Basic Information
ID DDInter473 and DDInter1160
Interaction The use of estrogens may potentiate the risk of hepatotoxicity associated with dantrolene therapy. The mechanism of interaction is unknown. Fatal and non-fatal liver disorders of an idiosyncratic or hypersensitivity nature have been reported during dantrolene use.
Management Dantrolene should be used with caution in patients, particularly females over 35 years of age, who are receiving concomitant estrogen therapy. Liver function tests (SGOT, SGPT, alkaline phosphatase, total bilirubin) should be performed prior to and during dantrolene therapy at appropriate intervals, and the drug should generally be withheld if significant abnormalities are observed. Patients treated with dantrolene should be advised to promptly contact their physician if they develop signs and symptoms of hepatocellular injury such as fever, rash, anorexia, nausea, vomiting, fatigue, right upper quadrant pain, dark urine, and jaundice. The drug should be discontinued if hepatitis is suspected, since early detection and drug withdrawal will increase the likelihood of reversing the damage. Following resolution of clinical and laboratory abnormalities, reinstitution of dantrolene therapy should be attempted with extreme caution and only if benefit clearly outweighs the risk.
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Alternative for Dantrolene -
Alternative for Mestranol -
Potential Metabolism Interactions
Substrate-Substrate Interaction：If more than one drug is metabolized by the same CYP, it is possible that its metabolism is inhibited because of the competition between the drugs. That means, it can be useful to lower the dosage of the drugs in the drug-cocktail because they remain longer in the organism than in monotherapy.
Inhibitor-Inhibitor Interaction：Combining two or more inhibitors of one CYP, should be compensated by lowering the dosage of these drugs because the metabolism is reduced and the drugs remain longer in the organism than in monotherapy. Not adapting the dosage bears the risk of even more side effects.
Inhibitor-Substrate Interaction：Combining drugs that have inhibitory effect and are substrates of one particular CYP, should be compensated by lowering the dosage. They rest longer in the organism than in monotherapy. Not adapting the dosage bears the risk of even more side effects.