PRECAUTIONS General Since a subtherapeutic dose of atropine has been added to the diphenoxylate hydrochloride, consideration should be given to the precautions relating to the use of atropine. In children, diphenoxylate hydrochloride and atropine sulfate should be used with caution since signs of atropinism may occur even with recommended doses, particularly in patients with Down’s syndrome. Information for Patients INFORM THE PATIENT (PARENT OR GUARDIAN) NOT TO EXCEED THE RECOMMENDED DOSAGE AND TO KEEP DIPHENOXYLATE HYDROCHLORIDE AND ATROPINE SULFATE OUT OF THE REACH OF CHILDREN AND IN A CHILD-RESISTANT CONTAINER. INFORM THE PATIENT OF THE CONSEQUENCES OF OVERDOSAGE, INCLUDING SEVERE RESPIRATORY DEPRESSION AND COMA, POSSIBLY LEADING TO PERMANENT BRAIN DAMAGE OR DEATH. Diphenoxylate hydrochloride and atropine sulfate may produce drowsiness or dizziness. The patient should be cautioned regarding activities requiring mental alertness, such as driving or operating dangerous machinery. Potentiation of the action of alcohol, barbiturates, and tranquilizers with concomitant use of diphenoxylate hydrochloride and atropine sulfate should be explained to the patient. The physician should also provide the patient with other information in this labeling, as appropriate. Drug Interactions Known drug interactions include barbiturates, tranquilizers, and alcohol. Diphenoxylate hydrochloride and atropine sulfate may interact with MAO inhibitors (see WARNINGS). In studies with male rats, diphenoxylate hydrochloride was found to inhibit the hepatic microsomal enzyme system at a dose of 2 mg/kg/day. Therefore, diphenoxylate has the potential to prolong the biological half-lives of drugs for which the rate of elimination is dependent on the microsomal drug metabolizing enzyme system. Carcinogenesis, Mutagenesis, Impairment of Fertility No long-term study in animals has been performed to evaluate carcinogenic potential. Diphenoxylate hydrochloride was administered to male and female rats in their diets to provide dose levels of 4 and 20 mg/kg/day throughout a three-litter reproduction study. At 50 times the human dose (20 mg/kg/day), female weight gain was reduced and there was a marked effect on fertility as only 4 of 27 females became pregnant in three test breedings. The relevance of this finding to usage of diphenoxylate hydrochloride and atropine sulfate in humans in unknown. Pregnancy Pregnancy Category C Diphenoxylate hydrochloride has been shown to have an effect on fertility in rats when given in doses 50 times the human dose (see above discussion). Other findings in this study include a decrease in maternal weight gain of 30% at 20 mg/kg/day and of 10% at 4 mg/kg/day. At 10 times the human dose (4 mg/kg/day), average litter size was slightly reduced. Teratology studies were conducted in rats, rabbits, and mice with diphenoxylate hydrochloride at oral doses of 0.4 to 20 mg/kg/day. Due to experimental design and small numbers of litters, embryotoxic, fetotoxic, or teratogenic effects cannot be adequately assessed. However, examination of the available fetuses did not reveal any indication of tetratogenicity. There are no adequate and well-controlled studies in pregnant women. Diphenoxylate hydrochloride and atropine sulfate should be used during pregnancy only if the anticipated benefit justifies the potential risk to the fetus. Nursing Mothers Caution should be exercised when diphenoxylate hydrochloride and atropine sulfate is administered to a nursing woman, since the physicochemical characteristics of the major metabolite, diphenoxylic acid, are such that it may be excreted in breast milk and since it is known that atropine is excreted in breast milk. Pediatric Use Diphenoxylate hydrochloride and atropine sulfate may be used as an adjunct to the treatment of diarrhea but should be accompanied by appropriate fluid and electrolyte therapy, if needed. DIPHENOXYLATE HYDROCHLORIDE AND ATROPINE SULFATE IS NOT RECOMMENDED FOR CHILDREN UNDER 2 YEARS OF AGE. Diphenoxylate hydrochloride and atropine sulfate should be used with special caution in young children because of the greater variability of response in this age group. See WARNINGS and DOSAGE AND ADMINISTRATION. In case of accidental ingestion by children, see OVERDOSAGE for recommended treatment.