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.