Review of Pharmacology - 9E (2015)

Review of Pharmacology
• Angiotensin II binds to AT1 receptors and causes vasoconstriction and release of aldosterone.
• Angiotensin II is one of the most potent vasoconstrictors in body.
• Angiotensin II increases thirst sensation through the subfornical organ (SFO) of the brain.
• It increases secretion of ATCH in the anterior pituitary.
• It also potentiates the release of norepinephrine by direct action on postganglionic sympathetic fibers.
225. Ans. (b) Thrombolytic (Ref: Harrison 17/e p1537; KDT 6/e p607; Braunwald 7/e p1183, 118)
Thrombolytics are indicated only in ST elevation MI (STEMI) whereas these are contra-indicated in non-STEMI.
226. Ans. (d) Beta blockers (Ref: Harrison 17/e p1577, 1578; KDT 6/e p295)
For details see chapter 19
227. Ans. (b) Increased RR Interval in ECG (Ref: Ganong 22/e p554; KDT 6/e p495)
Vagus is a parasympathetic nerve. It depresses the heart and result in decreased heart rate which is seen as increased RR
interval in ECG. It also decreases the force of contraction and cardiac output slightly.
228. Ans. (b) Reduction in filtration fraction (Ref: Goodman & Gilman 11/e p804)
• Angiotensin II shifts the renal pressure natriuresis curve to right and helps to adjust the sodium level of the
body according to dietary intake of sodium (more excretion with more intake and less excretion with less
consumption). ACE inhibitors block this action of angiotensin II and cause leftward shift of renal pressure
natriuresis curve, so that if sodium intake is decreased much more natriuresis can occur.
• ACE inhibitors increase renal blood flow without increasing GFR and thus result in reduction of filtration
fractio
• ACE inhibitors do not significantly increase heart rate.
• There are variable effect on various vascular beds with ACE inhibitors, these can dilate large arteries.
Cardiovascular System
210
229. Ans (c) Inhaled salbutamol (Ref: Harrison, 17/e p284; KDT 6/e p124)
• The characterstic features given in the question are of hyperkalemia. It can be treated by calcium gluconate, insulin
(glucose is added to prevent hypoglycemia) or sodium bicarbonate which can shift K + in the cells. Salbutamol by i.v.
or inhalational route promote cellular uptake of K + and thus can be used for hyperkalemia.
230. Ans. (d) PTCA (Ref: Harrison 17/e p1537; KDT 6/e p538)
• It is a characterstic case of ST elevation MI (STEMI). Treatment of choice for STEMI is percutaneous coronary intervention
(PCI). Thrombolytics like t PA may also be employed.
231. Ans. (b) Verapamil (Ref: KDT 6/e p530)
All CCBs cause smooth muscle relaxation in blood vessels and extravascular (bronchus, GIT, urinary bladder, uterus)
organs.
232. Ans. (d) Causes hyperuricemia (Ref: KDT 6/e p488)
Losartan is a non-competitive AT1 receptor antagonist. It does not increase bradykinin levels and thus is not associated
with cough and angioedema. It produces a long acting metabolite. It does not cause hyperuricemia.
233. Ans. (a) Diabetic nephropathy with albuminuria (Ref: KDT 6/e p484)
ACE inhibitors are first choice drugs for diabetic patients with hypertension. These are however contra-indicated in pregnancy
and other conditions mentioned in the question.
234. Ans. (a) Atenolol (Ref: KDT 6/e p142, 143)
Beta blockers should never be given alone (or before α-blockers) in pheochromocytoma. There is excess of catecholamines
in the circulation in this condition. They increase BP by acting on α-receptors. Beta blockers will result in further increase
in blood pressure by antagonizing b 2
mediated vasodilatation. Thus, the patient may end in hypertensive crisis. To avoid
this complication, α-blockers should be given before β-blockers or combined α and b-blockers should be given.
235. Ans. (a) Juxtaglomerular apparatus (Ref: KK Sharma 2007/250; KDT 6/e p482)
236. Ans. (a) Fenoldopam (Ref: KK Sharma 2007/176, 261, 292; Katzung 11/e p180-181)
• Nitric oxide donors include:
––
Sodium nitroprusside
––
Organic nitrates
––
Nitrites
––
Hydralazine
––
Propofol
––
Nebivolol
• Fenoldopam is a selective D 1
agonist useful in hypertensive emergencies.
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