4.6. Pregnancy and Lactation
Although animal studies have not shown any teratogenic effects, verapamil should not be given during the first trimester of pregnancy unless, in the clinician's judgement, it is essential for the welfare of the patient.
Verapamil is excreted into the breast milk in small amounts and is unlikely to be harmful. However, rare hypersensitivity reactions have been reported with verapamil and therefore it should only be used during lactation if, in the clinician's judgement, it is essential for the welfare of the patient.
4.7. Effects on Ability to Drive and Use Machines
Depending on individual susceptibility, the patient’s ability to drive a vehicle, operate machinery or work under hazardous conditions may be impaired. This is particularly true in the initial stages of treatment, when changing over from another drug or when the dose is raised. Like many other common medicines, verapamil has been shown to increase the blood levels of alcohol and slow its elimination. Therefore, the effects of alcohol may be exaggerated.
4.8. Undesirable Effects
Reactions from Postmarketing Surveillance or Phase IV Clinical Trials
The following adverse events reported with verapamil are listed below by system organ class:
Immune system disorders: allergic reactions (e.g. erythema, pruritus, urticaria) are very rarely seen.
Nervous system disorders: headache, dizziness, paresthesia, tremor and extrapyramidal syndrome.
Ear and labyrinth disorders: vertigo and tinnitus.
Cardiac disorders/vascular disorders: bradycardic arrhythmias such as sinus bradycardia, sinus arrest with asystole, 2nd and 3rd degree AV block, bradyarrhythmia in atrial fibrillation, peripheral oedema, palpitations, tachycardia, development or aggravation of heart failure and hypotension. There have been rare reports of flushing.
Gastrointestinal disorders: nausea, vomiting, constipation, ileus and abdominal pain/discomfort. Gingival hyperplasia may occur very rarely when the drug is administered over prolonged periods, and is fully reversible when the drug is discontinued.
Skin and subcutaneous tissue disorders: ankle oedema, Quincke’s oedema, Steven-Johnson syndrome, erythema multiforme, erythromelalgia, alopecia and purpura.
Musculoskeletal and connective tissue disorders: muscular weakness, myalgia and arthralgia.
Reproductive system and breast disorders: impotence (erectile dysfunction) has been rarely reported and isolated cases of galactorrhoea. On very rare occasions, gynaecomastia has been observed in elderly male patients under long-term verapamil treatment, and is fully reversible in all cases when the drug was discontinued.
General disorders and administration site conditions: fatigue.
Investigations: A reversible impairment of liver function characterized by an increase of transaminase and/or alkaline phosphatase may occur on very rare occasions during verapamil treatment and is most probably a hypersensitivity reaction. Rises in blood prolactin levels have been reported.
4.9. Overdose
The course of symptoms in verapamil intoxication depends on the amount taken, the point in time at which detoxification measures are taken and myocardial contractility (age-related). The main symptoms are as follows: blood pressure fall (at times to values not detectable), shock symptoms, loss of consciousness, 1st and 2nd degree AV block (frequently as Wenckebach's phenomenon with or without escape rhythms), total AV block with total AV dissociation, escape rhythm, asystole, bradycardia up to high degree AV block and, sinus arrest, hyperglycaemia, stupor and metabolic acidosis. Fatalities have occurred as a result of overdose.
The therapeutic measures to be taken depend on the point in time at which verapamil was taken and the type and severity of intoxication symptoms. In intoxications with large amounts of slow-release preparations (Securon SR and Half Securon SR), it should be noted that the release of the active drug and the absorption in the intestine may take more than 48 hours. Verapamil hydrochloride cannot be removed by haemodialysis. Depending on the time of ingestion, it should be taken into account that there may be some lumps of incompletely dissolved tablets along the entire length of the gastrointestinal tract, which function as active drug depots.
General measures to be taken: Gastric lavage with the usual precautions, even later than 12 hours after ingestion, if no gastrointestinal motility (peristaltic sounds) is detectable. Where intoxication by Securon SR or Half Securon SR is suspected, extensive elimination measures are indicated, such as induced vomiting, removal of the contents of the stomach and the small intestine under endoscopy, intestinal lavage, laxative, high enemas. The usual intensive resuscitation measures apply, such as extrathoracic heart massage, respiration, defibrillation and/or pacemaker therapy.
Specific measures to be taken: Elimination of cardiodepressive effects, hypotension or bradycardia. The specific antidote is calcium, e.g. 10 ‑20 ml of a 10% calcium gluconate solution administered intravenously (2.25 - 4.5 mmol), repeated if necessary or given as a continuous drip infusion (e.g. 5 mmol/hour).
