CAUSES DECREASED EFFICACY OF OTHER DRUGS LIKE ORAL ANTICOAGULANTS, ORAL CONTRACEPTIVES, PHENYTOIN.VIT B6 REDUCES ITS SERUM CONC.
ANALGESICS - DEXTROPROPOXYPHENE MAY INCREASE PLASMA BUTOBARBITONE LEVELS BY 8-25%. METHADONE PLASMA LEVELS WERE REDUCED. PETHIDINE HAS ADDITIVE SEDATIVE ACTION.
ANTIARRHYTHMICS :- DISOPYRAMIDE , QUINIDINE & LIGNOCAIN CLEARENCE IS INCREASED.
ANTIBACTERIALS :- CHLORAMPHENICOL INCREASE PLASMA CLEARANCE OF PHENOBARBITOBE & VICE VERSA. BUTOBARBITONE INCREASES DOXYCYCLINE METABOLISM.
ANTIDEPRESSANTS :- MAOIS MAY PROLONG THE CNS DEPRESSANT EFFECTS OF SOME BARBITURATES, PROBABLY BY INHIBITION OF THEIR METABOLISM. HOWEVER, MAOIS LIKE OTHER ANTIDEPRESSANTS MAY ANTAGONISE THE ANTIEPILEPTIC ACTIVITY OF BUTOBARBITONE & OTHER ANTIEPILEPTICS BY LOWERING THE CONVULSIVE THRESHOLD.
HYPERICUM INCREASES BUTOBARBITONE METABOLISM ALSO.
ANTIEPILEPTICS :- SOD VALPROATE INCREASES BUTOBARBITONE PLASMA CONC. BY 17-48%, WHILE BUTOBARBITONE REDUCES VALPROATE SERUM CONC BY INCREASING ITS METABOLISM.
PHENYTOIN IN SOME PTS CAUSE RISE IN PLASMA CONC OF BUTOBARBITONE. BUTOBARBITONE WHILE REDUCES SERUM PHENYTOIN CONC BY INDUCING ITS METABOLISM BUT IN BOTH CASES NO DOSE CHANGE IS REQUIRED.
ANTIFUNGALS :- GRISEOFULVIN ORAL ABSORPTION IS REDUCED WHILE ITRACONAZOLE METABOLISM IS INDUCED CAUSING LOWER PLASMA LEVELS.
ANTIPPROTOZOALS :- METRONIDAZOLE METABOLISM IN ENHANCED.
ANTIPSYCHOTICS :- AS WITH ALL ANTIEPILEPTICS, ANTIPSYCHOTICS MAY ANTAGONISE ANTIEPILEPTIC ACTIVITY OF BUTOBARBITONE BY LOWERING THE CONVULSIVE THRESHOLD.
ANTIVIRALS :- HIV PROTEASE INHIBITORS SERUM LEVEL IS REDUCED DUE TO ENHANCED METABOLISM.
BETABLOCKERS :- PLASMA CONC IS REDUCED DUE TO INCREASED METABOLISM.
CALCIUM CHANNEL BLOCKERS :- BOTH NIFEDIPINE & VERAPAMIL PLASMA LEVELS ARE REDUCED DUE TO INCREASED METABOLISM.
CARDIAC GLYCOSIDES :- DIGOXIN LEVELS ARE GREATLY REDUCED DUE TO INCREASED METABOLISM.
CYCLOSPORIN : PLASMA LEVELS ARE REDUCED
CORTICOSTEROIDS :- PLASMA LEVELS ARE REDUCED DUE TO INCREASED METABOLISM
DIURETICS - FRUSEMIDE INCREASED SERUM BUTOBARBITONE LEVELS
THYROID HORMONE :- PLASMA CONC IS REDUCED
VACCINE :- INFLUENZA VACCINE CAN CAUSE PROLONGES RISE IN PLASMA LEVELS IN SOME PTS.