Is Methamphetamine safe while breastfeeding?

Effects on the breastfed infant

A 2-month-old infant whose mother used illicit street methamphetamine recreationally by nasal inhalation was found dead 8 hours after a small amount of breastfeeding and ingestion of 120 to 180 mL of formula. The infant's serum methamphetamine concentration on autopsy was 39 mcg/L. Although the infant's mother was convicted of child endangerment for the use of methamphetamine during breastfeeding, the role that methamphetamine played in the infant's death has been questioned because of the low infant serum methamphetamine concentration and the mother's alleged minimal breastfeeding.[ 9 , 10 ] South Australian government pathologists reported the death of a breastfed infant who was co-sleeping with its mother. Methamphetamine was found in a significant concentration in the infant on autopsy and the drug in breastmilk was thought to be potentially contributory to the death. These authors also reported that in prior deaths of infants under 12 months of age, detectable methamphetamine and its metabolite, amphetamine, may have been partially obtained via breastmilk.[ 11 ] Pathologists from the New Zealand government confirmed similar findings in their country.[ 12 ] Two deaths were reported over 10 years in Taiwan in breastfed infants who were exposed to methamphetamine in breastmilk. One was a 3-month-old male infant who died with a postmortem methamphetamine blood level of 0.142 mg/L. The other was a one-month-old female who had postmortem levels of 0.023 mg/L of methamphetamine and 0.014 g/dL of alcohol. The cause of death was sudden infant death syndrome.[ 13 ]

Effects on milk supply

A single oral dose of 0.2 mg/kg to a maximum of 17.5 mg of d-methamphetamine was given to 6 subjects (4 male and 2 female). Serum prolactin concentrations were unchanged over a period of 300 minutes after the dose.[ 14 ] In 2 papers by the same authors, 20 women with normal physiologic hyperprolactinemia were studied on days 2 or 3 postpartum. Eight received dextroamphetamine 7.5 mg intravenously, 6 received 15 mg intravenously and 6 who served as controls received intravenous saline. The 7.5 mg dose reduced serum prolactin by 25 to 32% compared to control, but the difference was not statistically significant. The 15 mg dose significantly decreased serum prolactin by 30 to 37% at times after the infusion. No assessment of milk production was presented. The authors also quoted data from another study showing that a 20 mg oral dose of dextroamphetamine produced a sustained suppression of serum prolactin by 40% in postpartum women.[ 15 , 16 ] A study compared 31 methamphetamine-dependent subjects to 23 non-dependent subjects. The serum prolactin concentrations in the methamphetamine-dependent subjects were elevated at days 2 and 30 of abstinence. The elevation was greater in women than in men.[ 17 ] The maternal prolactin level in a mother with established lactation may not affect her ability to breastfeed. In a retrospective Australian study, mothers who used intravenous amphetamines during pregnancy were less likely to be breastfeeding their newborn infants at discharge than mothers who abused other drugs (27% vs 42%). The cause of this difference was not determined.[ 18 ] A prospective, multicenter study followed mothers who used methamphetamine prenatally (n = 204) to those who did not (n = 208). Infants exposed to methamphetamine exhibited poor suck, excessive suck and more jitteriness compared to nonexposed infants. Mothers who used methamphetamine were less likely to breastfeed their infants (38%) at hospital discharge than those who did not use methamphetamine

Levels in milk

Methamphetamine is metabolized to several metabolites, including the active metabolite, amphetamine. Maternal Levels. Two nursing mothers who were intravenous methamphetamine abusers collected milk samples just before methamphetamine injection and every 2 to 6 hours after injection for 24 hours. Because the drugs were illicit street drugs, the doses of methamphetamine were not known. Peak and average milk methamphetamine concentrations were about 160 mcg/L and 111 mcg/L in one woman and 610 mcg/L and 281 mcg/L in the other, respectively. Milk methamphetamine concentrations fell with half-lives of 13.6 and 7.4 hours, respectively. Amphetamine, thought to be derived from metabolism of methamphetamine, was present in relatively constant concentrations in the milk of both mothers, averaging 4 and 15 mcg/L, respectively. The authors estimated that the infants would have received daily dosages of 16.7 and 42.2 mcg/kg of methamphetamine and 0.8 and 2.5 mcg/kg of amphetamine, respectively.[ 7 ] These estimated mg/kg infant doses of methamphetamine are lower than therapeutic doses of the equipotent dextroamphetamine for older children with attention deficit hyperactivity disorder. However, this is not evidence of safety for breastfed infants because the data on these two women cannot be extrapolated to other methamphetamine abusers. Thirty-three mothers in Thailand were identified who had predelivery urine drug screens positive for methamphetamine. On average they used methamphetamine 2.4 times per week, primarily by smoking crushed tablets. Of these, 22 had undetectable postpartum methamphetamine milk levels. Of the 11 mothers with methamphetamine in breastmilk, only two mothers had more than 1 consecutive milk samples containing methamphetamine that were analyzed. The mothers had smoked methamphetamine (dosage uncertain) 53 and 68 hours prior to delivery, respectively. First milk samples contained 142 and 345 mcg/L of methamphetamine in the two mothers. The half-lives of m

Alternatives LactMed lists

• Dextroamphetamine
• Lisdexamfetamine
• Methylphenidate