Cyclosporine levels vary considerably in several case reports and series. This variability seems to be partially due to inconsistent sampling times among the reports and probably related to the fat content of the milk at the time of sampling. With typical maternal cyclosporine blood levels, a completely breastfed infant would usually receive no more than about 2% of the mother's weight-adjusted dosage or pediatric transplantation maintenance dosage, and often less than 1%. In most breastfed infants, cyclosporine is not detectable in blood; however, occasionally infants have had detectable blood levels, even when milk levels and infant dosage were apparently low.
Numerous infants have been breastfed during maternal cyclosporine use, usually with a concurrent corticosteroid and sometimes with concurrent azathioprine. At least 2 mothers successfully breastfed a second infant after successfully breastfeeding the first infant. No reports of adverse effects on infants’ growth, development or kidney function have been reported, although thorough follow-up examinations have not always been performed or reported. United States and European expert guidelines, the National Transplantation Pregnancy Registry and other experts consider cyclosporine use to be acceptable during breastfeeding,[1-8] Breastfed infants should be monitored if this drug is used during lactation, possibly including measurement of serum levels to rule out toxicity if there is a concern.[9]
Because absorption from the eye is limited, ophthalmic cyclosporine would not be expected to cause any adverse effects in breastfed infants. To substantially diminish the amount of drug that reaches the breastmilk after using eye drops, place pressure over the tear duct by the corner of the eye for 1 minute or more, then remove the excess solution with an absorbent tissue.