Montelukast Phenobarbital

Drugs that may interact with montelukast include phenobarbital and prednisone. 

Clinically important, potentially hazardous interactions with aluminum, aminophylline, aspirin, chlorambucil, cimetidine, clarithromycin, cyclophosphamide, cyclosporine, dicumarol, diuretics, docetaxel, estrogens, grapefruit juice, indomethacin, influenza vaccines, itraconazole, ketoconazole, lansoprazole, live vaccines, methotrexate, montelukast, omeprazole, oral contraceptives, pancuronium, phenobarbital, phenytoin, ranitidine, rifampicin, rifampin, timolol, tolbutamide, vitamin A... 

Phenobarbital modestly reduces montelukast levels, but this is not thought to be clinically significant. Phenytoin is predicted to interact similarly. 

Montelukast 10 mg was given to 14 healthy subjects before and after they took phenobarbital 100 mg daily for 14 days. It was found that the geo-... 

The manufacturers of montelukast caution its use with inducers of the cytochrome P450 isoenzyme CYP3A4, such as rifampicin, especially in children. This is because phenobarbital (an inducer of CYP3A4) has been found to reduce the AUC and serum levels of montelukast. However, there is currently no clinical evidence that the montelukast dosage needs adjustment in patients taking rifampicin. 

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