The following measures may also be necessary: In case of 2nd or 3rd degree AV block, sinus bradycardia, asystole - atropine, isoprenaline, orciprenaline or pacemaker therapy. In case of hypotension - dopamine, dobutamine, noradrenaline. If there are signs of continuing myocardial failure - dopamine, dobutamine, if necessary repeated calcium injections.
5. Pharmacological Properties
5.1. Pharmacodynamic Properties
Verapamil, a phenylalkylamine calcium antagonist, has a balanced profile of cardiac and peripheral effects. It lowers heart rate, increases myocardial perfusion and reduces coronary spasm. In a clinical study in patients after myocardial infarction, verapamil reduced total mortality, sudden cardiac death and reinfarction rate.
Verapamil reduces total peripheral resistance and lowers high blood pressure by vasodilation, without reflex tachycardia. Because of its use‑dependent action on the voltage-operated calcium channel, the effects of verapamil are more pronounced on high than on normal blood pressure.
As early as day one of treatment, blood pressure falls; the effect is found to persist also in long‑term therapy. Verapamil is suitable for the treatment of all types of hypertension: for monotherapy in mild to moderate hypertension; combined with other antihypertensives (in particular with diuretics and, according to more recent findings, with ACE inhibitors) in more severe types of hypertension. In hypertensive diabetic patients with nephropathy, verapamil in combination with ACE inhibitors led to a marked reduction of albuminuria and to an improvement of creatinine clearance.
5.2. Pharmacokinetic Properties
Absorption: More than 90% of an orally-administered dose of verapamil is absorbed. Due to an intensive hepatic first‑pass metabolism, the absolute bioavailability is about 22% with a variability of about 10 ‑ 35%. Under multiple dosing, bioavailability increases by about 30%. Bioavailability is not affected by food consumption.
Distribution, biotransformation and elimination: Plasma concentrations reach their peak 4 - 8 hours after drug intake. Plasma protein binding of verapamil is about 90%. The elimination half‑life is about 5 ‑ 8 hours. The mean residence time of modified-release verapamil is 13 hours. After repeated single daily doses, steady-state conditions are reached between 3 - 4 days.
Within 5 days, approximately 70% of an orally-administered dose is excreted in the urine and about 16% with the faeces. Only 3 - 4 % is eliminated renally as unchanged drug. The drug is extensively metabolized. A number of metabolites are generated in humans (twelve have been identified). Of these metabolites only norverapamil has any appreciable pharmacological effect (approximately 20% that of the parent compound, which was observed in a study with dogs). Norverapamil represents about 6% of the dose eliminated in urine. Norverapamil can reach steady‑state plasma concentrations approximately equal to those of verapamil itself. Renal insufficiency does not affect the kinetics of verapamil.
At-risk patients: In patients with liver cirrhosis, bioavailability is increased and elimination half‑life is prolonged. In patients with compensated hepatic insufficiency, no influence on the kinetics of verapamil was observed.
5.3. Preclinical Safety Data
None stated.
6. Pharmaceutical Particulars
6.1. List of Excipients
Microcrystalline cellulose, sodium alginate, povidone, magnesium stearate, purified water, hydroxypropyl methylcellulose, polyethylene glycol 400, polyethylene glycol 6000, talc, titanium dioxide (E171), l-green lake [quinoline yellow (E104) and indigo carmine (E132)], montan glycol wax.
6.2. Incompatibilities
None stated.
6.3. Shelf Life
5 years.
6.4. Special Precautions for Storage
Do not store above 25oC and store in the original package – blister pack.
Do not store above 25oC and keep the container tightly closed – bottle pack.
6.5. Nature and Contents of Container
Calendar pack consisting of a PVC/PVDC blister in a cardboard outer container. Pack size: 28 tablets.
Polypropylene bottle with polyethylene stopper. Pack size: 100 tablets.
6.6. Special precautions for disposal of a used medicinal product
There are no specific instructions for use/handling. The tablets should not be chewed, but may be halved without affecting the modified-release form.
7. Marketing Authorisation Holder
Abbott Laboratories Limited
Queenborough
Kent
ME11 5EL
United Kingdom
8. Marketing Authorisation Number
PL 00037/0369
9. Date of First Authorisation/Renewal of Authorisation
14 March 2002
10. Date of (Partial) Revision of the Text
To be updated. 02nd April 2009