Question

Which of the following medications can cause a dangerous block of the AV node if dosing is excessive?

Question options:

	a) dalteparin (Fragmin)
	b) nifedipine (Procardia)
	c) hydrochlorothiazide (Microzide)
	d) diltiazem (Cardizem)

Answer 1

Which of the following medications can cause a dangerous block of the AV node if dosing is excessive?

Answer is D. Diltiazem

	a) dalteparin (Fragmin) Dalteparin is a anticoagulant. It prevent formation of clot/ thrombosis. Excessive dose causes bleading .
	b) nifedipine (Procardia) Nifedipin is a dihydropyridine calcium channel blocker. It used to treat angina pectoris and hypertension.It act on the myocardial and vascular smooth mucles by preventing influx of extracellular calcium in to the intracellular space of muscles. This property results coronary artey dialation and peripheral vasular dialatation. It does not suprress SA node or AV node conduction. Excessive dose causes palpitation, tachycardia, hypotension, peripheral edema
	c) hydrochlorothiazide (Microzide) The action of this drug is diuretics. Increase water and sodium excretion throuhg the kidney. Used to treat hypertension. Excessive dose resullts hyperglycemia, hyponatremia,Hypotension , dizziness, headache, tingling sensation on foot and hands .
	d) diltiazem (Cardizem) Diltiazem is a class IV antiarrythmic drug.The main action is to suppress Ca+ mediated depolarization. It suppress automaticity and decrease phase4 depolarization in the SA node resulting bradycardia.It is also used to treat hypertension, angina pectoris.High dose, slow down AV node conduction and bradycaria and hypotension.