Reproduction and teratology studies on propoxyphene napsylate

Methodological proposal in behavioural teratogenicity testing: assessment of propoxyphene, chlorpromazine, and vitamin A as positive controls

Pregnant Sprague-Dawley rats received either 80 mg/kg d-propoxyphene HCl or 20 mg/kg chlorpromazine HCl or 80,000 and 160,000 IU/kg vitamin A palmitate daily between the 6th and 20th days of gestation. Vehicle control groups were similarly treated with saline or corn oil and considered as negative controls. Offspring were examined for physical landmarks, neuromotor development, and behaviour using righting reflex, swimming, negative geotaxis, open field, rotarod, water maze, and nocturnal activity. This test battery included biochemical measurements. No reduction in parental weight and physical offspring development was observed. All these treatments produced long-term changes in more than one test. Vitamin A palmitate (160,000 IU/kg) was judged as the best positive control with this test battery for future investigation of the behavioural teratology of drugs.

Propoxyphene and acetaminophen. Possible effects on the fetus

Propoxyphene (Darvon) and acetaminophen (Tylenol) are widely prescribed analgesic agents. Both can cross the placenta, and propoxyphene can produce serious withdrawal symptoms in newborns. Neither propoxyphene nor acetaminophen is considered a teratogen, yet, three malformed infants who were antenatally exposed to propoxyphene have previously been reported. We report a fourth case of an infant, with withdrawal symptoms and cranial-facial and digital malformations, born to a women who used propoxyphene and acetaminophen throughout her pregnancy. We suggest that possibility that the antepartum use of propoxyphene and acetaminophen, in combination, may be teratogenic.

Psychotropic drugs as behavioral teratogens

Three psychotropic drugs were administered to pregnant rats and were then evaluated for their behavioral and reproductive effects in the offspring. Control rats received either saline or vitamin A. Prochlorperazine had the most disruptive effects on reproduction and growth, but had the least effect on behavior. Propoxyphene had no apparent effects on reproduction or growth, but produced a variety of behavioral changes. Fenfluramine was intermediate in its effects on reproduction and growth and had behavioral effects that were revealed in tests of preweaning development. The data suggest that systematic tests of behavior add important information to evaluations of reproductive toxicity that cannot, at present, be obtained by other means.