Drugs in Pregnancy and Lactation: Tenth Edition

TERPIN HYDRATE

Respiratory Drug (Expectorant)

PREGNANCY RECOMMENDATION: Contraindicated (Significant Alcohol Content)

BREASTFEEDING RECOMMENDATION: Contraindicated (Significant Alcohol Content)

PREGNANCY SUMMARY

Terpin hydrate is available as a liquid preparation that contains a significant amount (about 42%) of ethanol. It should not be used in pregnancy.

FETAL RISK SUMMARY

Although no longer approved as an expectorant, this agent has been used for a number of years and may still be available for this indication. At one time it was combined with codeine as an expectorant–antitussive proprietary mixture. No animal reproductive studies of terpin hydrate have been located.

The Collaborative Perinatal Project monitored 50,282 mother–child pairs, 146 of whom had 1st trimester exposure to terpin hydrate (1, pp. 378–89). Congenital malformations were observed in 13 (standardized relative risk [SRR] 1.29) of the newborns. For use anytime in pregnancy, 1762 mother–child pairs were exposed (1, p. 442). Twenty-nine (30.6 expected) of the newborns had anomalies (SRR 0.95). Neither of the exposure periods indicates an increased fetal risk from the drug. Specific malformations or conditions identified following use of terpin hydrate anytime in pregnancy were any benign tumors 9 (SRR 1.9), clubfoot 11 (SRR 1.2), and inguinal hernia 34 (SRR 1.4) (1, p. 496). However, these data are uninterruptible without independent confirmation from other studies. Any positive or negative associations may have occurred by chance (1, p. 481). A 1964 study found no abnormalities in six infants exposed in utero to terpin hydrate (with or without codeine) during the 1st trimester (2). Neither of the above studies specified the doses consumed by the patients.

The recommended dose of terpin hydrate, which contains approximately 42% ethanol, is 5–10 mL 3–4 times daily. The maximum daily dose would therefore contain about 17 mL of absolute ethanol or about one-half of the amount that has been shown to produce mild fetal alcohol syndrome (see Ethanol). Because the minimum amount of ethanol exposure required to produce fetal developmental toxicity is unknown, this product should be avoided during pregnancy.

BREASTFEEDING SUMMARY

No reports describing the use of terpin hydrate during lactation have been located. Because of the high ethanol content (about 42%) of terpin hydrate, frequent use of this product should be avoided during lactation (see also Ethanol).

References

1.Heinonen OP, Slone D, Shapiro S. Birth Defects and Drugs in Pregnancy. Littleton, MA: Publishing Sciences Group, 1977.

2.Mellin GW. Drugs in the first trimester of pregnancy and the fetal life of Homo sapiens. Am J Obstet Gynecol 1964;90:1169–80.