Diltiazem

Aka: Diltiazem, Cardizem, Benzothiazapine, Cartia, Taztia, Tiazac

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II. Precautions

  1. Write for generic Diltiazem ER to allow pharmacist to substitute between multiple similar ER preparations
    1. (2016) Presc Lett 23(7): 39-40

III. Mechanism

  1. Non-Dihydropyridine Calcium Channel Blocker
  2. AV Node effects
    1. Slow AV Node Conduction
    2. Prolong AV Node refractory period
  3. Less negative hemodynamic effects than Verapamil
    1. Potent negative chronotropic effect with decreased Heart Rate (but less than with Verapamil)
    2. Minimal negative inotropic effect
    3. Decreases Afterload via peripheral arterial vasodilation
    4. Diltiazem affects Left Ventricular Dysfunction less than Verapamil
  4. Coronary vasodilatation
    1. Prevents sympathetic induced Coronary Artery spasm
    2. May reduce Anginal episodes and increase Exercise tolerance in Stable Angina

IV. Indications

  1. Hypertension
    1. Consider Dihydropyridine Calcium Channel Blocker (e.g. Amlodipine) instead if Heart Rate control not needed
  2. Atrial Fibrillation with Rapid Ventricular Response
    1. Highly effective at controlling ventricular rate
  3. Paroxysmal Supraventricular Tachycardia
    1. Less studied than Verapamil for PSVT
  4. Supraventricular Tachycardia
    1. Terminates AV Node reentry Tachycardias

V. Contraindications

  1. Wolff-Parkinson-White Syndrome with Atrial Fibrillation
    1. Paroxysmal accelerated ventricular response
    2. Risk of progression into Ventricular Fibrillation
  2. Wide Complex Tachycardia (unless supraventricular)
    1. Risk of severe Hypotension
    2. May progress into Ventricular Fibrillation
  3. Sinus Node or AV Node dysfunction without Pacemaker
    1. AV Block
    2. Sick Sinus Syndrome
  4. Severe Congestive Heart Failure or pulmonary congestion
  5. Concurrent Intravenous Beta Blocker use
  6. Hypotension

VI. Dosing: Rapid Atrial Fibrillation or PSVT

  1. Regimen 1: One Bolus and then maintenance
    1. Bolus: 0.25 mg/kg (to 20 mg) IV over 2 minutes
    2. Maintenance: 10 mg/hour titrated to Heart Rate (typically 5-15 mg/hour)
    3. Mnemonic: Rule of 15 for patient weight of 70 kg
      1. First: 15 mg IV over 2 minutes, then infusion at 15 mg/hour
      2. Titrate dosing between 5 to 15 mg/hour
  2. Regimen 2: Two boluses and then maintenance
    1. Bolus One: 0.25 mg/kg (to 20 mg) IV over 2 minutes
    2. Bolus Two: 0.35 mg/kg (to 25 mg) IV over 2 minutes starting 15 minutes after first bolus
    3. Maintenance: 10 mg/hour titrated to Heart Rate (typically 5-15 mg/hour)
  3. Regimen 3: Hypotensive patient
    1. "Bolus": 2.5 mg/min over 10-20 min infusion
      1. http://ehced.org/wp-content/site/Drips/dilt-load.pdf
    2. Maintenance: 5 mg/hour titrated as Blood Pressure allows to Heart Rate (typically 5-15 mg/hour)
    3. Pretreating with Calcium is unlikely to benefit Blood Pressure
      1. At best may offer transient Blood Pressure increase for 10 minutes (secondary to Catecholamine surge)
      2. Calcium infusion could be considered in Hypocalcemia (e.g. Calcium Chloride 0.5 to 1 g IV)
      3. Kolkebeck (2004) J Emerg Med 26(4): 395-400 [PubMed]
  4. Oral dosing after intravenous rate control
    1. Consider switching to Beta Blocker for chronic rate control (more efficacious than oral Diltiazem)
    2. Diltiazem regular release starting at 30-60 mg orally three to four times daily
      1. Titrate 120 to 360 mg orally daily with extended release

VII. Dosing: Hypertension in Adults

  1. Regular Release
    1. Start 30 mg orally three times times daily
    2. Maximum 360 mg/day
  2. Extended Release
    1. Long-acting formulations have variable release mechanisms and dosing regimens vary between products
      1. Extended Release (XR, XT, CD) formulations are dosed once daily
      2. Sustained Release (SR) formulations are dosed twice daily
      3. Extended release capsule contents may be sprinkled on food
    2. Start 120-240 mg orally daily
    3. Target: 240 to 360 mg/day
    4. Maximum: 540 mg/day

VIII. Dosing: Hypertension in Children (Not FDA approved)

  1. Regular Release
    1. Start 1.5 to 2 mg/kg/day orally divided 3 to 4 times daily
    2. Maximum 3.5 mg/kg/day

IX. Adverse Effects

  1. See Calcium Channel Blocker
  2. Peripheral Edema
  3. Dizziness
  4. Headache
  5. Nausea
  6. Rash
  7. Asthenia
  8. Bradycardia

