With simultaneous use with drugs that depress the central nervous system (barbiturates, tranquilizers, anesthetics, narcotic analgesics, alcohol), it is possible to increase the depression of the central nervous system, respiratory depression.
Joint use with tricyclic antidepressants, MAO inhibitors, and maprotilin increases the risk of developing a malignant neuroleptic syndrome.
Perphenazine lowers the convulsive threshold, weakens the effect of anticonvulsants.
Simultaneous use with drugs for the treatment of hyperthyroidism increases the risk of agranulocytosis.
Application together with drugs that cause extrapyramidal reactions increases the severity of extrapyramidal disorders.
Joint use with antihypertensive drugs increases their hypotensive effect, can lead to orthostatic hypotension.
Perphenazine weakens the vasoconstrictor effect of ephedrine.
Application with adrenaline is contraindicated: perphenazine distorts the effect of adrenaline, leading to a drop in blood pressure.
Perphenazine reduces the antiparkinsonian effect of levodopa (due to blocking of dopamine receptors), inhibits the action of amphetamines, clonidine, guanetidine.
Perphenazine relieves the anticholinergic effect of other drugs, while its antipsychotic effect decreases.
Contraindicated use in conjunction with prochlorperazine because of the possible occurrence of a patient's long-term loss of consciousness.
Absorption of perphenazine is disrupted when used simultaneously with antacids, antiparkinsonian drugs, lithium preparations, so the use of these drugs should be separated by time intervals.
Simultaneous use of perphenazine and adsorbing antidiarrhoeals should be avoided.