Dextropropoxyphene Alprazolam

Inhibition of alprazolam metabolism by dextropropoxyphene has been reported (37). 

Extracted acenocoumarol, acepromazine, aceprometazine, acetaminophen, aconitine, ajmaline, albuterol, alimemazine, alminoprofen, alpidem, alprazolam, alprenolol, amisul-pride, amitriptyline, amodiaquine, amoxapine, aspirin, astemizole, atenolol, benazepril, benperidol, benzocaine, benzoylecgonine, bepridil, betaxolol, bisoprolol, brompheniramine, bumadizone, bupivacaine, buprenorphine, buspirone, caffeine, carbinoxamine, carpip-ramine, carteolol, celiprolol, cetirizine, chlorambucil, chlordiazepoxide, chlormezanone, chlorophenacinone, chloroquine, chlorpheniramine, chlorpromazine, chlorpropamide, cibenzoline, cicletanine, clemastine, clobazam, clomipramine, clonazepam, clonidine, clorazepate, clozapine, cocaine, codeine, colchicine, cyamemazine, cyclizine, cycloguanil, cyproheptadine, cytarabine, dacarbazine, daunorubicin, debrisoquine, demexiptiline, de-sipramine, dextromethorphan, dextromoramide, dextropropoxyphene, diazepam, diazox-... 

Another study in healthy subjects found that dextropropoxyphene 65 mg every 6 hours prolonged the alprazolam half-life from 11.6 to 18.3 hours, and decreased the clearance from 1.3 to 0.8 mL/minute per kg. The pharmacokinetics of single doses of diazepam and lorazepam were not significantly affected. It would seem that dextropropoxyphene inhibits the metabolism (hydroxylation) of the alprazolam by the liver, thereby reducing its loss from the body, but has little or no effect on the A/-demethylation or glucuronidation of the other two benzodiazepines. The clinical importance of this is uncertain, but the inference to be drawn is that the CNS depressant effects of alprazolam will be increased, over and above the simple additive CNS depressant effects likely when other benzodiazepines and dextropropoxyphene are taken together. More study is needed. 

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