ADMINISTRATION ROUTES:
PO, NG
ALTERNATIVE NAMES:
Dilzem, Cardizem
ICU INDICATIONS:
- Rate control in atrial fibrillation
- Angina
PRESENTATION AND ADMINISTRATION:
PO:
Immediate Release Tablets
Dilzem 30 mg tablets (white), Dilzem 60 mg tablets (white)
Twice Daily Sustained Release Capsules
Dilzem SR 90 mg capsules (green/white), Dilzem SR 120 mg capsules (medium brown / light brown)
Once Daily Long Acting Tablets and Controlled Delivery Capsules
Dilzem LA 180 mg tablets (white), Dilzem LA 240 mg tablets (white), Cardizem CD 120 mg tablets (light turquoise / opaque), Cardizem CD 180 mg tablets (light turquoise blue/ blue), Cardizem CD 240 mg tablets (blue)
DOSAGE:
PO / NG:
30 mg 6-8 hourly
Increase as required to 360 mg total per day, given in divided doses
Only immediate release tablets are the only formulation that can be administered through a nasogastric tube
Note: dosage errors with diltiazem are common due to the variety of formulations that exist. Always check 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
1 mg/kg TDS
Increase as required to maximum 3 mg/kg TDS
CLINICAL PHARMACOLOGY:
Calcium channel blocker
CONTRAINDICATIONS:
- Sick sinus syndrome except in the presence of a functioning ventricular pacemaker
- Patients with second- or third-degree AV block except in the presence of a functioning ventricular pacemaker
- Hypotension
- Hypersensitivity to diltiazem
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 of note
IMPORTANT DRUG INTERACTIONS IN 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 cyclosporin has been observed during studies involving renal and cardiac transplant patients. In renal and cardiac transplant recipients, a reduction of cyclosporin dose ranging from 15-48% was necessary to maintain cyclosporin trough concentrations similar to those seen prior to the addition of diltiazem. If these agents are to be administered concurrently, cyclosporin concentrations should be monitored, especially when diltiazem therapy is initiated, adjusted, or discontinued.
Co-administration of rifampin with diltiazem lowered the diltiazem plasma concentrations to undetectable levels. Co-administration 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, paraesthesia, 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