MONTELUKAST AND PHENOBARBITAL

Phenobarbital reduces the AUC and maximum serum levels of montelukast by 38% and 20%, respectively. However, there is so far no clinical evidence that the montelukast dosage needs adjustment. Note that primidone is metabolised to phenobarbital and therefore may interact similarly.
The manufacturers caution concurrent use, especially in children. Monitor for a reduction in montelukast efficacy.