Basic & clinical pharmacology & toxicology
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Basic Clin. Pharmacol. Toxicol. · Mar 2012
ReviewPharmacokinetic-pharmacodynamic modelling of opioids in healthy human volunteers. a minireview.
Pain is characterized by its multi-dimensional nature, explaining in part why the pharmacokinetic/pharmacodynamic (PK/PD) relationships are not straightforward for analgesics. The first part of this MiniReview gives an overview of PK, PD and PK/PD models, as well as of population approach used in analgesic studies. The second part updates the state-of-the-art in the PK/PD relationship of opioids, focusing on data obtained on experimental human pain models, a useful tool to characterize the PD of analgesics. ⋯ The studies assessing the PK/PD of fentanyl and its derivatives showed a short t(1/2) k(e0) for analgesia, between 0.2 and 9 min., reflecting a short onset of effect. In conclusion, depending on the speed of transfer between the plasma and the effect site as well as the participation of active metabolites, the time-course of the analgesic effects can be close to the plasma concentrations (alfentanil and derivates) or observed with a prolonged delay (codeine, buprenorphine, morphine). These PK/PD data can be used to better characterize the differences between opioids, and partly explain the important observed variability among opioids in experimental conditions and should be systematically evaluated during drug development to better predict their selection in specific clinical conditions.
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Basic Clin. Pharmacol. Toxicol. · Mar 2012
Lithium attenuates peripheral neuropathy induced by paclitaxel in rats.
As a cancer chemotherapeutic agent, paclitaxel (Taxol® ) causes dose-related peripheral neuropathy in human beings. The mechanisms underlying this toxicity are currently unknown, and there are no validated treatments for its prevention or control. To assess whether lithium as a pre-treatment and at subtherapeutic dose could prevent the peripheral neuropathy produced by it, rats were treated with paclitaxel (2 mg/kg i.p. every other day for a total of 16 times) and/or lithium chloride (300 mg/l) via water supply. ⋯ The same results were observed in histopathological examinations; however, dorsal root ganglion neurons did not significantly change in the paclitaxel-treated groups. These results suggest that lithium, at subtherapeutic doses, can prevent both motor and sensory components of paclitaxel neuropathy in rats. Thus, lithium at these doses, as an inexpensive and relatively safe salt, may be useful clinically in preventing the neuropathy induced by paclitaxel treatment.