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MEDICINE MONOGRAPH CODE: [3.28] ID: TIP-MED-000028

Diltiazem Hydrochloride

Active Ingredient / Scientific Identity: Diltiazem Hydrochloride • Class: Non-Dihydropyridine Calcium-Channel Blocker — Benzothiazepine (Schedule H | NLEM 2022)

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THE INDIAN PHARMACIST — Educational Reference Sheet
Profile: Diltiazem Hydrochloride ([3.28] | ID: TIP-MED-000028) • Last Reviewed: 2026-11-10
Source URL: https://theindianpharmacist.com/medicine/3-28-diltiazem-hydrochloride/
Generic / Entity NameDiltiazem Hydrochloride ([3.28])
Verified Indian Brands / RefGeneric Compendial Entry (No Commercial Brand Claimed)
Pharmacological ClassNon-Dihydropyridine Calcium-Channel Blocker — Benzothiazepine (Schedule H | NLEM 2022)
Available Dosage FormsIR Tablets: 30 mg, 60 mg; SR Tablets: 90 mg, 120 mg; CD Once-Daily Capsules: 90 mg, 120 mg, 180 mg, 240 mg; IV
Regulatory ClassificationSchedule H Prescription Drug (To be sold by retail on the prescription of a Registere
Key Warning & Review DateRenal: Caution in CKD; titrate by HR/BP. Hepatic: Extensive hepatic metabolism — reduce dose in cirrhosis
Reviewed: 2026-11-10
Safety Matrix:⚖️ Legal Status: Schedule H Prescription Drug (To be sold by retail o✔️ Standard Clinical Dispensing Precautions

1. Clinical & Scientific Overview

Diltiazem Hydrochloride (TIP-MED-000028, Reference Code [3.28]) is classified under Cardiovascular & Antithrombotic Medicines (Ch 03) as a Non-Dihydropyridine Calcium-Channel Blocker — Benzothiazepine (Schedule H | NLEM 2022). Within the Indian regulatory and compendial framework, it is governed under Schedule H Prescription Drug (To be sold by retail on the prescription of a Registered Medical Practitioner only — Drugs Rules 1945).

Verified Indian Market Examples / Compendial Status:
Representative Indian Market Examples (Edition 2.7 Ch 03 [3.28], p. 34): Dilzem / Dilzem SR / Dilzem CD (Torrent), Angizem CD (Sun), Channel-SR (Micro Labs) — Strengths & Dosage Forms: IR Tablets: 30 mg, 60 mg; SR Tablets: 90 mg, 120 mg; CD Once-Daily Capsules: 90 mg, 120 mg, 180 mg, 240 mg; IV: 5 mg/mL; 2% Anal Gel
Representative Indian Market Examples (Edition 2.7 Ch 03 [3.28], p. 34): Dilzem / Dilzem SR / Dilzem CD (Torrent), Angizem CD (Sun), Channel-SR (Micro Labs) — Strengths & Dosage Forms: IR Tablets: 30 mg, 60 mg; SR Tablets: 90 mg, 120 mg; CD Once-Daily Capsules: 90 mg, 120 mg, 180 mg, 240 mg; IV: 5 mg/mL; 2% Anal Gel
Dosage Forms & Available Strengths:
IR Tablets: 30 mg, 60 mg; SR Tablets: 90 mg, 120 mg; CD Once-Daily Capsules: 90 mg, 120 mg, 180 mg, 240 mg; IV: 5 mg/mL; 2% Anal Gel
Routes: Oral / Parenteral / Topical as specified by formulation

3. Mechanism of Action & Pharmacodynamics

Non-Dihydropyridine Calcium-Channel Blocker — Benzothiazepine (Schedule H | NLEM 2022) acting on target receptor/enzyme pathways in Cardiovascular & Antithrombotic Medicines (Ch 03): clinical efficacy is mediated via Non-Dihydropyridine Calcium-Channel Blocker — Benzothiazepine (Schedule H | NLEM 2022) for Rate control in atrial fibrillation/flutter, PSVT, chronic stable & vasospastic (Prinzmetal) angina, hypertension (2% gel: chronic anal fissure).

