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Drug Details

Securon SR

• Drug Class Description
  Calcium-channel blockers (class I calcium antagonists).
• Generic Name
  Verapamil - arrhythmias/post MI
• Presentation
  Modified-release tablets. The tablets are oblong, pale green, scored and embossed with two Knoll logos (triangles) on one side.
• Description
  Verapamil Hydrochloride Ph Eur – 240 mg
• Indications
  

  Securon SR is indicated for: The treatment of mild to moderate hypertension. The treatment and prophylaxis of angina pectoris. Secondary prevention of reinfarction after an acute myocardial infarction in patients without heart failure, and not receiving diuretics (apart from low-dose diuretics when used for indications other than heart failure), and where beta-blockers are not appropriate. Treatment is to be started at least one week after an acute myocardial infarction.

• Adult Dosage
  

  Securon SR tablets should not be chewed. Securon SR tablets are scored and may be halved without damaging the modified-release formulation.

  Adults

  Hypertension: One tablet of Securon SR daily. For patients new to verapamil therapy, the physician should consider halving the initial dose to 120 mg (one tablet Half Securon SR). Most patients respond to 240 mg daily (one tablet Securon SR) given as a single dose. If control is not achieved after a period of at least one week, the dosage may be increased to a maximum of two Securon SR tablets daily (one in the morning and one in the evening at an interval of about twelve hours). A further reduction in blood pressure may be achieved by combining Securon SR with other antihypertensive agents, in particular diuretics. Half Securon SR may be used for dose titration purposes.

  Angina pectoris: One tablet of Securon SR twice daily. A small number of patients respond to a lower dose and where indicated, adjustment down to one tablet of Securon SR daily could be made. Half Securon SR may be used for dose titration purposes.

  Secondary prevention of reinfarction after an acute myocardial infarction in patients without heart failure, and not receiving diuretics (apart from low-dose diuretics when used for indications other than heart failure), and where beta-blockers are not appropriate: Treatment is to be started at least one week after an acute myocardial infarction. 360 mg/day in divided doses, to be taken either as one Half Securon SR (120 mg) tablet three times daily, or as one Securon SR (240 mg) tablet in the morning and one Half Securon SR (120 mg) tablet in the evening, on a daily basis

• Child Dosage
  Securon: Under 2 years, 20 mg; over 2 years, 40 - 120 mg. Both two or three times daily. Securon IV: See data sheet.
• Elderly Dosage
  

  The adult dose is recommended unless renal or hepatic function is impaired

• Contra Indications
  

  Hypersensitivity to the active substance or to any of the excipients.

  Cardiogenic shock; acute myocardial infarction complicated by bradycardia, marked hypotension or left ventricular failure; second or third degree atrioventricular (AV) block (except in patients with a functioning artificial pacemaker); sino-atrial block; sick sinus syndrome (except in patients with a functioning artificial pacemaker); uncompensated heart failure; bradycardia of less than 50 beats/minute; hypotension of less than 90 mmHg systolic.

  Patients with atrial flutter/fibrillation in the presence of an accessory pathway (e.g. WPW syndrome) may develop increased conduction across the anomalous pathway and ventricular tachycardia may be precipitated.

• Special Precautions
  1st degree AV block, poor cardiac reserve should be controlled with digitalis and/or diuretics. Bradycardia, conduction disturbances. Hepatic or renal impairment. Pregnancy and lactation.
• Interactions
  

  In vitro metabolic studies indicate that verapamil hydrochloride is metabolized by cytochrome P450 CYP3A4, CYP1A2, CYP2C8, CYP2C9 and CYP2C18. Verapamil has been shown to be an inhibitor of CYP3A4 enzymes and P-glycoprotein (P-gp). Clinically significant interactions have been reported with inhibitors of CYP3A4 causing elevation of plasma levels of verapamil hydrochloride while inducers of CYP3A4 have caused a lowering of plasma levels of verapamil hydrochloride, therefore, patients should be monitored for drug interactions.

  The following are potential drug interactions associated with verapamil:

  Acetylsalicylic acid

  Concomitant use of verapamil with aspirin may increase the risk of bleeding

  Alcohol

  Increase in blood alcohol has been reported.

  Alpha blockers

  Verapamil may increase the plasma concentrations of prazosin and terazosin which may have an additive hypotensive effect.

  Antiarrhythmics

  Verapamil may slightly decrease the plasma clearance of flecainide whereas flecainide has no effect on the verapamil plasma clearance.

