Sotalol and Breastfeeding

Summary of use during lactation

Because of its extensive excretion into breastmilk and its renal excretion, 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] Infant exposure is predicted to less after the infant is 4 weeks of age or older.

Drug levels in milk and infant serum

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] A physiologically based pharmacokinetic model of sotalol exposure during breastfeeding predicted that infants in the 90th percentile in height and weight had exposures about 20% higher than infants of the same age in the 10th percentile due to increased milk intake. The simulated infant exposures increased throughout the first 2 weeks of life and are maintained at the highest concentrations in weeks 2 to 4, with a consistent decrease observed as infants aged. Simulations suggest that breastfeeding infants will have plasma concentrations in the lower range observed in infants administered sotalol directly. Infant sex and frequency of nursing had minimal effects on exposure.[6] 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.[7] 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.[8,9] A prospective study of pregnant patients taking a beta-blocker asked mothers to complete a questionnaire about postpartum breastfeeding and any side effects in their breastfed infants. One mother reported taking sotalol in an unreported dosage while breastfeeding. She reported weak sucking in her infant.[10]

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.[11]

Alternative drugs to consider

Propranolol, Labetalol, Metoprolol

References

1. Hackett LP, Wojnar-Horton RE, Dusci LJ, et al. Excretion of sotalol in breast milk. Br J Clin Pharmacol 1990;29:277-8.2306424 PubMed
2. 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;35:4579-81.2878668 PubMed
3. Atkinson HC, Begg EJ, Darlow BA. Drugs in human milk: Clinical pharmacokinetic considerations. Clin Pharmacokinet 1988;14:217-40.3292101 PubMed
4. O'Hare MF, Murnaghan GA, Russell CJ, et al. Sotalol as a hypotensive agent in pregnancy. Br J Obstet Gynaecol 1980;87:814-20.7426541 PubMed
5. 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;119:700-2.1689933 PubMed
6. Pressly MA, Schmidt S, Guinn D, et al. Informing a comprehensive risk assessment of infant drug exposure from human milk: Application of a physiologically based pharmacokinetic lactation model for sotalol. J Clin Pharmacol 2023;63 Suppl 1:S106-s16.37317500 PubMed
7. 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. doi:10.1203/00006450-199904020-00402
8. Boutroy MJ, Bianchetti G, Dubruc C, et al. To nurse when receiving acebutolol: Is it dangerous for the neonate? Eur J Clin Pharmacol 1986;30:737-9.3770068 PubMed
9. Schimmel MS, Eidelman AI, Wilschanski MA, et al. Toxic effects of atenolol consumed during breast feeding. J Pediatr 1989;114:476-8.2921694 PubMed
10. Freppel R, Gaboriau L, Richardson M, et al. Beta-blockers and breastfeeding: A real-life prospective study. Eur J Clin Pharmacol 2024;80:1937-43.39259357 PubMed
11. 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;127:285-7.556882