·al/ (si?no-a´tre-al) pertaining to the sinus venosus and the atrium of the heart. si·no·a·tri·al or si·nu·a·tri·al adj. Abbr. (SA) and atrioventricular atrioventricular /atrio·ven·tric·u·lar/ (-ven-trik´u-ler) pertaining to both an atrium and a ventricle of the heart. a·tri·o·ven·tric·u·lar adj. Abbr. (AV) nodal depression. Contraindications Hypersensitivity to the particular calcium channel blocker calcium channel blocker n. Any of a class of drugs that inhibit movement of calcium ions across a cell membrane, used in the treatment of cardiovascular disorders. agent. Second or third degree heart block, Wolfe-Parkinson-White syndrome, or sick sinus syndrome Sick Sinus Syndrome Definition Sick sinus syndrome is a disorder of the sinus node of the heart, which regulates heartbeat. With sick sinus syndrome, the sinus node fails to signal properly, resulting in changes in the heart rate. . Symptomatic hypotension. Congestive heart failure congestive heart failure, inability of the heart to expel sufficient blood to keep pace with the metabolic demands of the body. In the healthy individual the heart can tolerate large increases of workload for a considerable length of time. or coronary artery disease coronary artery disease, condition that results when the coronary arteries are narrowed or occluded, most commonly by atherosclerotic deposits of fibrous and fatty tissue. . Adverse Effects Cardiovascular effects include AV heart block and peripheral edema. Central nervous system effects include headache and dizziness. Gingival gingival (jin´j  v hyperplasia has been reported with some agents. GI disturbances include
constipation.
Drug-Drug Interactions Beta blockers, digoxin, and amiodarone may have additive cardiovascular effects when used in combination with calcium channel blockers. Some agents may inhibit the clearance of digoxin, resulting in increased risk of digoxin toxicity. Cimetidine in combination with nifedipine or diltiazem may result in increased cardiovascular toxicity. Carbemazeine, phenytoin phenytoin /phen·y·to·in/ (fen´i-toin?) an anticonvulsant used in the control of various kinds of epilepsy and of seizures associated with neurosurgery. phen·y·to·in n. , and tacrolimus metabolism may be inhibited by concomitant use with diltiazem. Cyclosporine metabolism may be inhibited by certain calcium channel blockers, resulting in an increased risk of cyclosporine toxicity. Mole antifungal agents may increase the potential for cardiovascular toxicity of dihydropyridine calcium channel blockers due to inhibition of metabolism. Hypotension may occur when calcium channel blockers are used in conjunction with fentanyl anesthesia. Theophylline metabolism is inhibited by diltiazem and alterations in theophylline serum concentrations (increase or decrease) can occur with nifedipine use. Calcuim channel blockers interact with numerous agents, and these interactions vary depending upon the agent selected. Drug-Food Interactions Diltiazem should be taken before meals. Grapefruit juice should be avoided with felpodpine use. Available Agents diltiazem: Cardizem, Cardizem CD, Cardizem SR, Dilacor XR, Tiazac. verapamil verapamil /ve·rap·a·mil/ (ve-rap´ah-mil) a calcium channel blocker that dilates coronary arteries and decreases myocardial oxygen demand, used as the hydrochloride salt in the treatment of angina pectoris and of hypertension and the : Calan. amlodipine: Norvasc. felodipine: Plendil. isradipine: DynaCirc. nicardipine: Cardene, Cardene SR. nifedipine: Adalat, Adalat CC, Procardia, Procardia XL. Recommended Dose Depends upon the agent chosen. Dosage Forms Available Available in many different dosage forms and strengths. Manufacturer Various. References (1.) DRUGDEX System. Hutchison TA, Shahan DR (ed). MICROMEDEX Inc., Greenwood Village, Colo (Edition expires 2001) (2.) Martindale: The Complete Drug Reference. Sweetman S (ed). London, Pharmaceutical Press. Electronic version. ANGIOTENSIN RECEPTOR BLOCKERS (ARB) Mode of Action By blocking the binding of angiotension-II to the angiotensin-II receptor, these agents inhibit the vasoconstriction effects of angiotensin-II and prevent the angiotensin-II-mediated release of aldosterone. Aldosterone promotes sodium and water retention. By inhibiting the production of aldosterone, ARBs indirectly inhibit fluid volume increases that result from the actions of aldosterone. Con traindications