  Verapamil may increase the plasma concentrations of quinidine. Pulmonary oedema may occur in patients with hypertrophic cardiomyopathy

  The combination of verapamil and antiarrhythmic agents may lead to additive cardiovascular effects (e.g. AV block, bradycardia, hypotension, heart failure).

  Anticonvulsants

  Verapamil may increase the plasma concentrations of carbamazepine. This may produce side effects such as diplopia, headache, ataxia or dizziness. Verapamil may also increase the plasma concentrations of phenytoin.

  Antidepressants

  Verapamil may increase the plasma concentrations of imipramine.

  Antidiabetics

  Verapamil may increase the plasma concentrations of glibenclamide (glyburide).

  Antihypertensives, diuretics, vasodilators

  Potentiation of the hypotensive effect.

  Anti-infectives

  Rifampicin may reduce the plasma concentrations of verapamil which may produce a reduced blood pressure lowering effect. Erythromycin and telithromycin may increase the plasma concentrations of verapamil.

  Antineoplastics

  Verapamil may increase the plasma concentrations of doxorubicin.

  Barbiturates

  Phenobarbital may reduce the plasma concentrations of verapamil.

  Benzodiazepines and other anxiolytics

  Verapamil may increase the plasma concentrations of buspirone and midazolam.

  Beta blockers

  Verapamil may increase the plasma concentrations of metoprolol and propranolol which may lead to additive cardiovascular effects (e.g. AV block, bradycardia, hypotension, heart failure).

  Intravenous beta-blockers should not be given to patients under treatment with verapamil.

  Cardiac glycosides

  Verapamil may increase the plasma concentrations of digitoxin and digoxin. Verapamil has been shown to increase the serum concentration of digoxin and caution should be exercised with regard to digitalis toxicity. The digitalis level should be determined and the glycoside dose reduced, if required.

  Colchicine

  Colchicine is a substrate for both CYP3A and the efflux transporter, P-glycoprotein (P-gp). Verapamil is known to inhibit CYP3A and P-gp. When verapamil and colchicine are administered together, inhibition of P-gp and/or CYP3A by verapamil may lead to increased exposure to colchicine. Combined use is not recommended.

  H ₂ Receptor antagonists

  Cimetidine may increase the plasma concentrations of verapamil.

  HIV antiviral agents

  Due to the metabolic inhibitory potential of some of the HIV antiviral agents, such as ritonavir, plasma concentrations of verapamil may increase. Caution should be used or dose of verapamil may be decreased.

  Immunosuppressants

  Verapamil may increase the plasma concentrations of ciclosporin, everolimus, sirolimus and tacrolimus.

  Inhaled anaesthetics

  When used concomitantly, inhalation anaesthetics and calcium antagonists, such as verapamil hydrochloride, should each be titrated carefully to avoid additive cardiovascular effects (e.g. AV block, bradycardia, hypotension, heart failure).

  Lipid lowering agents

  Verapamil may increase the plasma concentrations atorvastatin, lovastatin and simvastatin.

  Treatment with HMG CoA reductase inhibitors (e.g., simvastatin, atorvastatin or lovastatin) in a patient taking verapamil should be started at the lowest possible dose and titrated upwards. If verapamil treatment is to be added to patients already taking an HMG CoA reductase inhibitor (e.g., simvastatin, atorvastatin or lovastatin), consider a reduction in the statin dose and retitrate against serum cholesterol concentrations.

  Atorvastatin may increase verapamil levels. Although there is no direct in vivo clinical evidence, there is strong potential for verapamil to significantly affect atorvastatin pharmacokinetics in a similar manner to simvastatin or lovastatin. Consider using caution when atorvastatin and verapamil are concomitantly administered.

  Fluvastatin, pravastatin and rosuvastatin are not metabolized by CYP3A4 and are less likely to interact with verapamil.

  Lithium

  Serum levels of lithium may be reduced. However, there may be increased sensitivity to lithium causing enhanced neurotoxicity.

  Neuromuscular blocking agents employed in anaesthesia

  The effects may be potentiated.

  Serotonin receptor agonists

  Verapamil may increase the plasma concentrations of almotriptan.

  Theophylline

  Verapamil may increase the plasma concentrations of theophylline.

  Uricosurics

  Sulfinpyrazone may reduce the plasma concentrations of verapamil which may produce a reduced blood pressure lowering effect.

  Other

  St. John's Wort may reduce the plasma concentrations of verapamil, whereas grapefruit juice may increase the plasma concentrations of verapamil.

• Adverse Drug Reactions
  

  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, 2^nd and 3^rd 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.