4. Therapeutic Indications & Evidence-Supported Uses

  • Rate control in atrial fibrillation/flutter, PSVT, chronic stable & vasospastic (Prinzmetal) angina, hypertension (2% gel: chronic anal fissure)

🇮🇳 Jurisdiction & Indication Note: Indications and schedules reflect Indian compendial and regulatory records (CDSCO / Indian Pharmacopoeia & NFI / NLEM 2022). Where international reference labels (US FDA DailyMed / NCBI StatPearls) are cited for pharmacokinetic or mechanistic parameters, international approvals do not automatically imply CDSCO approval in India.

5. Educational Dosage Context, Formulations & Administration

Educational Dosing & Regimen Summary: IR: 30–60 mg TDS–QID; SR: 90–120 mg BD; CD: 120–240 mg OD (Max 360 mg/day)

Administration & Meal Timing: Take before meals or at bedtime; swallow SR/CD formulations whole without crushing | Morning & Evening (SR) or fixed Morning/Evening slot (CD)

6. Pharmacokinetics, Metabolism & Renal/Hepatic Adjustment

Absorption & Disposition:
Absorption, distribution, metabolism, and excretion follow class pharmacokinetic profile; verify patient renal/hepatic function.
Metabolism & Biotransformation:
Renal: Caution in CKD; titrate by HR/BP. Hepatic: Extensive hepatic metabolism — reduce dose in cirrhosis
Elimination & Renal Adjustment:
Renal: Caution in CKD; titrate by HR/BP. Hepatic: Extensive hepatic metabolism — reduce dose in cirrhosis
Hepatic Impairment Considerations:
Renal: Caution in CKD; titrate by HR/BP. Hepatic: Extensive hepatic metabolism — reduce dose in cirrhosis

7. Contraindications, Precautions & High-Risk Warnings

Contraindications & Red-Flag Precautions:
  • CONTRAINDICATED in sick sinus syndrome, 2nd/3rd-degree AV block (without pacemaker), severe bradycardia (<50 bpm), HFrEF (LVEF <=40%), and WPW with AF

Key Clinical Precautions: Renal: Caution in CKD; titrate by HR/BP. Hepatic: Extensive hepatic metabolism — reduce dose in cirrhosis

8. Adverse Effects Profile

Common & Mechanism-Related Adverse Effects:
  • Bradycardia, dizziness, mild ankle oedema, headache, constipation, fatigue
  • Symptomatic heart block, asystole (especially if combined with Beta-Blockers or Digoxin), worsening heart failure, drug-induced hepatitis
Serious / Dose-Limiting Adverse Effects:
  • Monitor for severe hypersensitivity, organ toxicity, or dose-limiting adverse events.

9. Major Drug–Drug, Drug–Food & Drug–Herb Interactions

  • MODERATE CYP3A4 & P-gp INHIBITOR: Increases levels of Atorvastatin, Simvastatin (max 10 mg!), Apixaban, Rivaroxaban, Digoxin (+20–40%), Carbamazepine, and Cyclosporine; additive AV block with Beta-Blockers/Amiodarone

10. Clinical Monitoring, Patient Counselling & Storage

Clinical & Laboratory Monitoring: Monitor clinical response, baseline renal/hepatic parameters, and relevant serum biomarkers.

Pharmacist Patient Counselling Points:

  • Patient Counselling Checklist: Check pulse regularly; report slow heartbeat (<55 bpm), fainting, or shortness of breath; never combine with a beta-blocker unless directed by a cardiologist
  • Meal & Clock Timing Instruction: Take before meals or at bedtime; swallow SR/CD formulations whole without crushing (Morning & Evening (SR) or fixed Morning/Evening slot (CD))
  • Missed Dose Protocol: Take if remembered within 6h (BD) or 8h (OD); never double dose
  • Geriatric Dispensing Pearl: Preferred over Verapamil when a non-DHP CCB is needed in older adults, but strictly avoid in HFrEF (AGS Beers 2023)

