diltiazem (Cardizem, Dilacor, Tiazac, Cartia, Angiotrofin, Dilcontin)
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Introduction
Tradename: Cardizem, Dilacor*.
Indications
- hypertension
- may be acceptable anti-hypertensive agent in non Q-wave MI
- left ventricular diastolic dysfunction
- angina pectoris
- Raynaud's syndrome
- supraventricular arrhythmias (SVT)
Contraindications
Dosage
Rapid atrial fibrillation:
- Bolus 0.25 mg/kg or 20 mg IV over 2 min.
- Rebolus 15 min later (if necessary) 0.35 mg/kg or 25 mg.
- Infusion: 5-15 mg/hr.
* 180 mg of calcium IV through peripheral line prior to IV diltiazem for rapid atrial fibrillation reduces risk of hypotension[10]
Hypertension: start 30 mg PO QID, max 360 mg/day.
Tabs: 30, 60, 90, 120 mg.
Cardizem CD & Dilacor XR (sustained release)
Tabs: 120, 180, 240, 300 mg.
Cardizem SR (twice daily sustained release)
Tabs: 60, 90, 120 mg.
Cardizem LA: QD dosing; QAM or QHS[7][8]
Tabs: 120, 180, 240, 300, 360, 420 mg
Pharmacokinetics
- metabolized by cyt P450 3A4 (CYP3A4) in the liver
elimination via liver
Monitor
Adverse effects
- common (> 10%)
- less common (1-10%)
- dizziness, bradycardia, 1st degree AV block, edema, EKG abnormalities, asthenia
- uncommon (< 1%)
- 2nd degree AV block, angina, dream disturbances, amnesia, depression, gait abnormalities, insomnia, nervousness, paresthesia, tremor, anorexia, constipation, diarrhea, dysgeusia, dyspepsia, urticaria, photosensitivity, amblyopia, alopecia, hemolytic anemia, leukopenia, purpura, retinopathy, thrombocytopenia, pharyngitis, cough, flu-like syndrome, gingival hyperplasia
- hypotension when used to treat atrial fibrillation with rapid ventricular response[10]
- pretreatment with IV calcium reduces risk (see Dosage above)
- see calcium channel blocker
- overdose:
- drug adverse effects of calcium channel blockers
- drug adverse effects of renin-angiotensin-aldosterone system inhibitors (RAAS inhibitors)
- drug adverse effects of antihypertensive agents
Drug interactions
- diltiazem increases digoxin levels
- coadministration of beta-adrenergic receptor antagonists intensifies negative inotropic effects
- diltiazem inhibits cyt CYP3A4, thus inhibits its own metabolism & metabolism of other CYP3A4 substrates
- concurrent administration of fentanyl may result in severe hypotension
- cimetidine increases diltiazem levels
- diltiazem decreases lithium levels
- pharmacologic effects of theophylline may be enhanced
- among elderly with atrial fibrillation anticoagulated with apixaban or rivaroxaban, rate control with diltiazem is associated with a higher risk of serious bleeding vs rate control with metoprolol[1]
- any drug that inhibits CYP3A4 may increase levels of diltiazem
- any drug that induces CYP3A4 may diminish levels of diltiazem
- drug interaction(s) of antiarrhythmic agents in combination with diuretics
- drug interaction(s) of diltiazem with rivaroxaban
- drug interaction(s) of diltiazem with apixaban
- drug interaction(s) of calcium channel blockers with ARBs
- drug interaction(s) of calcium channel blockers with ACE inhibitors
- drug interaction(s) of calcium channel blockers with diuretics
- drug interaction(s) of calcium channel blockers with erythromycin
- drug interaction(s) of calcium channel blockers with clarithromycin
- drug interaction(s) of renin-angiotensin-aldosterone inhibitors with SGLT-2 inhibitor
- drug interaction(s) of renin-angiotensin-aldosterone inhibitors with trimethoprim-sulfamethoxazole
- drug interaction(s) of beta-adrenergic receptor antagonists with calcium channel blockers
- drug interaction(s) of NSAIDs & antihypertensives
Laboratory
Mechanism of action
- inhibits L-type Ca+2 channels
- dilates coronary arteries & arterioles & increases myocardial oxygen delivery
- decreased total peripheral vascular resistance
- decreases AV node automaticity & AV node conduction
- negative inotropic agent (less so than verapamil)
- decreases renal glomerular pressure by efferent arteriolar dilatation, thus diminishing proteinuria[2]
* see Brand names for drugs in different countries
More general terms
Additional terms
- Brand names for drugs in different countries
- cytochrome P450 3A4 (cytochrome P450 C3, nifedipine oxidase, P450-PCN1, NF-25, CYP3A4)
- L-type Ca+2 channel, long duration or slowly inactivating Ca+2 channel or dihydropyridine receptor (R-type Ca+2 channel)
Component of
References
- ↑ 1.0 1.1 The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ 2.0 2.1 Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
- ↑ Kaiser Permanente Northern California Regional Drug Formulary, 1998
- ↑ Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
- ↑ Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995
- ↑ Department of Veterans Affairs, VA National Formulary
- ↑ 7.0 7.1 Prescriber's Letter 10(4):21 2003
- ↑ 8.0 8.1 Prescriber's Letter 11(2):suppl 2004
- ↑ Ray WA, Chung CP, Stein CM et al. Serious bleeding in patients with atrial fibrillation using diltiazem with apixaban or rivaroxaban. JAMA 2024 Apr 15:e243867 [e-pub]. PMID: https://pubmed.ncbi.nlm.nih.gov/38619832 https://jamanetwork.com/journals/jama/fullarticle/2817546
- ↑ 10.0 10.1 10.2 Az A, Sogut O, Dogan Y et al. Reducing diltiazem-related hypotension in atrial fibrillation: Role of pretreatment intravenous calcium. Am J Emerg Med 2025 Feb; 88:23. PMID: https://pubmed.ncbi.nlm.nih.gov/39577214 https://www.sciencedirect.com/science/article/abs/pii/S0735675724006119
Database
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=62920
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=39186
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=3076
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=3075
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=3037122
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=657259