CAUSES DECREASED EFFICACY OF OTHER DRUGS LIKE ORAL ANTICOAGULANTS, ORAL CONTRACEPTIVES, PHENYTOIN.VIT B6 REDUCES ITS SERUM CONC.
ANALGESICS - DEXTROPROPOXYPHENE MAY INCREASE PLASMA BUTALBITAL 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. BUTALBITAL INCREASES DOXYCYCLINE METABOLISM.
ANTIDEPRESSANTS :- ANTIDEPRESSANTS MAY ANTAGONISE THE ANTIEPILEPTIC ACTIVITY OF BUTALBITAL & OTHER ANTIEPILEPTICS BY LOWERING THE CONVULSIVE THRESHOLD.
HYPERICUM INCREASES BUTALBITAL METABOLISM ALSO.
ANTIEPILEPTICS :- SOD VALPROATE INCREASES BUTALBITAL PLASMA CONC. BY 17-48%, WHILE BUTALBITAL REDUCES VALPROATE SERUM CONC BY INCREASING ITS METABOLISM.
PHENYTOIN IN SOME PTS CAUSE RISE IN PLASMA CONC OF BUTALBITAL. BUTALBITAL 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 BUTALBITAL 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 BUTALBITAL LEVELS
THYROID HORMONE :- PLASMA CONC IS REDUCED
VACCINE :- INFLUENZA VACCINE CAN CAUSE PROLONGES RISE IN PLASMA LEVELS IN SOME PTS.