Recently there have been several questions on the use of Ivabradine in breastfeeding mothers with Postural tachycardia syndrome (POTS ) and I confess I know little about this condition so am simply compiling the information from other sources. https://www.nhs.uk/conditions/postural-tachycardia-syndrome/
“Ivabradine is a hyperpolarization-activated cyclic nucleotide-gated channel blocker indicated to reduce the risk of hospitalization for worsening heart failure in patients with stable, symptomatic chronic heart failure with left ventricular ejection fraction ≤ 35%, who are in sinus rhythm with resting heart rate ≥ 70 beats per minute and either are on maximally tolerated doses of beta-blockers or have a contraindication to beta-blocker use.
Ivabradine blocks the cyclic nucleotide-gated (HCN) channel responsible for the cardiac pacemaker . There are no data on its transfer of this drug into human milk, but the detrimental effects to the foetus are concerning which may carry on into early postpartum periods during breastfeeding. If used, close monitoring by a paediatric cardiologist is suggested.” Hale TW and Krutsch, K. Medications and Mothers Milk Springer Publ. accessed online 15.October 2024
It has a half life of 6 hours (Hale) but e-lactancia quotes 2 hours, but that of its active metabolite S18982 is 11 hours, plasma protein binding 70% but oral bioavailability only 40%
In a 2018 paper Kearney suggests that:
Its molecular weight (467) and protein binding (70 %) suggest that excretion into breast milk would be expected. However, ivabradine has low oral bioavailability (40 %) due to extensive first pass metabolism (Tse 2015). it is unclear what effect, if any, the potentially low levels in breast milk could have on the developing infant. Until more is known about ivabradine in breast milk, it must be used with extreme caution. The infant should be monitored for bradycardia and arrhythmias, and poor feeding and weight gain.
References
Hale TW and Krutsch, K. Medications and Mothers Milk Springer Publ.
Ivabradine and breastfeeding. Are they compatible? (e-lactancia.org)
Choi HY, Noh YH, Cho SH, Ghim JL, Choe S, Kim UJ, Ah Jung J, Bae KS, Lim HS. Evaluation of pharmacokinetic and pharmacodynamic profiles and tolerability after single (2.5, 5, or 10 mg) and repeated (2.5, 5, or 10 mg bid for 4.5 days) oral administration of ivabradine in healthy male Korean volunteers. Clin Ther. 2013 Jun;35(6):819-35.
Kearney L, Wright P, Fhadil S, Thomas M. Postpartum Cardiomyopathy and Considerations for Breastfeeding. Card Fail Rev. 2018
Tse S, Mazzola N. Ivabradine (Corlanor) for Heart Failure: The First Selective and Specific I f Inhibitor. P T. 2015 Dec;40(12):810-4.
