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| __NOTOC__
| | #REDIRECT [[Verapamil#Warnings]] |
| {{Verapamil}}
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| {{CMG}}; {{AE}} {{AK}}
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| ==WARNINGS==
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| ===Heart failure===
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| Verapamil has a negative [[inotropic ]]effect, which in most patients is compensated by its [[afterload ]]reduction (decreased systemic vascular resistance) properties without a net impairment of ventricular performance. In clinical experience with 4,954 patients, 87 (1.8%) developed [[congestive heart failure]] or [[pulmonary edema]].
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| Verapamil should be avoided in patients with severe [[left ventricular dysfunction]] (eg, [[ejection fraction]] less than 30%) or moderate to severe symptoms of [[cardiac failure]] and in patients with any degree of ventricular dysfunction if they are receiving a [[beta-adrenergic blocker]](see[[Verapamil hydrochloride tablet extended release precautions|PRECAUTIONS]], [[Verapamil hydrochloride tablet extended release drug interactions|Drug interactions]]). Patients with milder ventricular dysfunction should, if possible, be controlled with optimum doses of digitalis and/or diuretics before verapamil treatment. (Note interactions with digoxin under [[Verapamil hydrochloride tablet extended release precautions|PRECAUTIONS]])
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| ===Hypotension===
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| Occasionally, the pharmacologic action of verapamil may produce a decrease in blood pressure below normal levels, which may result in dizziness or symptomatic [[hypotension]]. The incidence of [[hypotension ]]observed in 4,954 patients enrolled in clinical trials was 2.5%. In hypertensive patients, decreases in blood pressure below normal are unusual. Tilt-table testing (60 degrees) was not able to induce[[ orthostatic hypotension]].
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| ===Elevated liver enzymes===
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| Elevations of transaminases with and without concomitant elevations in [[alkaline phosphatase]] and [[bilirubin ]]have been reported. Such elevations have sometimes been transient and may disappear even in the face of continued verapamil treatment. Several cases of hepatocellular injury related to verapamil have been proven by rechallenge; half of these had clinical symptoms ([[malaise]], [[fever]], and/or right upper quadrant pain) in addition to elevation of [[SGOT]], [[SGPT]], and [[alkaline phosphatase]]. Periodic monitoring of liver function in patients receiving verapamil is therefore prudent.
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| ===Accessory bypass tract (Wolff-Parkinson-White or Lown-Ganong-Levine)===
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| Some patients with paroxysmal and/or chronic atrial fibrillation or atrial flutter and a coexisting accessory AV pathway have developed increased antegrade conduction across the accessory pathway bypassing the [[AV node]], producing a very rapid ventricular response or ventricular fibrillation after receiving intravenous verapamil (or [[digitalis]]). Although a risk of this occurring with oral verapamil has not been established, such patients receiving oral verapamil may be at risk and its use in these patients is contraindicated (see[[Verapamil hydrochloride tablet extended release contraindications|CONTRAINDICATIONS]]). Treatment is usually DC-cardioversion. Cardioversion has been used safely and effectively after oral CALAN.
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| ===Atrioventricular block===
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| The effect of verapamil on AV conduction and the [[SA node]] may cause asymptomatic [[first-degree AV block]] and transient [[bradycardia]], sometimes accompanied by nodal escape rhythms. PR-interval prolongation is correlated with verapamil plasma concentrations, especially during the early titration phase of therapy. Higher degrees of [[AV block]], however, were infrequently (0.8%) observed. Marked first-degree block or progressive development to [[second-|second-degree AV block]]or [[third-degree AV block]], requires a reduction in dosage or, in rare instances, discontinuation of verapamil HCl and institution of appropriate therapy, depending upon the clinical situation.
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| ===Patients with hypertrophic cardiomyopathy (IHSS)===
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| In 120 patients with [[hypertrophic cardiomyopathy]] (most of them refractory or intolerant to [[propranolol]]) who received therapy with verapamil at doses up to 720 mg/day, a variety of serious adverse effects were seen. Three patients died in pulmonary edema; all had severe left ventricular outflow obstruction and a past history of[[ left ventricular dysfunction]]. Eight other patients had [[pulmonary edema]] and/or [[severe hypotension]]; abnormally high (greater than 20 mm Hg) [[pulmonary wedge pressure]] and a marked left ventricular outflow obstruction were present in most of these patients. Concomitant administration of [[quinidine ]](see [[Verapamil hydrochloride tablet extended release precautions|PRECAUTIONS]], [[Verapamil hydrochloride tablet extended release drug interactions|Drug interactions]]) preceded the severe hypotension in 3 of the 8 patients (2 of whom developed pulmonary edema). Sinus bradycardia occurred in 11% of the patients, [[second-degree AV block ]]in 4%, and [[sinus arrest]] in 2%. It must be appreciated that this group of patients had a serious disease with a high mortality rate. Most adverse effects responded well to dose reduction, and only rarely did verapamil use have to be discontinued.<ref name="dailymed.nlm.nih.gov">{{Cite web | last = | first = | title = CALAN SR (VERAPAMIL HYDROCHLORIDE) TABLET, FILM COATED, EXTENDED RELEASE [G.D. SEARLE LLC DIVISION OF PFIZER INC] | url = http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=acb6e57b-af44-432f-a4de-a293a2e20121#nlm34090-1 | publisher = | date = | accessdate = }}</ref>
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| ==References==
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| {{Reflist|2}}
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| [[Category:Cardiovascular Drugs]]
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| [[Category:Drugs]]
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