ANPEC

What it is

ANPEC is a verapamil hydrochloride tablet formulation available in 40 mg and 80 mg strengths. Verapamil is a calcium ion influx inhibitor (slow channel blocker or calcium ion antagonist) which exerts its pharmacologic effects by modulating the influx of ionic calcium across the cell membrane of the arterial smooth muscle as well as in conductile and contractile myocardial cells.

Approved indications —

Hypertension — Angina of effort — Angina at rest — Vasospastic angina (including Prinzmetal's variant angina) — Tachyarrhythmias including paroxysmal supra-ventricular tachycardia — Atrial fibrillation with rapid ventricular response — Atrial flutter with rapid ventricular response

Dosing overview

The usual starting dose is one 80 mg tablet two or three times a day. The maintenance dose may be adjusted to 160 mg two or three times a day. Usual maintenance dose is 160 mg twice daily. The individual dose and frequency of dosing should be determined in accordance with the indication and individual patient response. Paediatric dose range is 40 to 360 mg per day in two or three divided daily doses according to age and response.

Key safety warnings

Verapamil has a negative inotropic effect which, in most patients, is compensated by its afterload reduction properties without a net impairment of ventricular performance. However, verapamil should be avoided in patients with severe left ventricular dysfunction (for example, ejection fraction less than 30%, pulmonary wedge pressure above 20 mmHg, or severe symptoms of cardiac failure) and in patients with any degree of ventricular dysfunction if they are receiving a beta-adrenergic blocker. Use with caution in patients with acute myocardial infarction complicated by bradycardia, marked hypotension, or left ventricular dysfunction. 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%. 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 elevations of liver enzymes. Periodic monitoring of liver function in patients receiving verapamil is therefore prudent. Verapamil affects the AV and SA nodes and prolongs AV conduction time. Use with caution as development of second- or third-degree AV block or unifascicular, bifascicular or trifascicular bundle branch block requires discontinuation of subsequent doses of verapamil and institution of appropriate therapy, if needed.

Contraindications

ANPEC is contraindicated in severe left ventricular dysfunction; hypotension (less than 90 mmHg systolic pressure) or cardiogenic shock; sick sinus syndrome (except in patients with a functioning artificial pacemaker); second- or third-degree AV block (except in patients with a functioning artificial pacemaker); patients with atrial flutter or atrial fibrillation and an accessory bypass tract (such as Wolff-Parkinson-White or Lown-Ganong-Levine syndromes), as these patients are at risk to develop ventricular tachyarrhythmia including ventricular fibrillation if verapamil is administered; heart failure with reduced ejection fraction of less than 35% and/or pulmonary wedge pressure above 20 mmHg; patients concomitantly administered ivabradine; simultaneous initiation of treatment with dabigatran etexilate and oral verapamil; treatment initiation with oral verapamil in patients following major orthopaedic surgery who are already treated with dabigatran etexilate; and patients with known hypersensitivity to verapamil hydrochloride or any of the inactive ingredients.

Regulatory history

ANPEC verapamil hydrochloride 40 mg and 80 mg tablet formulations were first listed on the Australian Register of Therapeutic Goods on 7 November 2019.