Analgesic abuse: maximal tolerated daily doses of acetylsalicylic acid

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The influence of sex and age in albino rats given a daily oral dose of caffeine at a high dose level

Caffeine was given daily for 14 days in an oral dose of 185 mg/kg to male and female albino rats in groups of increasing body weight. The sensitivity of rats to the lethal effects of caffeine increased with increase in age. Psychotoxic (auto-mutilation plus hemorrhage) deaths were most common in young rats, and hypokinetic–convulsive deaths in older animals. In survivors, the incidence of glycosuria and hydration of the kidneys was greater, and dehydration of the adrenal glands and gonads less, in older than in younger rats. Sublethal signs of toxicity in male survivors were greater than in female survivors. Anorexia and loss of body weight were greater in male than in female survivors, diuresis was less evident, loss of muscle weight was greater, and the relative gain in weight of the adrenal glands and gastrointestinal tract were greater. In brief, caffeine was found to be more toxic in older than in younger rata and in males than in females.