Is Myoril (thiocolchicoside) safe for a breastfeeding mother?

Myoril (Thiocolchicoside) Safety During Lactation

Myoril (thiocolchicoside) should NOT be used during breastfeeding, as it is explicitly contraindicated in lactation by the manufacturer and lacks any safety data in nursing mothers. 1

Evidence-Based Contraindication

• Thiocolchicoside is formally contraindicated during lactation according to pharmaceutical industry labeling, with no published data on excretion into breast milk or effects on breastfed infants 1
• The only available human pregnancy data (18 cases) showed no major birth defects, but this study explicitly excluded lactation and provides no information about breastfeeding safety 1
• The contraindication exists because thiocolchicoside has never been studied in breastfeeding women, making risk assessment impossible 1

Clinical Decision Algorithm

When a breastfeeding mother requires muscle relaxation:

• First-line approach: Use acetaminophen or ibuprofen as preferred analgesics during lactation, as both are fully compatible with breastfeeding 2
• If NSAIDs are insufficient: Consider physical therapy, heat/cold application, and non-pharmacologic interventions before any muscle relaxant
• If a muscle relaxant is absolutely necessary: Consult specialized lactation pharmacology resources (LactMed database) for alternatives with established safety profiles 2
• Never use thiocolchicoside: The complete absence of lactation data combined with formal contraindication makes this an unacceptable choice 1

General Principles for Medication Safety in Lactation

• Only a few drugs pose clinically significant risk to breastfed babies; most medications are compatible with breastfeeding when properly selected 3
• Drugs that are absolutely contraindicated during breastfeeding include antineoplastics, drugs of abuse, some anticonvulsants, ergot alkaloids, and radiopharmaceuticals 3
• When prescribing any medication to a breastfeeding mother, select those with the lowest risk to the infant and time dosing before the infant's longest sleep interval 2
• The LactMed database (free online, government-sponsored) provides the most current and authoritative safety information for medications during lactation 2

Critical Pitfall to Avoid

• Do not assume that lack of reported adverse effects means a drug is safe during breastfeeding—thiocolchicoside's contraindication exists precisely because it has never been studied, not because harm has been proven 1
• Physicians must not advise stopping breastfeeding unnecessarily, as this is one of the most common reasons for premature cessation of nursing 4