Hypotensive drug choice

The answer is a. (Hardman, p 224.) Epinephrine is the drug of choice to relieve the symptoms of an acute, systemic, immediate hypersensitivity reaction to an allergen (anaphylactic shock). Subcutaneous administration of a 1 1000 solution of epinephrine rapidly relieves itching and urticaria, and this may save the life of the patient when laryngeal edema and bronchospasm threaten suffocation and severe hypotension and cardiac arrhythmias become life-endangering. Norepinephrine, isoproterenol, and atropine are ineffective therapies Angioedema is responsive to antihis-... 

Secondary hypotension is a sign of an underlying disease that should be treated first. If stroke volume is too low, as in heart failure, a cardiac glycoside can be given to increase myocardial contractility and stroke volume. When stroke volume is decreased due to insufficient blood volume, plasma substitutes will be helpful in treating blood loss, whereas aldosterone deficiency requires administration of a mineralocor-ticoid (e.g., fludrocortisone). The latter is the drug of choice for orthostatic hypotension due to autonomic failure. A parasympatholytic (or electrical pacemaker) can restore cardiac rate in bradycardia. 

Clonidine is a selective Oj-adrenergic agonist that exhibits pronounced hypotensive action that is associated with a reduction of overall peripheral vascular resistance, decline in frequency of cardiac contraction, and reduced cardiac output. Clonidine is the drug of choice for treating various degrees of hypertension when used in combination with oral diuretics. 

Procainamide INa (primary) and IKr (secondary) blockade Slows conduction velocity and pacemaker rate prolongs action potential duration and dissociates from INa channel with intermediate kinetics direct depressant effects on sinoatrial (SA) and atrioventricular (AV) nodes Most atrial and ventricular arrhythmias drug of second choice for most sustained ventricular arrhythmias associated with acute myocardial infarction Oral, IV, IM eliminated by hepatic metabolism to /V-acetylprocainamide (NAPA see text) and renal elimination NAPA implicated in torsade de pointes in patients with renal failure Toxicity Hypotension long-term therapy produces reversible lupus-related symptoms... 

Correct choice = A. The choice of tricyclic antid-pressants depends on the tolerance of side effects and the desired duration of action. Orthostatic hypotension (not hypertension) is a side effect of the tricyclic drugs. The tricyclic antidepressants nonspecificaily block the uptake of norepinephrine and serotonin the onset of action requires 2 weeks or longer. These drugs are usually given orally. 

Adenosine is a naturally occurring nucleoside, but at high doses the drug decreases conduction velocity, prolongs the refractory period, and decreases automaticity in the AV node. Intravenous adenosine is the drug of choice for abolishing acute supraventricular tachycardia. It has low toxicity, but causes flushing, chest pain and hypotension. Adenosine has an extremely short duration of action (about 15 seconds). 

Correct answer = B. Nitroglycerin causes throbbing headache in 30 to 60% of patients taking the drug. The other choices are incorrect. [Note Nitroglycerin may cause postural hypotension.]... 

This compound chelates cyanide as cobalticyanide. This drug is known to antagonize cyanide more quickly than the nitrites but its clear superiority has not been established. Intravenous administration of 300 mg of dicobalt edetate in glucose solution is the current treatment of choice in France and the United Kingdom. Serious side effects like vomiting, urticaria, anaphylactoid shock, hypotension, and ventricular arrythmias have been reported in patients receiving Kelocyanor (Van Heijst and Meredith, 1990). 

Patients with fixed cardiac output, e.g. with aorhc stenosis or constrictive pericarditis, are at special risk from reduced cardiac output with drugs that depress the myocardium and vasomotor centre, for they cannot compensate. Induction with propofol or thiopental is particularly liable to cause hypotension in these patients. Hypoxia is obviously harmful. Skilled technique rather than choice of drugs on pharmacological grounds is the important factor. 

Therapeutic doses of morphine have minimal effects on blood pressure, cardiac rate, or cardiac rhythm when patients are supine however, morphine does produce venous and arteriolar vessel dilatation, and orthostatic hypotension may result. Hypovolemic patients are more susceptible to morphine-induced cardiovascular changes (e.g., decreases in blood pressure). Because morphine prompts a decrease in myocardial oxygen demand in ischemic cardiac patients, it is often considered the drug of choice when using opioids to treat pain associated with myocardial infarction. 

Patients who tolerate hypotension poorly should avoid second-generation ai-adrenergic antagonists. This includes patients with poorly controlled angina, serious cardiac arrhythmias, patients with reduced circulating volume, and patients on multiple antihypertensives. These patients are candidates for tamsulosin or finasteride, if drug therapy is deemed necessary. Whether extended-release alfuzosin is also a good choice remains to be elucidated in controlled comparison trials with tamsulosin. 

Norepinephrine may rapidly increase systolic and diastolic pressure in a severely hypotensive patient, which is a desirable effect. However, because of the potent alpha activity of the drug, blood flow to major organs, particularly the kidney, is decreased. In a severely hypotensive patient, this may precipitate renal failure. Thus, norepinephrine would not be a first choice drug in the therapy of such a patient. 

Which of the following drugs is the drug of choice in anaphylaxis associated with bron-chospasm and hypotension ... 

The elderly patient may be especially sensitive to antidepressant drugs that cause sedation, atropine-like side effects, or postural hypotension. Paroxetine (or another SSRI) is the best choice for this patient because it is the least likely of the drugs listed to exert such actions. The answer is (C). 

Antifungal polyene drug of choice for some systemic mycoses binds to er-gosterol to disrupt fungal cell membrane permeability. Tox chills and fever, hypotension, nephrotoxicity (dose-limiting less with liposomal forms). 

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