Storage, Stability & Dispensing Safeguards: Store below 25°C–30°C in original moisture- and light-resistant packaging out of reach of children. Available forms: IR Tablets: 30 mg, 60 mg; SR Tablets: 90 mg, 120 mg; CD Once-Daily Capsules: 90 mg, 120 mg, 180 mg, 240 mg; IV: 5 mg/mL; 2% Anal Gel

11. Visual Pharmacology & Mechanism Diagram (svg-v339-01-adme-12-step-journey)

THE 12-STEP ORAL DRUG JOURNEY THROUGH THE HUMAN BODY (LADME) Note: IV bolus enters Step 6 directly (F = 100%); Sublingual & Transdermal routes bypass Step 4–5 Portal First-Pass Metabolism 1. Oral Administration • Tablet / Capsule swallowed • Gastric emptying to duodenum pH 1.5–3.5 (Stomach) 2. Disintegration & Dissolution • Tablet breaks into granules • API dissolves in GI fluid Noyes-Whitney Dissolution Rate 3. GI Epithelial Absorption • Crosses intestinal villi • Passive / Active / P-gp efflux Small Intestine (Large Surface Area) 4. Portal Circulation • Mesenteric veins → Portal vein • Delivers blood to liver sinusoids Pre-systemic Venous Conduit 5. First-Pass Metabolism • Gut & hepatic CYP450 extraction • High: GTN, Propranolol, Morphine Determines Bioavailability (F = f_a × (1-E_H)) 6. Systemic Circulation • Hepatic vein → IVC → Heart • Unbound vs Albumin-bound drug Only FREE drug is active 7–8. Tissue Distribution (Vd) • Capillary permeation to organs • Blood-Brain & Placental barriers Vd = Dose / C_0 (L or L/kg) 9. Target Site of Action • Receptors (GPCR, Ion channel) • Enzymes & Carrier Transporters Pharmacodynamic Effect (E_max, EC50) 10. Hepatic Biotransformation • Phase I (CYP450 Oxidation/Hydrolysis) • Phase II (Glucuronidation/Sulfation) Converts lipophilic drug → hydrophilic metabolite 11. Renal & Biliary Elimination • Nephron: Filtration + Secretion − Reabsorption • Biliary excretion & Enterohepatic recycling Total Clearance CL_tot = CL_renal + CL_hepatic 12. Excretion from the Body • Urine (Primary polar metabolite route) • Bile/Faeces, Expired Air, Sweat, Milk Elimination Half-Life t1/2 = (0.693 × Vd) / CL
svg-v339-01-adme-12-step-journey — 8.1 Complete 12-Step Journey of an Orally Administered Drug (ADME): Figure 8.1: The 12-step physiological journey of a typical orally administered solid dosage form through Liberation, Absorption, Distribution, Metabolism, and Excretion (LADME). Note: Parenteral (IV), sublingual, and inhalational routes bypass gastrointestinal absorption and/or hepatic first-pass metabolism.

12. Authoritative References, Regulatory Sources & Editorial Disclaimer

Primary Compendial & Guideline Reference: Indian Pharmacist Desk Reference — Professional Edition 2.7 (2026–27) • Ch 03 [3.28] (p. 34)

Official Verification Portals: Indian Pharmacopoeia Commission (IPC) & National Formulary of India (NFI) • Central Drugs Standard Control Organization (CDSCO) • Ministry of Health & Family Welfare — NLEM 2022 • NCBI Bookshelf / StatPearls Pharmacology Reference • DailyMed (US FDA Official Prescribing Reference)

Last Medically & Pharmaceutically Reviewed: 2026-11-10 • Verification Status: HANDBOOK_SOURCE_CONTENT

Educational & Clinical Disclaimer: This reference profile is published solely for pharmacy education, academic study, and professional clinical reference. It does not substitute for patient-specific clinical judgement, qualified specialist oncology/medical supervision, or official CDSCO/IP prescribing information. Never self-medicate with prescription, Schedule H/H1/X, NDPS, or oncology medicines.

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Educational Reference Notice: This printout from THE INDIAN PHARMACIST (https://theindianpharmacist.com/medicine/3-28-diltiazem-hydrochloride/, Last Reviewed: 2026-11-10) is an educational reference sheet for students and healthcare learners. It is NOT an official prescribing guideline or patient-specific treatment order.