Hypersensitivity to the particular ARB agent. Pregnancy Adverse Effects Cardiovascular side effects include orthostatic hypotension and angioedema. Central nervous system side effects include headache, dizziness, and fatigue. GI disturbances, including dyspepsia and diarrhea, have been reported. Muscle cramping, rash, and decreased renal function have also occurred with ARB use. Drug-Drug Interactions Concomitant use of ARBs with lithium may result in increased risk of lithium toxicity secondary to increased renal reabsorption of lithium. Digoxin concentrations should be monitored with candesartan use, as fluctuations in digoxin levels have been reported. Indomethacin may cause decreased effectiveness of losartan. The mechanism of this interaction is unknown. Drug-Food Interactions Food does not appear to interfere with the bioavialability of these agents. Available Agents candesartan: Atacand. irbesartan: Avapro. losartan: Cozaar. telmisartan: Micardis. valsartan: Diovan. Recommended Dose Depends upon the agent chosen. Dosage Forms Available Available in different dosage strengths. Manufacturer Various. References (1.) DRUGDEX System. Hutchison TA, Shahan DR (ed). MICROMEDEX Inc., Greenwood Village, Col (Edition expires 2001) (2.) Martindale: The Complete Drug Reference. Sweetman S (ed). London, Pharmaceutical Press. Electronic version. ALPHA BLOCKERS Mode of Action Selective blockade of alpha-1 receptors results in vasodilation. These agents decrease blood pressure by decreasing total peripheral resistance total peripheral resistance a measure of the total resistance to blood flow provided by the entire vascular system. and venous return. Contraindications Hypersensitivity to the particular alpha blocker agent. Adverse Effects Cardiac effects include orthostatic hypotension, palpitations, bradycardia, and edema. Central nervous system side effects including dizziness, headache, fatigue, and anxiety have been reported. Alpha blockers have been noted to effect cholesterol levels (decrease in total cholesterol, LDL, and triglycerides; increase in HDL). GI effects include nausea, diarrhea, constipation, and vomiting. Genitourinary side effects include nocturia, urinary frequency, impotence, and priapism Priapism Definition Priapism is a rare condition that causes a persistent, and often painful, penile erection. Description Priapism is drug induced, injury related, or caused by disease, not sexual desire. . Drug-Drug Interactions Concomitant use of beta blockers with alpha-1 antagonists may result in an exaggerated hypotensive response to the first dose of the alpha antagonist. This is due to suppression of the beta-mediated compensatory mechanism of increased heart rate in response to alpha blockade. Additive effects on hypotension may occur with concomitant use of verapamil. Cimetidine may exaggerate the hypotensive response of tamulosin secondary to decreased metabolism of tamulosin. Drug-Food Interactions Food does not appear to interfere with the bioavialability of these agents. Available Agents Doxazosin: Cardura. Prazosin prazosin /pra·zo·sin/ (pra´zah-sin) an alpha-adrenergic blocking agent with vasodilator properties, used as the hydrochloride salt in the treatment of hypertension. pra·zo·sin n. : Minipress. Tamulosin: Flomax. Terazosin: Hytrin. Recommended Dose Depends upon the agent chosen. Dosage Forms Available Available in different dosage strengths. Manufacturer Various. References (1.) DRUGDEX System. Hutchison TA, Shahan DR (ed). MICROMEDEX Inc., Greenwood Village, Cob (Edition expires 2001) (2.) Martindale: The Complete Drug Reference. Sweetman S (ed). London, Pharmaceutical Press. Electronic version. (*.) Relative cardioselective activity (beta-1 activity > beta-2 activity). (+.) Intrinsic sympathomimetic sympathomimetic /sym·pa·tho·mi·met·ic/ (-mi-met´ik) 1. mimicking the effects of impulses conveyed by adrenergic postganglionic fibers of the sympathetic nervous system. 2. an agent that produces such an effect. activity (ability to release catecholamines Catecholamines Family of neurotransmitters containing dopamine, norepinephrine and epinephrine, produced and secreted by cells of the adrenal medulla in the brain. to maintain a satisfactory heart rate). (**.) Alpha blocking properties (blocks peripheral alpha receptors to produce peripheral vasodilation). |
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