OBJECT DRUGS
Vinca Alkaloids:
- Vinblastine (Velban)
- Vincristine (Oncovin)
- Vinorelbine (Navelbine)
PRECIPITANT DRUGS
Calcium Channel Blockers:
- Diltiazem (Cardizem, etc.)
- Nicardipine (Cardene, etc.)
- Nifedipine (Procardia, etc.)
- Verapamil (Isoptin, etc.)
Comment:
Vinca alkaloids appear to be metabolized by CYP3A4 and reports have described severe toxicity in patients receiving CYP3A4 inhibitors such as verapamil. P-glycoprotein inhibition may also be involved in these interactions.
Class 2: Use Only if Benefit Felt to Outweigh Risk
- Use Alternative: Use an alternative to the enzyme inhibitor if possible.
- Calcium channel blockers: Calcium channel blockers other than diltiazem, nicardipine, nifedipine, and verapamil are unlikely to inhibit the metabolism of vinca alkaloids.
- Monitor: Monitor for toxicity from vincristine (primarily peripheral neuropathy symptoms: paresthesias, neuritic pain, muscle pain, constipation sometimes progressing to paralytic ileus) or vinblastine and vinorelbine (primarily bone marrow suppression).