Antihypertensive Drugs MCQs

Ans. is 'b' i.e., Methyldopa o Centrally acting sympatholytic antihypertensives are clonidine, methyldopa, guanabenz, guanfacine, moxonidine and rilmenidine.

Prazosin produces first- dose hypotension, presumably by blocking alpha-1- receptors. This effect is minimized by initially giving the drug in small, divided doses. Other options do not cause first-dose hypotension. Reference: Basic & Clinical Pharmacology, Fourteenth Edition By Bertram G. Katzung Pg. no. 182

This patient's clinical presentation is consistent with acute pulmonary edema due to severely elevated blood pressure (hypertensive emergency). In such cases, intravenous vasodilators (nitroglycerine, sodium nitroprusside) are often used to improve the acute heart failure by reducing preload and afterload. Nitrates are metabolized within vascular smooth muscle cells to nitric oxide, which activates guanylate cyclase and promotes the conversion of guanosine triphosphate (GTP) to cyclic guanosine monophosphate (cGMP). Increased levels of cGMP lead to decreased intracellular calcium (reduces the activity of myosin light-chain kinase) and activation of myosin light chain phosphatase. This promotes myosin light-chain dephosphorylation and vascular smooth muscle relaxation. Reference: Basic & Clinical Pharmacology, Fourteenth Edition By Bertram G. Katzung Pg. no. 221

Increased sympathetic nervous system activity occurs if clonidine therapy is abruptly stopped after prolonged administration. Uncontrolled elevation in blood pressure can occur. Patients should be slowly weaned from clonidine while other antihypertensive medications are initiated. Other options do not cause increased sympathetic activity after abrupt discontinuation. Reference Basic & Clinical Pharmacology, Fourteenth Edition By Bertram G. Katzung Pg. no. 185

The experimental agent is able to do both vasodilation and to decrease the release of insulin in response to glucose. The question is which known drug has similar effects. The answer is diazoxide, a K+ channel opener with hyperglycemic effects; Diazoxide is a direct acting peripheral vasodilator that decreases both systolic and diastolic blood pressure. Specifically, diazoxide opens K channels on vascular smooth muscle, causing hyperpolarization and vasodilation, resulting in a decrease in peripheral vascular resistance. Opening K channels on pancreatic beta cells causes hyperpolarization and decreased calcium entry through voltage-gated calcium channels. As a result, diazoxide decreases insulin secretion in response to glucose. Reference : Basic & Clinical Pharmacology, Fourteenth Edition By Bertram G. Katzung Pg no. 183-84

This drug causes dilation of resistance vessels (arterioles) but not of capacitance vessels (venules). Minoxidil is administered orally for treatment of severe to malignant hypertension that is refractory to other drugs. Reflex tachycardia and fluid retention may be severe and require the concomitant use of a loop diuretic and a beta-blocker. Minoxidil causes serious sodium and water retention, leading to volume overload, edema, and congestive heart failure. Minoxidil treatment also causes hypertrichosis (the growth of body hair). This drug is used topically to treat male pattern baldness. Option(A) This agent is used to treat male pattern baldness. Option(C) This agent is not associated with muscle wasting. Option(D) This agent does not cause uremic pericarditis. Reference Basic & Clinical Pharmacology, Fourteenth Edition By Bertram G. Katzung Pg. no. 178

Avoidance of drugs that may worsen CHF Most antiarrhythmic agents Calcium channel blockers (except amlodipine) NSAIDs Thiazolidinediones (e.g., pioglitazone) Inhalation anesthetics Cautious selection of antidepressants due to numerous interactions and adverse effects when used with HF drugs (SSRIs may be used judiciously) Reference: Basic & Clinical Pharmacology, Fourteenth Edition By Bertram G. Katzung Pg no. 221, 222

Furosemide is a loop diuretic with important interactions that treating we must be aware of. This agent will potentiate the action of other antihypertensives, and the patient can become hypotensive. GO PANDA ”: G out, O totoxicity, low P otassium, A llergy, N ephritis, D ehydration, A lkalosis. Option(A) Hypokalemia will result when combined with corticosteroids. Option(B) Orthostatic hypotension is worsened by furosemide. Option(C) Ototoxicity results when furosemide is combined with aminoglycoside antibiotics. Reference : Basic & Clinical Pharmacology, Fourteenth Edition By Bertram G. Katzung Pg. no. 177