X. Pharmacokinetics

  1. Onset in 2-7 minutes after IV infusion
  2. Bioavailability 50% after oral dose
  3. Protein bound 75%
  4. Half-Life 3 hours with active metabolites

XI. Metabolism

  1. Decrease dose in renal disease
  2. Accumulation risk with liver Impairment

XII. Drug Interactions

  1. Agents that prolong AV Node conduction (avoid)
    1. Beta Blockers
    2. Digoxin
    3. Clonidine (case reports of severe episodes)
    4. Ivabradine (contraindicated in combination)
  2. Agents that have levels increased by Diltiazem
    1. Propranolol
    2. Buspirone
    3. Lovastatin (limit to 20 mg daily)
    4. Simvastatin (limit to 10 mg daily)
    5. Quinidine
  3. Agents that increase Diltiazem Levels
    1. Cimetidine

XIII. Safety

  1. Pregnancy Category C
  2. Safe in Lactation

XIV. Resources

  1. Diltiazem Tablet Extended Release (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=56573e9d-7bd2-694c-cd6d-26039590e548
  2. Diltiazem Injection Solution (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=5e36488b-8f2d-4dc9-b803-af1829e6fdd0

XV. References

  1. (2022) Presc Lett 29(11): 64-5
  2. (2022) Presc Lett, Resource #381108, Comparison of Calcium Channel Blockers
  3. (2020) Med Lett Drugs Ther 62(1598): 73-80
  4. Olson (2020) Clinical Pharmacology, Medmaster Miami, p. 70-1
  5. Hamilton (2020) Tarascon Pocket Pharmacopoeia

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Related Studies

Cost: Medications

diltiazem (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
DILTIAZEM 120 MG TABLET Generic $0.28 each
DILTIAZEM 12HR ER 120 MG CAP Generic $3.33 each
DILTIAZEM 12HR ER 60 MG CAP Generic $2.03 each
DILTIAZEM 12HR ER 90 MG CAP Generic $2.31 each
DILTIAZEM 24H ER(CD) 120 MG CP Generic $0.14 each
DILTIAZEM 24H ER(CD) 180 MG CP Generic $0.20 each
DILTIAZEM 24H ER(CD) 240 MG CP Generic $0.24 each
DILTIAZEM 24H ER(CD) 300 MG CP Generic $0.30 each
DILTIAZEM 24H ER(CD) 360 MG CP Generic $0.66 each
DILTIAZEM 24H ER(LA) 120 MG TB Generic $2.26 each
DILTIAZEM 24H ER(LA) 180 MG TB Generic $2.08 each
DILTIAZEM 24H ER(LA) 240 MG TB Generic $2.23 each
DILTIAZEM 24H ER(LA) 300 MG TB Generic $3.12 each
DILTIAZEM 24H ER(LA) 360 MG TB Generic $3.12 each
DILTIAZEM 24H ER(XR) 120 MG CP Generic $0.44 each
DILTIAZEM 24H ER(XR) 180 MG CP Generic $0.53 each
DILTIAZEM 24H ER(XR) 240 MG CP Generic $0.75 each
DILTIAZEM 24HR ER 120 MG CAP Generic $0.26 each
DILTIAZEM 24HR ER 180 MG CAP Generic $0.29 each
DILTIAZEM 24HR ER 240 MG CAP Generic $0.48 each
DILTIAZEM 24HR ER 300 MG CAP Generic $0.59 each
DILTIAZEM 24HR ER 360 MG CAP Generic $0.56 each
DILTIAZEM 24HR ER 420 MG CAP Generic $0.95 each
DILTIAZEM 30 MG TABLET Generic $0.09 each
DILTIAZEM 60 MG TABLET Generic $0.17 each
DILTIAZEM 90 MG TABLET Generic $0.24 each
cardizem (on 2/23/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
CARDIZEM LA 120 MG TABLET $3.66 each
cartia (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
CARTIA XT 120 MG CAPSULE Generic $0.14 each
CARTIA XT 180 MG CAPSULE Generic $0.20 each
CARTIA XT 240 MG CAPSULE Generic $0.24 each
CARTIA XT 300 MG CAPSULE Generic $0.30 each
taztia (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
TAZTIA XT 120 MG CAPSULE Generic $0.26 each
TAZTIA XT 180 MG CAPSULE Generic $0.29 each
TAZTIA XT 240 MG CAPSULE Generic $0.48 each
TAZTIA XT 300 MG CAPSULE Generic $0.59 each
TAZTIA XT 360 MG CAPSULE Generic $0.56 each
FPNotebook does not benefit financially from showing this medication data or their pharmacy links. This information is provided only to help medical providers and their patients see relative costs. Insurance plans negotiate lower medication prices with suppliers. Prices shown here are out of pocket, non-negotiated rates. See Needy Meds for financial assistance information. GoodRx is another tool for finding lower drug prices.

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