Veterinary and human toxicology
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A 59-y-old with a history of chronic renal failure on hemodialysis was diagnosed with herpes zoster and begun on 800 mg acyclovir 5 times daily. Two days later the patient developed visual hallucinations, ataxia, confusion and memory loss along with focal myoclonus, nausea and vomiting. No fever, elevated WBC count or significant electrolyte imbalance was found. ⋯ After a second course of hemodialysis the next day the patient's mental status improved, and she was discharged 5 d later. Due to its low volume of distribution (0.6 L/kg), low protein binding (about 15%) and water solubility, acyclovir is an example of the ideal drug that can be removed by hemodialysis. About 45% of the total body amount can be extracted through a 3-h course of hemodialysis with resultant improvement in symptoms.
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Comparative Study
Effects of cadmium and verapamil on ketamine-induced anesthesia in mice.
Previous studies have shown that pretreatment with cadmium and verapamil potentiated the effects of some CNS active drugs. The objective of this study was to determine the influence of these agents on ketamine anesthesia in adult male mice. Intraperitoneal administration of 300 mg ketamine/kg produced sleeping time of 40.88 +/- 2.98 min. ⋯ Pretreatment with 3 mg cadmium/kg sc before 1 w caused a reduction in the potentiating effects of a 2nd dose of cadmium in ketamine-induced anesthesia in mice. These results indicate that prolongation of ketamine-induced anesthesia by cadmium and verapamil could be mediated either by inhibition of hepatic P450 metabolizing enzymes or neuronal calcium channels blockade. The tolerance to the potentiating effects of cadmium could be mediated by hepatic metallothionein induction and a reduction in total body cadmium burden.
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Alkane arsenate herbicides are available commercially, and their acute toxicity has been well documented in previous studies. Animal studies have indicated that dimercaptosuccinic acid (DMSA) can be used as an oral chelating agent. A 20-y-old white male cocaine addict attempted suicide by drinking approximately 500 ml of a 16% monosodium methanearsenate solution. ⋯ However liver functions were abnormal, with elevation of serum transaminases, which later proved secondary to chronic hepatitis. No side effects of DMSA was encountered during the therapy. DMSA was successfully used to detoxify acute organoarsenate poisoning in a clinical setting, supporting experimental reports in the literature.