Tell the doctor if patient is taking any of the following: rifampicin or rifabutin (antibiotics); hydrochlorothiazide (used to remove excess water from the body and help reduce blood pressure); warfarin or coumarin anticoagulant drugs (used to prevent blood clots); benzodiazepines (used to treat anxiety and to help patient sleep) e.g. diazepam or midazolam; oral sulphonylureas (used to control diabetes) e.g. glibenclamide, chlorpropamide, glipizide or tolbutamide; phenytoin (used to control epilepsy); cyclosporin or tacrolimus (used to reduce the effect of the immune system e.g. to prevent the rejection of an organ transplant or graft); theophylline (used to increase the air flow to the lungs and improve breathing); zidovudine (used in HIV-positive patients); astemizole (an antihistamine); any other medicines.