Propoxyphene dosing

Propoxyphene products in excessive doses, either alone or in combination with other CNS depressants (including alcohol), are a major cause of drug-related deaths. Fatalities within the first hour of overdosage are not uncommon. In a survey... 

Elderly- Propoxyphene metabolism rate may be reduced in some patients. Consider increased dosing interval. 

Propoxyphene interacts with several drugs. The use of sedatives in combination with propoxyphene can be fatal. In addition, the metabolism of the drug is increased in smokers due to induction of liver enzymes. Thus, smokers may require a higher dose of the drug for pain relief. Propoxyphene enhances the effects of both warfarin and carbamazepine and may increase the toxicity associated with both drugs, such as bleeding and sedation, respectively. 

Cimetidine, propoxyphene, and isoniazid also have been reported to inhibit metabolism of carbamazepine. It is essential to monitor blood levels and adjust the dose if necessary whenever additional drugs are given to patients taking carbamazepine. 

Propoxyphene is chemically related to methadone but has low analgesic activity. Various studies have reported its potency at levels ranging from no better than placebo to half as potent as codeine that is, 120 mg propoxyphene = 60 mg codeine. Its true potency probably lies somewhere between these extremes, and its analgesic effect is additive to that of an optimal dose of aspirin or acetaminophen. However, its low efficacy makes it unsuitable, even in combination with aspirin, for severe pain. The increasing incidence of deaths associated with its use and misuse has caused it to be scheduled as a controlled substance. Moreover, banning its use in the United States is under consideration. 

Naloxone Narcotic drugs, other opioid derivatives A specific antagonist of opioids 1-2 mg initially by IV, IM, or subcutaneous injection. Larger doses may be needed to reverse the effects of overdose with propoxyphene, codeine, or fentanyl derivatives. Duration of action (2-3 hours) may be significantly shorter than that of the opioid being antagonized. 

Inturrisi, C.E., Colburn, W.A., Verebey, K., Dayton, H.E., Woody, G.E., O Brien, C.P. Propoxyphene and norpropoxyphene kinetics after single and repeated doses of propoxyphene, Clin. Pharmacol. Ther. 1982, 31, 157-167. 

Lopinavir/Ritonavir (Kaletra) [Anrirelroviral/Protease Inhibitor] Uses HIV Infxn Action Protease inhibitor Dose Adults. Tx naive 2 tab PO daily or 1 tab PO bid Tx experiencedpt 1 tab PO bid (T dose if w/ amprenavir, efavirenz, fosamprenavir, nelfinavir, nevirapine) Peds. 7-15 kg 12/3 mg/kg PO bid 15-40 kg 10/2.5 mg/kg PO bid >40 kg Adult dose w/ food Caution [C, /-] Numerous interactions Contra w/drugs dependent on CYP3A/CYP2D6 (Table VI-8) Disp Tab, soln SE Avoid disulfiram (soln has EtOH), metronidazole GI upset, asthenia, T cholesterol/triglycerides, pancreatitis protease metabolic synd Interactions T Effects Wl clarithromycin, erythromycin T effects OF amiodarone, amprenavir, azole andfungals, bepridil, cisapride, cyclosporine, CCBs, ergot alkaloids, flecainide, flurazepam, HMG-CoA reductase inhibitors, indinavir, lidocaine, meperidine, midazolam, pimozide, propafenone, propoxyphene, quinidine, rifabutin, saquinavir, sildenafil, tacrolimus, terfenadine, triazolam, zolpidem 1 effects Wl barbiturates, carbamazepine, dexamethasone, didanosine, efavirenz, nevirapine, phenytoin, rifabutin, rifampin, St. John s wort 1 effects OF OCPs, warfarin EMS Use andarrhythmics and benzodiazepines... 

T effects OF amiodarone, astemizole, atorvastadn, barbiturates, bepridil, bupropion, cerivastatin, cisapride, clorazepate, clozapine, clarithromycin, desipramine, diazepam, encainide, ergot alkaloids, estazolam, flecainide, flurazepam, indinavir, ketoconazole, lovastatin, meperidine, midazolam, nelfinavir, phenytoin, pimozide, piroxicam, propafenone, propoxyphene, quinidine, rifabutin, saquinavir, sildenafil, simvastatin, SSRIs, TCAs, terfenadine, triazolam, troleandomycin, zolpidem X effects W/ barbiturates, carbamazepine, phenytoin, rifabutin, rifampin, St. John s wort, tobacco X effects OF didanosine, hypnotics, methadone, OCPs, sedatives, theophylline, warfarin EMS T Effects of amiodarone, diazepam, midazolam and BBs, may need X- doses concurrent use of Viagra-type drugs can lead to hypotension X- effects of warfarin concurrent EtOH use can T adverse effects T glucose ODs May cause an extension of adverse SEs symptomatic and supportive Rivasrigmine (Exelon) [Cholinesterase Inhibitor/Anri ... 

Some compounds that affect respiratory rate. Acetaminophen is one of the simple analgesics, which in therapeutic doses relieves pain without any effect on an individual s consciousness. Propoxyphene hydrochloride is a narcotic analgesic, a class of substances that can cause biochemical changes in the body leading to chemical dependency. 

SCHEDULE II Certain barbiturates, cocaine, codeine, codeine + acetaminophen (depends on dose and formulation), fentanyl (depends on dose), hydrocodone, hydromorphone, meperidine, methadone, morphine (depends on combination with other pain relievers), oxycodone, propoxyphene... 

Amphetamines contribute to excessive CNS stimulation if used with large doses of propoxyphene... 

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