Does Vyvanse Cross the Placental Barrier?
Yes, Vyvanse (lisdexamfetamine) does cross the placental barrier as it is converted to dextroamphetamine after ingestion, and amphetamines are known to cross the placenta. 1, 2
Mechanism of Placental Transfer
- Lisdexamfetamine is a prodrug that is converted to dextroamphetamine in the body after ingestion 2
- Nearly all drugs administered during pregnancy will enter the fetal circulation to some degree via passive diffusion 3
- Drugs with molecular weights less than 500 Daltons typically have complete transfer across the human placenta 4
- Lipid-soluble drugs pass through the placental barrier with greater ease than polar compounds 5
Clinical Implications for Pregnancy
- Limited published information exists specifically on lisdexamfetamine use during pregnancy 1
- The American College of Obstetricians and Gynecologists indicates that information about amphetamines should be applied when considering lisdexamfetamine use in pregnancy 2
- Amphetamines do not appear to be associated with major congenital malformations, including cardiac malformations, or other significant adverse developmental outcomes 1
Potential Risks
- There is a possible increased risk for gastroschisis (adjusted odds ratio 3.0; 95% CI, 1.2-7.4), though this finding comes from one study with possible confounding and represents a small absolute risk given the rarity of gastroschisis (population prevalence of 0.05%) 1
- Possible increased risk for preeclampsia (adjusted relative risk 1.29; 95% CI, 1.11-1.49), though this risk appears to be small 1, 6
- Continued stimulant use in the second half of pregnancy may be associated with a small increased risk of preterm birth (adjusted relative risk 1.30; 95% CI, 1.10-1.55) 1, 6
Monitoring Recommendations
- Close monitoring of both maternal and fetal condition is necessary when using stimulant medications during pregnancy 5
- Monitor infants carefully for irritability, insomnia, and feeding difficulties if the mother was taking amphetamines during pregnancy 1
- The absolute increases in risks are small, suggesting that women with significant ADHD should not necessarily discontinue their treatment based solely on these findings 6
Important Considerations
- Drug interactions at the placenta may affect drug transfer to the fetus without necessarily altering maternal plasma concentrations 7
- The placenta is not just a passive diffusional barrier but also expresses various influx and efflux transporters and drug-metabolizing enzymes that can affect drug transfer 7
- Information provided regarding amphetamine use during pregnancy applies to therapeutic use and does not apply to non-prescribed amphetamine use in persons with stimulant use disorder 1