The effects of Cassia auriculata and Cardiospermum halicacabum teas on the steady state blood level and toxicity of carbamazepine.

A study was conducted using male Wistar rats as the experimental model, to compare the effects of concurrent administration of herbal tea prepared from dried flowers of Cassia auriculata or aerial parts of Cardiospermum halicacabum and carbamazepine, on (a). steady state serum levels of the prescription drug, and (b). changes in toxicity (as assessed by changes in general behaviour, haematological parameters, and liver and kidney function) that may occur due to drug interaction. Results demonstrate that in rats receiving the Cassia auriculata tea and carbamazepine, the blood levels of the prescription drug were significantly enhanced by 47.1% (P<0.04), when compared with the levels in animals receiving only carbamazepine for the same time period, with no apparent changes in toxicity. In animals receiving the Cardiospermum halicacabum tea, there were no significant changes in the blood levels of carbamazepine or drug-related toxicity. Cassia auriculata tea has therefore the potential to influence the bioavailability of carbamazepine, and hence its therapeutic actions. Concurrent ingestion of carbamazepine with herbal teas containing Cassia auriculata is therefore best avoided by patients under treatment for epilepsy.