The Basics
What is Mexiletine?
Used to treat abnormal heart rhythms, chronic pain, and some causes of muscle stiffness.
Brand names for Mexiletine
Mexitil
How Mexiletine is classified
Antiarrhythmics
Mexiletine During Pregnancy
Mexiletine pregnancy category
Category CNote 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 Mexiletine while pregnant
N/A
Taking Mexiletine While Breastfeeding
What are recommendations for lactation if you're taking Mexiletine?
Limited information indicates that maternal doses of mexiletine up to 600 mg daily produce low levels in milk and would not be expected to cause any adverse effects in breastfed infants, especially if the infant is older than 2 months. Because of the relative lack of data concerning breastfeeding during maternal mexiletine therapy, exclusively breastfed infants should be carefully monitored if this drug is used during lactation, possibly including measurement of serum levels to rule out toxicity if there is a concern.
Maternal / infant drug levels
Limited information indicates that maternal doses of mexiletine up to 600 mg daily produce low levels in milk and would not be expected to cause any adverse effects in breastfed infants, especially if the infant is older than 2 months. Because of the relative lack of data concerning breastfeeding during maternal mexiletine therapy, exclusively breastfed infants should be carefully monitored if this drug is used during lactation, possibly including measurement of serum levels to rule out toxicity if there is a concern.
Possible effects of Mexiletine on milk supply
Relevant published information was not found as of the revision date.
Possible alternatives to Mexiletine
None listed
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. Lewis AM, Patel L, Johnston A et al. Mexiletine in human blood and breast milk. Postgrad Med J. 1981;57:546-7. PMID: 7329891
2. Timmis AD, Jackson G, Holt DW. Mexiletine for control of ventricular dysrhythmias in pregnancy. Lancet. 1980;2:647-8. Letter. PMID: 6107439
3. Monfort A, Martin B, Boucoiran I et al. Feasibility study of drugs quantification in breast milk by liquid chromatography coupled to mass spectrometry (LC-MS/MS). Birth Defects Res. 2019 ;111 (9 Special Issue):558. Abstract.
4. Lownes HE, Ives TJ. Mexiletine use in pregnancy and lactation. Am J Obstet Gynecol. 1987;157:446-7. PMID: 3618696
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.
