Brands, Medical Use, Clinical Data
Drug Category
- Adjuvants, Anesthesia
- Analgesics, Opioid
- Narcotic Antagonists
- Narcotics
Dosage Forms
Brands / Synonyms
Fortalgesic; Fortalin; Fortral; L-pentazocine; Liticon; Pentagin; Pentazocaine; Pentazocin; Pentazocine and Acetaminophen; Pentazocine and Naloxone; Pentazocine {D.D.}; Soseton; Sosigon; Talacen; Talwan; Talwin; Talwin 50
Indications
For the relief of moderate to severe pain
Pharmacology
Pentazocine is an opiate antagonist and prevents or reverses the effects of opioids including respiratory depression, sedation and hypotension. Also, it can reverse the psychotomimetic and dysphoric effects of agonist-antagonists such as pentazocine. Pentazocine is an essentially pure narcotic antagonist, i.e., it does not possess the "agonistic" or morphine-like properties characteristic of other narcotic antagonists; Pentazocine does not produce respiratory depression, psychotomimetic effects or pupillary constriction. In the absence of narcotics or agonistic effects of other narcotic antagonists, it exhibits essentially no pharmacologic activity.
Mechanism of Action
Pentazocine is a potent analgesic which when administered orally in a 50 mg dose appears equivalent in analgesic effect to 60 mg (1 grain) of codeine. Onset of significant analgesia usually occurs between 15 and 30 minutes after oral administration, and duration of action is usually three hours or longer. Onset and duration of action and the degree of pain relief are related both to dose and the severity of pretreatment pain. Pentazocine weakly antagonizes the analgesic effects of morphine and meperidine; in addition, it produces incomplete reversal of cardiovascular, respiratory, and behavioral depression induced by morphine and meperidine. Pentazocine has about 1/50 the antagonistic activity of nalorphine. It also has sedative activity. The preponderance of evidence suggests that Pentazocine antagonizes the opioid effects by competing for the same receptor sites, especially the opioid mu receptor.
Absorption
Well absorbed from the gastro-intestinal tract
Toxicity
Not Available
Biotrnasformation / Drug Metabolism
Hepatic
Contraindications
TALWIN Nx should not be administered to patients who are hypersensitive to either pentazocine or naloxone.
Drug Interactions
Usage with Alcohol: Due to the potential for increased CNS depressants effects, alcohol should be
used with caution in patients who are currently receiving pentazocine.
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