BACLOFEN
- Action to be taken: Caution with close monitoring.
- Rationale: About 15% of a dose of baclofen is metabolised in the liver. Deamination yields the main metabolite, chlorophenyl-hydroxybutyric acid, which is pharmacologically inactive. Increased sedation may occur when Lioresal is taken concomitantly with other drugs causing CNS depression including other muscle relaxants (such as tizanidine), with synthetic opiates or with alcohol. The risk of respiratory depression is also increased. In addition, hypotension has been reported with concomitant use of morphine and intrathecal baclofen. Careful monitoring of respiratory and cardiovascular functions is essential, especially in patients with cardiopulmonary disease and respiratory muscle weakness
- Action to be taken: Caution with close monitoring.
- Rationale:Dantrium is probably metabolized by hepatic microsomal enzymes, enhancement of its metabolism by other drugs is possible. In vitro studies have shown that cannabis is a weak inhibitor of CYP enzymes, hence it may impact dantrolene metabolism. Furthermore, drowsiness may occur with Dantrium therapy, and the concomitant administration of CNS depressants such as sedatives and tranquilizing agents may result in further drowsiness.
References
- Lioresal (baclofen) package insert. Novartis Pharmaceuticals Canada Inc, Dorval, Quebec 2017
- Dantrium (dantrolene) package instert. JHP Pharmaceuticals, LLC. Rochester, MI 2011
- Watanabe K, Yamaori S, Funahashi T, et al. Cytochrome P450 enzymes involved in the metabolism of tetrahydrocannabinols and cannabinol by human hepatic microsomes. Life Sci. 2007;80:1415-1419.
- Stout SM, Cimino NM. Exogenous cannabinoids as substrates, inhibitors, and inducers of human drug metabolizing enzymes: a systematic review. Drug Metab Rev. 2014;46:86-95.