Diltiazem


Concise Prescribing Info
Indications/Uses
Listed in Dosage.
Dosage/Direction for Use
Adult : PO Angina pectoris Conventional tab: 30 mg 4 times daily, may increase dose gradually in divided doses at 1-2 day intervals until desired response is achieved. Max: 360 mg daily in divided doses. Modified-release tab/cap: Initial: 60 mg tid, may increase to 360 mg daily in divided doses or 480 mg daily, as necessary. Hypertension Modified-release cap: Initial: 90-120 mg bid, may increase to 180 mg bid if necessary. Max: 360 mg daily. IV Cardiac arrhythmias Initial: 250 mcg/kg via bolus injection over 2 minutes. May give a further dose of 350 mcg/kg after 15 minutes if needed.
Dosage Details
Intravenous
Cardiac arrhythmias
Adult: Initially, 250 mcg/kg via bolus injection over 2 minutes. May give a further dose of 350 mcg/kg after 15 minutes if needed. In patients with atrial fibrillation or flutter: Following bolus injection, initiate infusion at rate of 5-10 mg/hour, may increase in increments of 5 mg/hour up to Max of 15 mg/hour. May continue infusion for up to 24 hours.

Oral
Angina pectoris
Adult: Conventional tab: 30 mg 4 times daily, may increase dose gradually in divided doses at 1-2 day intervals until desired response is achieved. Max: 360 mg daily in divided doses. Modified-release tab/cap: Initially, 60 mg tid, may increase to 360 mg daily in divided doses or 480 mg daily, as necessary. Dosage adjustment and dose frequency may vary depending on the formulation.
Elderly: Modified-release tab/cap: Initially, 60 mg bid, may increase carefully to 240 mg once daily if heart rate remains >50 beats/min.

Oral
Hypertension
Adult: Modified-release cap: Initially, 90-120 mg bid, may increase to 180 mg bid if necessary. Max: 360 mg daily.
Elderly: Modified-release cap: Initially, 60 mg bid, may increase carefully to 240 mg once daily.
Renal Impairment
Angina pectoris: Modified-release tab/cap: Initially, 60 mg bid, may increase carefully to 240 mg once daily if heart rate remains >50 beats/min.

Hypertension: Modified-release cap: Initially, 60 mg bid, may increase carefully to 240 mg once daily.
Hepatic Impairment
Angina pectoris: Modified-release tab/cap: Initially, 60 mg bid, may increase carefully to 240 mg once daily if heart rate remains >50 beats/min.

