PILOCARPINE

Fetal Risk Summary

Pilocarpine is used topically in the eye for glaucoma or as oral tablets in the treatment of dry mouth. In reproduction studies in rats at a dose about 26 times the maximum human oral dose based on body surface area (MRHD), adverse effects consisting of a decrease in fetal weight and an increase in the incidence of skeletal variations were observed (1). These effects may have been secondary to maternal toxicity (1). In another study with rats, doses approximately 10 times the MRHD during gestation and lactation were associated with an increased incidence of stillbirths, whereas doses 5 or more times the MRHD were associated with decreased neonatal survival and reduced pup body weights (1).

A single report of the topical use during pregnancy has been located. A woman with glaucoma was treated throughout gestation with topical pilocarpine, two drops twice daily, timolol, two drops each eye, and oral acetazolamide (2). Within 48 hours of delivery at 36 weeks' gestation, the infant presented with hyperbilirubinemia, hypocalcemia, hypomagnesemia, and metabolic acidosis. The toxic effects, attributed to the carbonic anhydrase inhibitor acetazolamide (see Acetazolamide), resolved quickly on treatment. Mild hypertonicity requiring physiotherapy was observed at examinations at 1, 3, and 8 months of age.

Breast Feeding Summary

No reports describing the use of pilocarpine during lactation have been located. Because of the relatively low molecular weight (about 245 for the hydrochloride salt), excretion into breast milk should be expected.

References

1. Product information. Salagen. MGI Pharma, 2000.
2. Merlob P, Litwin A, Mor N. Possible association between acetazolamide administration during pregnancy and metabolic disorders in the newborn. Eur J Obstet Gynecol Reprod Biol 1990;35:85–8.