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Diltiazem
Aka: Diltiazem, Cardizem, Benzothiazapine, Cartia, Taztia, Tiazac
- See Also
- Calcium Channel Blocker
- Calcium Channel Blocker Overdose
- Dihydropyridine Calcium Channel Blocker (e.g. Amlodipine, Nifedipine)
- Verapamil
- Mibefradil
- Class
- Non-Dihydropyridine Calcium Channel Blocker
- Precautions
- Write for generic Diltiazem ER to allow pharmacist to substitute between multiple similar ER preparations
- (2016) Presc Lett 23(7): 39-40
- Mechanism
- AV Node effects
- Slow AV Node Conduction
- Prolong AV Node refractory period
- Less negative hemodynamic effects than Verapamil
- Potent negative chronotropic effect
- Minimal negative inotropic effect
- Diltiazem effects Left Ventricular Dysfunction less
- Coronary vasodilatation
- Pharmacokinetics
- Onset in 2-7 minutes after IV infusion
- Contraindications
- Wolff-Parkinson-White Syndrome with Atrial Fibrillation
- Paroxysmal accelerated ventricular response
- Risk of progression into Ventricular Fibrillation
- Wide Complex Tachycardia (unless supraventricular)
- Risk of severe Hypotension
- May progress into Ventricular Fibrillation
- Sinus Node or AV Node dysfunction without Pacemaker
- AV Block
- Sick Sinus Syndrome
- Severe Congestive Heart Failure
- Concurrent Intravenous Beta Blocker use
- Indications
- Atrial Fibrillation with Rapid Ventricular Response
- Highly effective at controlling ventricular rate
- Paroxysmal Supraventricular Tachycardia
- Less studied than Verapamil for PSVT
- Supraventricular Tachycardia
- Terminates AV Node reentry Tachycardias
- Hypertension
- Dosing: Rapid Atrial Fibrillation or PSVT
- Regimen 1: One Bolus and then maintenance
- Bolus: 0.25 mg/kg (to 20 mg) IV over 2 minutes
- Maintenance: 10 mg/hour titrated to Heart Rate (typically 5-15 mg/hour)
- Mnemonic: Rule of 15 for patient weight of 70 kg
- First: 15 mg IV over 2 minutes, then infusion at 15 mg/hour
- Regimen 2: Two boluses and then maintenance
- Bolus One: 0.25 mg/kg (to 20 mg) IV over 2 minutes
- Bolus Two: 0.35 mg/kg (to 25 mg) IV over 2 minutes starting 15 minutes after first bolus
- Maintenance: 10 mg/hour titrated to Heart Rate (typically 5-15 mg/hour)
- Regimen 3: Hypotensive patient
- "Bolus": 2.5 mg/min over 10-20 min infusion
- http://ehced.org/wp-content/site/Drips/dilt-load.pdf
- Maintenance: 5 mg/hour titrated as Blood Pressure allows to Heart Rate (typically 5-15 mg/hour)
- Pretreating with Calcium is unlikely to benefit Blood Pressure
- At best may offer transient Blood Pressure increase for 10 minutes (secondary to Catecholamine surge)
- Calcium infusion could be considered in Hypocalcemia (e.g. Calcium Chloride 0.5 to 1 g IV)
- Kolkebeck (2004) J Emerg Med 26(4): 395-400 [PubMed]
- Oral dosing after intravenous rate control
- Consider Beta Blocker for chronic rate control (more efficacious than oral Diltiazem)
- Diltiazem regular 30-60 mg orally four times daily as a start (titrating to 120 to 360 mg daily)
- Dosing: Hypertension
- Regular: 30 mg orally four times daily (MAX 360 mg/day)
- Extended: 180-240 mg orally daily (MAX 540 mg/day)
- Adverse Effects
- See Calcium Channel Blocker