Articles: opioid-analgesics.
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Eur. J. Clin. Pharmacol. · Jan 1980
Clinical pharmacokinetics and oral bioavailability of ketobemidone.
The basic pharmacokinetics and oral bioavailability of ketobenmidone have been studied in 6 patients after surgery. Plasma concentrations were first determined following intravenous administration of Ketogin 2 ml, containing ketobemidone chloride 10 mg and the spasmolytic N,N-dimethyl-3,3-diphenyl-1-methylallylamine chloride 50 mg, and then, on the second postoperative day, following oral administration of 2 tablets of Ketogin, each containing ketobemidone chloride 5 mg and the spasmolytic agent 25 mg. ⋯ The mean plasma half-life of elimination (t1/2 beta) was about the same following oral (2.45 +/- 0.73 h; SD, n = 5) as after intravenous administration (2.25 +/- 0.35 h; SD, n = 6). The low oral bioavailability and rapid elimination of ketobemidone demonstrated in this study suggest that the usual dosage recommendation for oral Ketogin (ketobemidone 5--10 mg every 6--7 h) in patients with severe pain is too low.
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There has long been a need for a potent, nonaddicting analgesic for the treatment of certain patients who have intractable pain that cannot be controlled by the more commonly used oral analgesics. Pentazocine was introduced on the market in I967 and has been reported to be a potent analgesic, comparable to meperidine and morphine but without their addicting properties. Consequently, this drug has been used on a long-term basis, and on many occasions the injections have been given by the patient or by nonprofessionals. ⋯ We have seen 14 patients with extensive cutaneous ulcerations, subcutaneous fibrosis, and multiple fistulous tracts due to the abuse of parenterally administered pentazocine. The tissue changes have a characteristic appearance and course, and it has been our experience that conservative treatment results in a poor response. We have had the best results with aggressive excision of the involved areas and coverage of the resultant defect with split-thickness skin graft.