PENTAZOCINE-NALOXONE HCL (pentazocine hcl/naloxone hcl)


Drug overview for PENTAZOCINE-NALOXONE HCL (pentazocine hcl/naloxone hcl):

Generic name: PENTAZOCINE HCL/NALOXONE HCL (pen-TAZZ-oh-seen/nal-OX-own)
Drug class: Opioid Antagonists
Therapeutic class: Analgesic, Anti-inflammatory or Antipyretic

Naloxone hydrochloride is an opioid antagonist. Pentazocine is a synthetic opiate partial agonist analgesic.

Pentazocine is used as an analgesic for relief of moderate to severe pain. The drug has been used in the management of postoperative pain, including that associated with dental surgery, orthopedic pain, pain associated with cancer, and renal or biliary colic. Pentazocine also has been used parenterally (pentazocine lactate injection is no longer commercially available in the US) to provide preoperative sedation and analgesia, as an adjunct to surgical anesthesia, and for obstetrical analgesia during labor.

Although there have been many clinical studies comparing the analgesic effect of pentazocine with other analgesics, it is difficult to assess the relative efficacy of the drugs because of varying methodology and premedications used in these studies. Clear differences in analgesic efficacy between pentazocine and other opiate partial agonist analgesics such as butorphanol or nalbuphine have not been demonstrated. In general, usual parenteral doses of pentazocine are as effective in relieving moderate to severe pain as usual parenteral doses of morphine, meperidine, butorphanol, or nalbuphine.

The duration of analgesia of IM pentazocine appears to be shorter than that of IM morphine. The analgesic activity of 50 mg of oral pentazocine is about equal to that of 60 mg of oral codeine or 600 mg or oral aspirin. Pentazocine hydrochloride and aspirin in combination for oral administration results in additive analgesic effects.

The oral dosage form of pentazocine was reformulated in the 1980s to contain a small amount of the opiate antagonist, naloxone hydrochloride. The reformulation, pentazocine and naloxone hydrochlorides tablets, potentially eliminates the misuse of the oral preparation in combination with the antihistamine, tripelennamine (no longer commercially available in the US); the combination, known as T's and blues, has been misused via parenteral injection by opiate addicts and drug abusers since its effect was purported to be similar to IV diacetylmorphine (heroin). Since naloxone is inactive when administered orally in the amount (0.5 mg) present in this formulation, its presence does not affect the efficacy of pentazocine when the tablets are administered orally; however, if the tablets are ground up and solubilized for parenteral administration, the naloxone will antagonize the effects of pentazocine and will precipitate withdrawal symptoms in drug abusers who are dependent on opiates.

The reformulated preparation is still subject to misuse and abuse by the oral route. Because it does not suppress the abstinence syndrome and may induce withdrawal in opiate-dependent patients, pentazocine cannot be substituted for opiates after physical dependence has been established without prior detoxification. For further information on the role of opiate analgesics in the management of acute or chronic pain, see Uses: Pain, in the Opiate Agonists General Statement 28:08.08.
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The following indications for PENTAZOCINE-NALOXONE HCL (pentazocine hcl/naloxone hcl) have been approved by the FDA:

Indications:
Pain


Professional Synonyms:
None.