The Basics
What is Atenolol?
Used to treat angina and hypertension; also used to lower the risk of death after a heart attack.
Brand names for Atenolol
Tenormin
How Atenolol is classified
Antihypertensive Agents, Adrenergic Beta-Antagonists, Antiarrhythmics
Atenolol During Pregnancy
Atenolol pregnancy category
Category DNote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.
What we know about taking Atenolol while pregnant
Atenolol can cause fetal harm when administered to apregnant woman. Atenolol crosses the placental barrier andappears in cord blood. Administration of atenolol, starting inthe second trimester of pregnancy, has been associated withthe birth of infants that are small for gestational age. Nostudies have been performed on the use of atenolol in the firsttrimester and the possibility of fetal injury cannot be excluded.If this drug is used during pregnancy, or if the patient becomespregnant while taking this drug, the patient should be apprisedof the potential hazard to the fetus.
Taking Atenolol While Breastfeeding
What are recommendations for lactation if you're taking Atenolol?
Because of atenolol’s relatively extensive excretion into breastmilk and its extensive renal excretion, other agents may be preferred while nursing a newborn or preterm infant or with high maternal dosages.[1][2] Infants older than 3 months of age appear to be at little risk of adverse effects from atenolol in breastmilk. Timing breastfeeding with respect to the time of the atenolol dose appears to be of little benefit in reducing infant atenolol exposure because the time of the peak is unpredictable.[3]
Maternal / infant drug levels
Because of atenolol’s relatively extensive excretion into breastmilk and its extensive renal excretion, other agents may be preferred while nursing a newborn or preterm infant or with high maternal dosages.[1][2] Infants older than 3 months of age appear to be at little risk of adverse effects from atenolol in breastmilk. Timing breastfeeding with respect to the time of the atenolol dose appears to be of little benefit in reducing infant atenolol exposure because the time of the peak is unpredictable.[3]
Possible effects of Atenolol on milk supply
One unusual case of oligomenorrhea, hyperprolactinemia and galactorrhea was reported in a 38-year-old woman who had been taking atenolol for about 18 months. Prolactin values returned to normal within 3 days of discontinuation of atenolol. Galactorrhea slowly lessened and disappeared one month after atenolol discontinuation.[19]
Possible alternatives to Atenolol
Propranolol, Labetalol, Metoprolol.
List of References
Lactation sources: Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK501922/1. Eidelman AI, Schimmel MS. Drugs and breast milk. Pediatrics. 1995;95:956-7. Letter. PMID: 7761234
2. Hale TW. Medications in breastfeeding mothers of preterm infants. Pediatr Ann. 2003;32:337-47. PMID: 12774709
3. Eyal S, Kim JD, Anderson GD et al. Atenolol pharmacokinetics and excretion in breast milk during the first 6 to 8 months postpartum. J Clin Pharmacol. 2010;50:1301-9. PMID: 20145263
4. 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. PMID: 2878668
5. White WB, Andreoli JW, Wong SH et al. Atenolol in human plasma and breast milk. Obstet Gynecol. 1984;63 (Suppl 1):42S-4S. PMID: 6700880
6. Kulas J, Lunell NO, Rosing U et al. Atenolol and metoprolol. A comparison of their excretion into human breast milk. Acta Obstet Gynecol Scand Suppl. 1984;Suppl 118:65-9. PMID: 6587730
7. Bhamra RK, Thorley KJ, Vale JA et al. High-performance liquid chromatographic measurement of atenolol: methodology and clinical applications. Ther Drug Monit. 1983;5:313-8. PMID: 6636259
8. Thorley KJ, McAinsh J. Levels of the beta-blockers atenolol and propranolol in the breast milk of women treated for hypertension in pregnancy. Biopharm Drug Dispos. 1983;4:299-301. PMID: 6626704
9. Schimmel MS, Eidelman AI, Wilschanski MA et al. Toxic effects of atenolol consumed during breast feeding. J Pediatr. 1989;114:476-8. PMID: 2921694
10. Atkinson HC, Begg EJ, Darlow BA. Drugs in human milk. Clinical pharmacokinetic considerations. Clin Pharmacokinet. 1988;14:217-40. PMID: 3292101
11. Hebert MF, Carr DB, Anderson GD et al. Pharmacokinetics and pharmacodynamics of atenolol during pregnancy and postpartum. J Clin Pharmacol. 2005;45:25-33. PMID: 15601802
12. Lwin EMP, Gerber C, Leggett C et al. Estimation of atenolol transfer into milk and infant exposure during its use in lactating women. J Hum Lact. 2018;34:592-9. PMID: 29870669
13. Liedholm H. Transplacental passage and breast milk accumulation of atenolol in humans. Drugs. 1983;25 (Suppl 2):217-8.
14. Liedholm H, Melander A, Bitzen PO et al. Accumulation of atenolol and metoprolol in human breast milk. Eur J Clin Pharmacol. 1981;20:229-31. PMID: 728604
15. Fowler MB, Brudenell M, Jackson G et al. Essential hypertension and pregnancy: successful outcome with atenolol. Br J Clin Pract. 1984;38:73-4. PMID: 6704301
16. Holt DW, Bhamra R, Thorley KJ et al. High performance liquid chromatographic measurement of atenolol: placental transfer and expression in breast milk. Br J Clin Pharmacol. 1982;14:148P-9P. PMC: PMC1427566
17. Ho TK, Moretti ME, Schaeffer JK et al. Maternal a-blocker usage and breast feeding in the neonate. Pediatr Res. 1999;45:67A. Abstract 385.
18. Liedholm H, Wahlin-Boll E, Hanson A et al. Transplacental passage and breast milk concentration of hydralazine. Eur J Clin Pharmacol. 1982;21:417-9. PMID: 7200428
19. Lee ST. Hyperprolactinemia, galactorrhea, and atenolol. Ann Intern Med. 1992;116:522. Letter. PMID: 1739249
Disclaimer: This material is provided for educational purposes only and is not intended for medical advice, diagnosis, or treatment. Consult your healthcare provider with any questions.