Hypertension: Modified-release cap: Initially, 60 mg bid, may increase carefully to 240 mg once daily.
Administration
Normal Release Prep: May be taken with or without food.
Reconstitution
IV infusion: Further dilute solution with 0.9% NaCl, dextrose 5% in water, dextrose 5% in water with 0.45% NaCl to make a Max final concentration of 1 mg/mL.
Contraindications
Sick sinus syndrome, 2nd or 3rd degree atrioventricular (AV) block without a functioning pacemaker, severe bradycardia (<50 beats/minute), hypotension (<90 mmHg systolic), severe CHF, acute myocardial infarction and pulmonary congestion; IV: atrial fibrillation or flutter with accessory bypass tract (e.g. Wolff-Parkinson-White syndrome), ventricular tachycardia. Lactation. Concomitant use with ivabradine, dantrolene and IV β-blockers.
Special Precautions
Patient with reduced left ventricular dysfunction, intestinal obstruction, 1st degree AV block; diabetes mellitus, pre-existing bronchial hyperactivity, supraventricular arrhythmias with comprised haemodynamics (IV). Renal and hepatic impairment. Elderly. Pregnancy.
Adverse Reactions
Significant: AV block or sinus bradycardia, hypotension with or without syncope, mood changes, bronchospasm (including asthma aggravation). Rarely, elevated hepatic transaminases (e.g. alkaline phosphatase, LDH, AST, ALT), hepatic injury.
Cardiac disorders: Palpitations, ventricular extrasystoles (IV).
Gastrointestinal disorders: Constipation, dyspepsia, gastric pain, nausea.
General disorders and admin site conditions: Malaise, asthenia; inj site reaction (e.g. itching, burning).
Metabolism and nutrition disorders: Oedema, peripheral oedema.
Nervous system disorders: Headache, dizziness.
Skin and subcutaneous tissue disorders: Erythema multiforme including Stevens-Johnson syndrome, toxic epidermal necrolysis; exfoliative dermatitis.
Vascular disorders: Flushing.
IV/Parenteral/PO: C
Patient Counseling Information
This drug may cause dizziness and malaise, if affected, do not drive or operate machinery. Avoid abrupt withdrawal.
MonitoringParameters
Monitor heart rate, blood pressure, ECG, kidney and liver function, signs and symptoms of respiratory impairment.
Overdosage
Symptoms: Hypotension leading to collapse and acute kidney injury, sinus bradycardia with or without isorhythmic dissociation, sinus arrest, atrioventricular (AV) conduction disturbances, cardiac arrest. Management: Supportive and symptomatic treatment. Manage conduction disturbances and heart block with cardiac pacing. Perform gastric lavage and administer activated charcoal and/or IV calcium for ventilatory support. Consider corrective treatments such as atropine, vasopressors (e.g. dopamine, norepinephrine), and inotropic agents (e.g. isoproterenol, dopamine, dobutamine) for bradycardia, hypotension, and cardiac failure, respectively.
Drug Interactions
Increased depression of cardiac conduction, risk of bradycardia and AV block with amiodarone, digoxin, and clonidine. Potentiated depressive effects on cardiac contractility, conductivity, and automaticity, and vascular dilatation of anaesthetics. Increased antihypertensive effect with α-antagonists. Increased serum concentration of ciclosporin, phenytoin, carbamazepine, cilostazol, benzodiazepine (e.g. midazolam, triazolam), buspirone, quinidine, corticosteroids (e.g. methylprednisolone), lithium and theophylline. Increased plasma concentration with CYP3A4 inhibitors (e.g. cimetidine). Decreased serum concentration with CYP3A4 inducers (e.g. rifampicin). Increased cardiovascular effect (e.g. hypotension) of IV ionic X-ray contrast media. May enhance effects of antiplatelet drugs. Increased risk of myopathy and rhabdomyolysis with concomitant use of statins metabolised by CYP3A4 (e.g. atorvastatin, fluvastatin, simvastatin).
Potentially Fatal: Increased risk of lethal ventricular fibrillation with dantrolene infusion. Enhanced hypotensive effect, increased risk of bradycardia and signs of heart failure with β-blockers. Increased bradycardic effect of ivabradine.
Food Interaction
Increased serum concentration with grapefruit or grapefruit juice. Decreased serum concentration with St John’s wort.
Action
Description: Diltiazem, a benzothiazepine calcium channel blocker, inhibits the influx of Ca ions during depolarisation of the vascular smooth muscles and myocardium thereby producing relaxation of coronary vascular muscles and coronary vasodilation and increases myocardial oxygen delivery.
Onset: Oral: 30-60 minutes (immediate release); IV: 3 minutes (bolus).
Duration: IV: 1-3 hours (bolus); 0.5-10 hours (continuous infusion, after discontinuation).
Pharmacokinetics:
Absorption: Almost completely absorbed from the gastrointestinal tract after oral administration. Bioavailability: Approx 40% (oral). Time to peak plasma concentration: 2-4 hours (immediate-release); 11-18 hours (extended-release tab); 10-14 hours (extended-release cap).
Distribution: Present in breastmilk. Volume of distribution: 3-13 L/kg. Plasma protein binding: 70-80%.
Metabolism: Undergoes extensive first-pass metabolism by CYP450 and conjugation to N-monodesmethyldiltiazem, desacetyldiltiazem, desacetyl-N-monodesmethyldiltiazem, desacetyl-O-desmethyldiltiazem and desacetyl-N,O-desmethydiltiazem.
Excretion: Via urine (2-4% as unchanged drug), faeces. Elimination half-life: Oral: 3-4.5 hours (immediate-release); 6-9 hours (extended-release tab); 4-9.5 hours (extended-release cap). IV: Approx 3-4 hours; 4-5 hours (continuous infusion).
Chemical Structure

Click on icon to see table/diagram/image
Storage
Cap/tab: Store at 25°C. Protect from light. Avoid excessive heat and humidity. Solution for injection: Store between 2-8°C. Do not freeze.
MIMS Class
ATC Classification
C08DB01 - diltiazem ; Belongs to the class of benzothiazepine derivative selective calcium-channel blockers with direct cardiac effects. Used in the treatment of cardiovascular diseases.
Disclaimer: This information is independently developed by MIMS based on Diltiazem from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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