Dicyclomine (Dicyclomine Hydrochloride) - Drug Interactions, Contraindications, Overdosage

DRUG INTERACTIONS

Carcinogenesis, Mutagenesis, Impairment of Fertility

There are no known human data on long-term potential for carcinogenicity or mutagenicity.

Long-term studies in animals to determine carcinogenic potential are not known to have been conducted.

In studies in rats at doses of up to 100 mg/kg/day, dicyclomine hydrochloride produced no deleterious effects on breeding, conception, or parturition.

Pregnancy

Teratogenic Effects

Pregnancy Category B

Reproduction studies have been performed in rats and rabbits at doses up to 33 times the maximum recommended human dose based on 160 mg/day (3 mg/kg) and have revealed no evidence of impaired fertility or harm to the fetus due to dicyclomine. Epidemiologic studies in pregnant women with products containing dicyclomine hydrochloride (at doses up to 40 mg/day) have not shown that dicyclomine increases the risk of fetal abnormalities if administered during the first trimester of pregnancy. There are, however, no adequate and well-controlled studies in pregnant women at the recommended doses (80 to 160 mg/day). Because animal reproduction studies are not always predictive of human response, dicyclomine hydrochloride as indicated for functional bowel/irritable bowel syndrome should be used during pregnancy only if clearly needed.

OVERDOSAGE

Signs and Symptoms

The signs and symptoms of overdosage are headache; nausea; vomiting; blurred vision; dilated pupils; hot, dry skin; dizziness; dryness of the mouth; difficulty in swallowing; and CNS stimulation. A curare-like action may occur (i.e., neuromuscular blockade leading to muscular weakness and possible paralysis).

A 37-year old female reported numbness on the left side, cold fingertips, blurred vision, abdominal and flank pain, decreased appetite, dry mouth, and nervousness following ingestion of 320 mg daily (four 20 mg tablets QID) for four days. These events resolved after discontinuing the dicyclomine.

Oral LD₅₀

The acute oral LD₅₀ of the drug is 625 mg/kg in mice.

Minimum Human Lethal Dose/Maximum Human Dose Recorded

The amount of drug in a single dose that is ordinarily associated with symptoms of overdosage or that is likely to be life-threatening, has not been defined. The maximum human oral dose recorded was 600 mg by mouth in a 10-month-old child and approximately 1500 mg in an adult, each of whom survived.

In three of the infants who died following administration of dicyclomine hydrochloride (see WARNINGS), the blood concentrations of drug were 200, 220, and 505 ng/mL, respectively.

Dialysis

It is not known if dicyclomine hydrochloride is dialyzable.

Treatment

Treatment should consist of gastric lavage, emetics, and activated charcoal. Sedatives (e.g., short-acting barbiturates, benzodiazepines) may be used for management of overt signs of excitement. If indicated, an appropriate parenteral cholinergic agent may be used as an antidote.

CONTRAINDICATIONS

1. Obstructive uropathy.
2. Obstructive disease of the gastrointestinal tract.
3. Severe ulcerative colitis. (See PRECAUTIONS.)
Reflux esophagitis.
4. Unstable cardiovascular status in acute hemorrhage.
5. Glaucoma.
6. Myasthenia gravis.
7. Evidence of prior hypersensitivity to dicyclomine hydrochloride or other ingredients of these formulations.
8. Infants less than 6 months of age. (See WARNINGS and PRECAUTIONS: Information for Patients.)
9. Nursing mothers. (See WARNINGS and PRECAUTIONS: Information for Patients.)