Topoccord 1/Topoccord 4 Drug Interactions

No in vivo human pharmacokinetic interaction studies have been performed.
Topotecan does not inhibit human P450 enzymes (see Pharmacology: Pharmacokinetics under Actions). In a population study using the intravenous route, the co-administration of granisetron, ondansetron, morphine or corticosteroids did not appear to have a significant effect on the pharmacokinetics of total topotecan (active and inactive form).
When combining topotecan with other chemotherapy agents, reduction of the doses of each medicinal product may be required to improve tolerability. However, when combining with platinum agents, there is a distinct sequence-dependent interaction depending on whether the platinum agent is given on day 1 or 5 of the topotecan dosing. If either cisplatin or carboplatin is given on day 1 of the topotecan dosing, a lower dose of each agent must be given to improve tolerability compared to the dose of each agent which can be given if the platinum agent is given on day 5 of the topotecan dosing.
When topotecan (0.75 mg/m²/day for 5 consecutive days) and cisplatin (60 mg/m²/day on Day 1) were administered in 13 patients with ovarian cancer, a slight increase in AUC (12%, n=9) and C_max (23%, n=11) was noted on day 5. This increase is considered unlikely to be of clinical relevance.