Inductors of microsomal oxidation in the liver (phenytoin, ethanol, barbiturates, flumecinol, rifampicin, phenylbutazone, tricyclic antidepressants) increase the production of hydroxylated active metabolites of paracetamol, which allows the development of severe intoxication with small overdoses.
Long-term use of barbiturateseffectiveness of paracetamol.
Inhibitors of microsomal oxidation (incl. cimetidine) reduce the risk of hepatotoxic effects of paracetamol and enhance the pressor effect and the arrhythmogenic effect of phenylephrine.
When taken together with a non-steroidal anti-inflammatory drugagents and salicylates The nephrotoxic effect of paracetamol increases.
Diflunisal increases the plasma concentration of paracetamol by 50%, which increases the risk of hepatotoxicity.
Simultaneous use with ethanol increases the risk of acute pancreatitis. Paracetamol enhances the effect of anticoagulants of indirect action and reduces the effectiveness of uricosuric drugs. Paracetamol enhances the effects of monoamine oxidase inhibitors, sedatives, alcohol.
Phenylephrine reduces the hypotensive effect of nitrates, diuretics and hypotensive drugs (including methyldopy, mekamilamin, guanadrel, guanetidine). Antidepressants, antiparkinsonian, antipsychotic drugs, phenothiazine derivatives - the risk of urinary retention, dry mouth, constipation against the background of the use of phenylephrine.Glucocorticosteroids - the risk of developing glaucoma with the simultaneous use of phenylephrine. Guanethidine increases alpha-adrenomimetic, and tricyclic antidepressants - the sympathomimetic effect of phenylephrine.
Ergometrine, ergotamine, methylergomethrin, oxytocin, doxapram increase the severity of the vasoconstrictor effect of phenylephrine. Inhalation anesthetics (including chloroform, enflurane, halothane, isoflurane, methoxyflurane) increase the risk of severe atrial and ventricular arrhythmias. Thyroid hormones increase (mutually) the effect of phenylephrine and the associated risk of coronary insufficiency (especially in coronary atherosclerosislerosis).
Beta-adrenoblockers reduce the cardiostimulating activity of phenylephrine, against the background of taking reserpine, the occurrence of hypertension is possible:
Ascorbic acid increases the concentration of benzylpenicillin and tetracyclines in the blood; reduces the therapeutic effect of antipsychotics (neuroleptics) - phenothiazine derivatives, tubular reabsorption of amphetamine and tricyclic antidepressants. Ascorbic acid reduces the effectiveness of heparin and indirect anticoagulants. Acetylsalicylic acid reduces absorption of ascorbic acid.