Drug Levels and Effects:

Summary of Use during Lactation:

When used epidurally or intravenously during labor or for a short time immediately postpartum, amounts of alfentanil ingested by the neonate are small and would not be expected to cause any adverse effects in breastfed infants.Alfentanilis highly protein bound which should result in less transfer to breastmilk compared to other opiates; however, because there is no published experience with repeated doses of intravenous alfentanil during established lactation, other agents may be preferred, especially while nursing a newborn or preterm infant. If alfentanil is required by the mother, it is not a reason to discontinue breastfeeding, but once the mother's milk comes in, it is best to limit maternal intake and to supplement analgesia with a nonnarcotic analgesic if necessary. If the baby shows signs of increased sleepiness (more than usual), difficulty breastfeeding, breathing difficulties, or limpness, a physician should be contacted immediately.

Drug Levels:

The oral bioavailability of alfentanil is 43% in adults.[1] Therapeutic blood levels of 100 to 300 mcg/L after intravenous administration have been reported in adults. The usual intravenous dosage of alfentanil for neonates and infants is 5 to 20 mcg/kg initially followed by 20 to 30 mcg/kg/hour.Alfentanilis hepatically metabolized to inactive metabolites.

Maternal Levels.

Nine women in the early postpartum period were given intravenous alfentanil 50 mcg initially and then 10 mcg as needed during tubal ligation surgery under general anesthesia. Colostrum was sampled prior to surgery at 4 and 28 hours after the last intraoperative dose. No postoperative doses were given. At 4 hours after the last dose, the average level of alfentanil in colostrum was 0.88 mcg/L and the highest measured level was 1.5 mcg/L.Alfentanilmilk levels 28 hours after the last dose were about the same as presurgery (control) levels; however, average cumulative alfentanil dosage was not reported.[2] Using the highest measured alfentanil level in this study, an exclusively breastfed infant would receive an alfentanil dosage of 0.2 mcg/kg daily.

Infant Levels.

Relevant published information was not found as of the revision date.

Effects in Breastfed Infants:

Relevant published information was not found as of the revision date.

Possible Effects on Lactation:

Narcotics can increase serum prolactin.[3][4] However, the prolactin level in a mother with established lactation may not affect her ability to breastfeed.

Alternate Drugs to Consider:



1. Kharasch ED. Intravenous and oral alfentanil as in vivo probes for hepatic and first-pass cytochrome P450 3A activity: noninvasive assessment by use of pupillary miosis. Clin Pharmacol Ther. 2004;76:452-66. PMID:15536460
2. Giesecke AH, Rice LJ, Lipton JM.Alfentanilin colostrum. Anesthesiology. 1985;63:A284. Abstract.
3. Tolis G, Dent R, Guyda H. Opiates, prolactin, and the dopamine receptor. J Clin Endocrinol Metab. 1978;47:200-3. PMID:263291
4. Frecska E, Perenyi A, Arato M. Blunted prolactin response to fentanyl in depression. Normalizing effect of partial sleep deprivation. Psychiatry Res. 2003;118:155-64. PMID:12798980

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • Analgesics, Opioid

  • Narcotics

  • Anesthetics, Intravenous

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

    Disclaimer:Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.