Methacholine

Risk Summary

The available data from published literature on methacholine use in pregnant women are insufficient to evaluate for a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. Animal reproduction studies evaluating effects of methacholine chloride on embryofetal development have not been conducted. Diagnosis of bronchial airway hyperreactivity with bronchoprovocation challenge is not recommended for pregnant women because of the potential for hypoxia in the fetus. If bronchial airway hyperreactivity is suspected, consider trial of empiric treatment.

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the United States general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.

Risk Summary

There are no available data on the presence of methacholine chloride in human milk, the effect on the breastfed infant, or the effect on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for methacholine and any potential adverse effects on the breastfed infant from methacholine or from the underlying maternal condition.

There have been no studies with methacholine chloride that would permit an evaluation of its carcinogenic or mutagenic potential or of its effect on fertility.

The following adverse reactions associated with the use of methacholine were identified in clinical studies or post marketing reports. Because some of these reactions were reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Bronchospasm (includes symptoms such as chest tightness, cough or wheezing).

Adverse reactions less commonly associated with methacholine include headache, throat irritation, light-headedness and itching.