Gastroenteritis causing failure of oral contraception.

Abstract

Neurological adverse effects are known to complicate vincristine treatment. In occasional reports of bowel and bladder disturbance it has not been possible to incriminate autonomic neuropathy. We report here three patients with symptoms and signs which could be ascribed to vincristine-induced autonomic neuropathy. CommentNeurotoxicity is a well recognized adverse effect of vincristine treatment. The predominant change is an axonal neuropathy,l which usually takes the form of peripheral neuropathy, though central nervous system abnormalities have been described. Constipation commonly occurs and bladder disturbance has been reported,2 and it has been suggested that these features (which usually post-date peripheral neuropathy) are a result of autonomic nerve damage.3In primary autonomic degeneration4 sphincter disturbance usually precedes other neurological symptoms-for example, postural hypotension, abnormal Valsalva response, defective sweating, episodic altered consciousness, and myoclonic jerks. Two patients (cases 1 and 2) showed no evidence of sphincter disturbance, though there was profound postural hypotension and abnormal Valsalva responses. Both patients also developed peripheral neuropathy. In case 3 bladder and bowel atony were pronounced, and postural hypotension, myoclonic jerks, and severe symptomatic peripheral neuropathy were observed.Postural hypotension is common in the elderly,5 and this, together with the onset of illness and relative immobility, might have contributed to the findings in cases 1 and 2. Vincristine toxicity is worse with increasing dosage and frequency of administration, but elderly patients are also more sensitive to the toxic effects of all cytotoxic drugs, and the doses of such agents may have to be modified accordingly. Certainly our two older patients (cases 1 and 2) had each received only 5 mg vincristine in two doses given a week apart. The third patient (aged 56) received six 2-mg doses of vincristine over three months.All symptoms improved three to four weeks after stopping vincristine, but despite some improvement postural hypotension and peripheral neuropathy persisted. In each patient treatment was changed to vinblastine without deterioration in neurological status.In the light of our findings regular estimation of blood pressure for exaggerated postural fall may give early warning of vincristine neurotoxicity.

Multicenter study in Hungary with a 30μg ethinylestradiol- and 150μg desogestrel-containing monophasic oral contraceptive

“…Conditions known to impair contraceptive reliability include diarrhea [17] and vomiting [18]. During this study, diarrhea was experienced in 84 (3.3%) of the cycles, and vomiting in 55 (2.1%).…”

Factors Contributing to Variability in Drug Pharmacokinetics. I. Absorption

“…Absorption of ampicillin and nalidixic acid is reduced in infants and children with acute shigellosis and the extent of reduction is related to the severity of the condition (46). Failure of oral contraception in women suffering from gastroenteritis associated with diarrhoea, or diarrhoea and vomiting, has already been described (14).…”