Red flags — call us immediately or go to the Emergency Department if:
- Very hard to wake or extremely sleepy (sedation)
- Stiff arms or legs, or trembling in limbs (extrapyramidal signs)
- Poor suck or refusing feeds
- Fewer than 6 wet nappies per day — feeding concern
- Any breathing difficulty or blue lips — universal RED flag
- A rash that does NOT fade when you press a clear glass on it — sepsis sign
- Fever in a baby under 3 months (any temperature ≥ 38.0 °C)
- A fit/seizure, or your child becomes floppy or unresponsive — general red flag
What risperidone is
Risperidone is an atypical antipsychotic. It is used to treat schizophrenia, bipolar disorder, and other conditions involving psychosis. It works by blocking dopamine and serotonin receptors in the brain. It is usually taken once or twice a day and comes in tablets, liquid, or as a long-acting injection given every two weeks or monthly.
How much risperidone passes into breast milk
Risperidone and its main active metabolite both pass into breast milk. Published studies show the combined amount your baby receives is roughly 2–9 % of your weight-adjusted daily dose. This falls in the caution range — not zero, but low enough that most lactation experts say breastfeeding can continue with careful monitoring. The long-acting injection form is harder to reduce quickly, so that requires closer specialist discussion.
An unusual effect: risperidone raises your milk supply
Risperidone strongly increases the hormone prolactin. This can lead to more milk than usual — sometimes much more. While this sounds positive, over-supply can cause engorgement, blocked ducts, or mastitis. If your breasts feel very full, painful, or you notice a fever, contact us.
What to watch for in your baby
The main concerns are: unusual sleepiness or difficulty waking for feeds, poor feeding or weak suck, and — less commonly — muscle stiffness or trembling in the limbs. These are the same kinds of effects the medicine has in adults, but in much smaller amounts in a baby. Most breastfed babies whose mothers take risperidone at standard doses show no problems. However, newborns and very young infants are most at risk and should be monitored closely.
Your medication is important — never stop without advice
Risperidone is essential for your mental health. Stopping it suddenly can cause your condition to return quickly — and caring for a baby while unwell is very difficult and dangerous. If you have concerns about risperidone and breastfeeding, speak to your psychiatrist. They can discuss the dose, timing, or an alternative if needed.
If anything changes
Risperidone passes into breast milk in small amounts. Watch your baby for unusual sleepiness, muscle stiffness, or poor feeding, and watch your own breasts for over-supply. Never stop risperidone without talking to your psychiatrist first.
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Message us on WhatsAppReviewed and signed off by Dr Didier Decamps on 24 September 2026. This is general information and does not replace an individual assessment by a qualified clinician.
Written with AI assistance. Reviewed, corrected and signed by Dr Didier Decamps, paediatrician.
Last reviewed: 24 September 2026