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Drugs and Lactation Database (LactMed®) [Internet]. Bethesda (MD): National Institute of Child Health and Human Development; 2006-.

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Drugs and Lactation Database (LactMed®) [Internet].

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Last Revision: December 20, 2021.

Estimated reading time: 2 minutes

CASRN: 3930-20-9

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Drug Levels and Effects

Summary of Use during Lactation

Because of its extensive excretion into breastmilk, its renal excretion and minimal safety data in breastfed infants, other beta-adrenergic blocking drugs are preferred to sotalol, especially while nursing a newborn or preterm infant. Some authors recommend using sotalol during breastfeeding only while monitoring the infant closely for signs of beta-blockade.[1] Infants over 2 months of age have more mature kidney function and are less likely to be affected by sotalol in milk.

Drug Levels

The excretion of beta-adrenergic blocking drugs into breastmilk is largely determined by their protein binding. Those with low binding are more extensively excreted into breastmilk.[1,2]Accumulation of the drugs in the infant is related to the fraction excreted in urine. With 0% protein binding, 80 to 90% renal excretion and a moderately long half-life, sotalol presents a high risk for accumulation in infants, especially neonates. It is estimated that a fully breastfed infant would receive 22% of the maternal weight-adjusted dosage of sotalol.[3]

Maternal Levels. Twenty milk samples from 5 mothers at various times during the first 7 days postpartum while taking sotalol 200 to 600 mg daily orally had average sotalol milk levels of 10.5 mg/L (range 4.8 to 20.2 mg/L).[4]

One woman taking sotalol 80 mg three times daily on day 5 postpartum had sotalol milk levels of 4.1 and 3.7 mg/L at 6.3 and 7 hours after a dose, respectively. She was restudied at 105 days postpartum while taking 80 mg twice daily. Her milk sotalol levels were 2.4 and 3.2 mg/L at 2.8 and 3.3 hours after a dose, respectively.[1]

A mother taking oral sotalol 80 mg twice daily had milk sotalol levels of 5 and 4.4 mg/L at 3 hours after the dose on days 5 and 7 postpartum.[5]

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

A study of mothers taking beta-blockers during nursing found a numerically, but not statistically significant increased number of adverse reactions in those taking any beta-blocker. Although the ages of infants were matched to control infants, the ages of the affected infants were not stated. One of the mothers was taking sotalol.[6]

Bradycardia was not seen in one 12-day-old infant who was breastfed from birth during maternal use of 600 mg of sotalol daily.[4] In another breastfed infant whose mother was taking 80 mg 2 to 3 times daily for more than 3 months, no bradycardia was seen and developmental milestones were achieved normally.[1]

Beta-adrenergic blocking drugs with similar breastmilk excretion characteristics and renal elimination have caused adverse effects in breastfed newborns.[7,8]

Effects on Lactation and Breastmilk

Relevant published information on the effects of beta-blockade or sotalol during normal lactation was not found as of the revision date. A study in 6 patients with hyperprolactinemia and galactorrhea found no changes in serum prolactin levels following beta-adrenergic blockade with propranolol.[9]

Alternate Drugs to Consider

Propranolol, Labetalol, Metoprolol


Hackett LP, Wojnar-Horton RE, Dusci LJ, et al. Excretion of sotalol in breast milk. Br J Clin Pharmacol 1990;29:277-8. Letter. PMID: 2306424. [PMC free article: PMC1380099] [PubMed: 2306424]
Riant P, Urien S, Albengres E, et al. High plasma protein binding as a parameter in the selection of betablockers for lactating women. Biochem Pharmacol. 1986;35:4579–81. [PubMed: 2878668]
Atkinson HC, Begg EJ, Darlow BA. Drugs in human milk: Clinical pharmacokinetic considerations. Clin Pharmacokinet. 1988;14:217–40. [PubMed: 3292101]
O'Hare MF, Murnaghan GA, Russell CJ, et al. Sotalol as a hypotensive agent in pregnancy. Br J Obstet Gynaecol. 1980;87:814–20. [PubMed: 7426541]
Wagner X, Jouglard J, Moulin M, et al. Coadministration of flecainide acetate and sotalol during pregnancy: Lack of teratogenic effects, passage across the placenta, and excretion in human breast milk. Am Heart J. 1990;119:700–2. [PubMed: 1689933]
Ho TK, Moretti ME, Schaeffer JK, et al. Maternal beta-blocker usage and breast feeding in the neonate. Pediatr Res. 1999;45(4, pt. 2):67A–Abstract 385. [CrossRef]
Boutroy MJ, Bianchetti G, Dubruc C, et al. To nurse when receiving acebutolol: Is it dangerous for the neonate? Eur J Clin Pharmacol. 1986;30:737–9. [PubMed: 3770068]
Schimmel MS, Eidelman AI, Wilschanski MA, et al. Toxic effects of atenolol consumed during breast feeding. J Pediatr. 1989;114:476–8. [PubMed: 2921694]
Board JA, Fierro RJ, Wasserman AJ, et al. Effects of alpha- and beta-adrenergic blocking agents on serum prolactin levels in women with hyperprolactinemia and galactorrhea. Am J Obstet Gynecol. 1977;127:285–7. [PubMed: 556882]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding


Antihypertensive Agents

Adrenergic Beta-Antagonists


Disclaimer: Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.

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Attribution Statement: LactMed is a registered trademark of the U.S. Department of Health and Human Services.

Bookshelf ID: NBK501165PMID: 30000224


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