No data supporting capacity for CYP-induction. Found to be weak CYP-inhibitor in in-vitro studies, but the concentration needed to inhibit is much higher than reached during therapy. Relatively low hepatic exposure. Side effects such as nausea and vomiting may be potentially porphyrinogenic through reduction in caloric intake.

Vincristine sulfate is the sulfate of an alkaloid, 22-oxovincaleukoblastine, obtained from Catharanthus roseus (Vinca rosea) (Apocynaceae). Very hygroscopic, freely soluble in water.

Vincristine is an antineoplastic agent that may act similarly to vinblastine. It is used in combination chemotherapy in the treatment of leukaemia, malignant lymphoma, lungcancer. Administered as intravenous injection or infusion. Adverse reactions of vincristine that can be confused with an acute porphyric attack are abdominal pain, obstipation and paralytic ileus, peripheral neuropathy, hyponatremia, constipation, nausea, vomiting and diarrhoea. Side effects such as nausea and vomiting may be potentially porphyrinogenic through reduction in caloric intake.

How vincristine is metabolised has not been clearly determined, but CYP 3A4 probably takes part in its metabolism. Listed as substrate and inhibitor of CYP 3A4 by Rendic (2002) and Zhou (2007). Found to be a weak inhibitor of CYP 3A4 by Baumhakel et al (2001). However, the concentration needed to inhibit is much higher than those reached during therapy. Not listed as CYP-inducer or inhibitor by Flockhart (2007). No clear observations of interference with CYP-metabolism of other drugs. Eighty percent of the dose is recovered in faeces, 10 percent in urine.

Reports of uneventful use: Samuels (1984) reported uneventful use of vincristine in two female PV-patients.

No.