Xenical Drug Interactions

No interactions based on specific drug-drug interaction studies with amitriptyline, atorvastatin, biguanides, digoxin, fibrates, fluoxetine, losartan, phenytoin, oral contraceptives, phentermine, pravastatin, warfarin, nifedipine gastrointestinal therapeutic system (GITS), nifedipine slow release, sibutramine or alcohol have been observed.
However, when warfarin or other oral anticoagulants are given in combination with orlistat, international normalised ratio (INR) values should be monitored.
Decreases in the absorption of vitamins D and E, and β-carotene have been observed when co-administered with Xenical. If a multivitamin supplement is recommended, it should be taken at least 2 hrs after the administration of Xenical or at bedtime.
A reduction in cyclosporin plasma levels has been observed when Xenical is co-administered (see Precautions). Therefore, it is recommended to monitor more frequently than usual the cyclosporin plasma levels when Xenical is co-administered (see Precautions).
In a PK study, oral administration of amiodarone during orlistat treatment demonstrated a 25-30% reduction (see Precautions) in the systemic exposure to amiodarone and desethylamiodarone. Due to the complex pharmacokinetics of amiodarone, the clinical effect of this is unclear. The effect of commencing orlistat treatment in patients on stable amiodarone therapy has not been studied. A reduced therapeutic effect of amiodarone is possible.
Convulsions have been reported in patients treated concomitantly with Xenical and antiepileptic drugs. A causal relationship has not been established, however, patients should be monitored for possible changes in the frequency and/or severity of convulsions.
Incompatibilities: Not applicable.