Diltiazem

Diltiazem

[30mg tablets 5 cents]

ADMINISTRATION ROUTES:

  • PO, NG

ALTERNATIVE NAMES:

  • Dilzem, Cardizem

ICU INDICATIONS:

  1. rate control in atrial fibrillation
  2. angina

PRESENTATION AND ADMINISTRATION:

  • PO:
    Immediate Release Tablets:

    Dilzem 30mg tablets (white), Dilzem 60mg tablets (white)
    Twice Daily Sustained Release Capsules:

    Dilzem SR 90mg capsules (green/white), Dilzem SR 120mg capsules (medium brown / light brown)
    Once Daily Long Acting Tablets and Controlled Delivery Capsules:
    Dilzem LA 180mg tablets (white), Dilzem LA 240mg tablets (white), Cardizem CD 120mg tablets (light turquoise / opaque), Cardizem CD 180mg tablets (light turquoise blue/ blue), Cardizem CD 240mg tablets (blue)

DOSAGE:

  • PO / NG:
    In ICU it is usually appropriate to commence with 30mg 6-8 hourly and to increase as required to up to 360mg a day in divided doses. Immediate release tablets are the only formulation that can be administered via a nasogastric tube.

    Note: dosage errors with diltiazem are common due to the variety of formulations that exist. Always make sure you are administering the correct formulation (see PRESENTATION AND ADMINISTRATION)

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

  • Dose as in normal renal function

DOSAGE IN PAEDIATRICS:

  • PO:
    Use Immediate Release Only 1mg/kg 8 hourly; increase to maximum of 3mg/kg 8 hourly as required

CLINICAL PHARMACOLOGY:

  • Calcium channel blocker

CONTRAINDICATIONS

  1. sick sinus syndrome except in the presence of a functioning ventricular pacemaker
  2. patients with second- or third-degree AV block except in the presence of a functioning ventricular pacemaker
  3. hypotension
  4. hypersensitivitytothediltiazem

WARNINGS

  • Hypotension:
    Decreases in blood pressure associated with Diltiazem therapy may occasionally result in symptomatic hypotension.
  • Acute Hepatic Injury:
    Mild elevations of transaminases with and without concomitant elevation in alkaline phosphatase and bilirubin have been observed in clinical studies. Such elevations were usually transient and frequently resolved even with continued diltiazem treatment. In rare instances, significant elevations in enzymes such as alkaline phosphatase, LDH, ALT, AST, and other phenomena consistent with acute hepatic injury have been noted.

PRECAUTIONS

  • General:
    See WARNINGS
  • Laboratory Tests:
    No tests in addition to routine ICU tests are indicated
  • Drug/Laboratory Test Interactions:
    None if note

IMPORTANT DRUG INTERACTIONS FOR THE ICU

  • Due to the potential for additive effects, caution and careful titration are warranted in patients receiving diltiazem concomitantly with other agents known to affect cardiac contractility and/or conduction.
  • Concomitant administration of diltiazem with carbamazepine has been reported to result in elevated serum levels of carbamazepine (40-72% increase), resulting in toxicity in some cases.
  • A pharmacokinetic interaction between diltiazem and cyclosporine has been observed during studies involving renal and cardiac transplant patients. In renal and cardiac transplant recipients, a reduction of cyclosporine dose ranging from 15-48% was necessary to maintain cyclosporine trough concentrations similar to those seen prior to the addition of diltiazem. If these agents are to be administered concurrently, cyclosporine concentrations should be monitored, especially when diltiazem therapy is initiated, adjusted, or discontinued.
  • Coadministration of rifampin with diltiazem lowered the diltiazem plasma concentrations to undetectable levels. Coadministration of diltiazem with rifampin should be avoided when possible, and alternative therapy considered.

ADVERSE REACTIONS

  • Cardiovascular:
    Oedema, angina, arrhythmia, AV block (second- or third-degree), bundle branch block, congestive heart failure, ECG abnormalities, hypotension, palpitations, syncope, tachycardia, ventricular extrasystoles.
  • Nervous System:
    Headache, abnormal dreams, amnesia, depression, gait abnormality, hallucinations, insomnia, nervousness, paresthesia, personality change, somnolence, tinnitus, tremor.
  • Gastrointestinal:
    Nausea, anorexia, constipation, diarrhoea, dry mouth, dysgeusia, dyspepsia, mild elevations of SGOT, SGPT, LDH, and alkaline phosphatase, thirst, vomiting, weight increase.
  • Dermatologic:
    Rash, petechiae, photosensitivity, pruritus, urticaria.

Critical Care Drug Manual

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