Drug Interactions 57
Drug affected Drug interacting Effect
C. Psychotropic drugs
Hypnotics & sedatives Alcohol, antidepressants, Potentiation.
antihistaminics, narcotic
analgesics
Tricyclic anti- Alcohol Potentiation of sedative effect.
depressants Oral contraceptives Reduced effect.
Phenothiazine derivatives Increased side effects.
Imipramine Cimetidine Potentiation.
Lithium Diuretics, diclofenac, indomethacin, Potentiation.
phenylbutazone
Acetazolamide, aminophylline, sodium Increased lithium excretion.
bicarbonate
Haloperidol Increased risk of extra pyramidal
effects.
Endocrine system
Antidiabetic drugs Alcohol Antabuse like reaction.
Beta-adrenoceptor blocking drugs, Potentiation.
MAO inhibitors
Corticosteroids, corticotrophin, diazo- Antagonism.
xide, diuretics (bumetanide, furosemide,
thiazides), oral contraceptives
Metformin Alcohol Increased risk of lactic acidosis.
Corticosteroids, cortico- Diuretics (bumetanide, ethacrynic acid, Increased potassium loss.
trophin furosemide, thiazides)
Cortisone, dexamethasone, Barbiturates, carbamazepine, Reduced effect.
hydrocortisone, predni- phenytoin, primidone, rifampicin
solone, prednisone.
Gynaecology
Oral contraceptives Barbiturates, carbamazepine, dichloral- Reduced effect.
phenazone, phenytoin, primidone,
rifampicin.
Oral antibiotics such as ampicillin, Reduced effect.
tetracycline