Drugs Channel
Topics & Medications
Quicklinks
Related Channels
Arcalyst and Breastfeeding
Because no research has been done on breastfeeding and Arcalyst (rilonacept), it is unknown whether the drug passes through breast milk or if it would cause problems in a nursing infant. Due to the unknown risks, the manufacturer of the drug recommends that women use this medication with caution while nursing and be watchful for any unusual side effects in the child.
Arcalyst® (rilonacept) is a prescription medication used to treat a type of autoinflammatory condition in children and adults. It is given as a once-a-week injection just beneath the skin (subcutaneously).
At this time, it is unknown if Arcalyst passes through breast milk. The manufacturer recommends it be used cautiously in breastfeeding women. If you are nursing a child, talk with your healthcare provider before using this medication.
No research has been done on Arcalyst and breastfeeding. Therefore, very little information is available on the possible effects of using this medication while nursing. It is unknown if the drug passes through breast milk, or if it would harm a nursing infant.
Although this lack of information is certainly frustrating, it is important to understand that studies of medications are rarely done in breastfeeding women, as this would usually expose an infant who will not directly benefit from the medication to possible risks.
Arcalyst decreases the body's immune response, and may increase the risk for potentially serious infections. Therefore, if your healthcare provider recommends Arcalyst, you should carefully observe your child for any possible signs of infection, and report such signs to your child's healthcare provider. Possible signs of infection include but are not limited to:
- Fever
- Poor feeding
- Breathing difficulty
- Excessive crying
- Irritability
- Sleeping more than usual
- Skin rash
- Pale skin.
Written by/reviewed by: Susan Lakey, PharmD, MPH, BCPP
Last reviewed by: Kristi Monson, PharmD



