Is Amlodipine safe while breastfeeding?

Effects on the breastfed infant

A woman took amlodipine for hypertension 5 mg daily beginning 2 weeks postpartum. Her exclusively breastfed infant was examined regularly and at 3 months of age was healthy and had normal physical and neurological development.[ 5 ] One woman received amlodipine 2.5 mg orally twice daily during pregnancy for hypertension associated with glomerulonephritis. The dose was increased to 5 mg twice daily on day 2 postpartum. Her exclusively breastfed infant's growth was normal throughout the first year of life and no adverse effects were noted.[ 6 ] A preterm infant of 32 weeks gestation was breastfed exclusively from day 7 to day 20 postpartum. The infant's mother was taking amlodipine and labetalol in unspecified dosages for hypertension. The infant had apnea episodes unrelated to amlodipine. Growth at 2 months of age was slightly low.[ 4 ] Thirty-one women with pregnancy-induced hypertension postpartum received amlodipine 5 mg daily by mouth, with the dosage increased as needed to maintain blood pressure of 140/90 mm Hg or less. Their breastfed (extent not stated) infants exhibited no observed adverse cardiovascular effects within 3 weeks postpartum, although exact measurement methods were not stated.[ 1 ]

Effects on milk supply

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

Levels in milk

Maternal Levels. Thirty-one postpartum women with pregnancy-induced hypertension received amlodipine 5 mg daily by mouth, with the dosage increased as needed to maintain blood pressure of 140/90 mm Hg or less. The final mean dosage for the group was 6 mg (0.099 mg/kg) daily. Simultaneous predose maternal blood and breastmilk samples were obtained within 3 weeks postpartum, after at least 6 days of therapy. The median milk concentration was 11.5 mcg/L (intraquartile range 9.8 to 18 mcg/L). The authors calculated a median infant dosage of 4.2 mcg/kg (intraquartile range 3.1 to 6.3 mcg/kg), which corresponds to a weight-adjusted maternal dosage of 4.2% (intraquartile range 3.1 to 7.3%). However, using the median milk concentration, one would calculate an infant dosage of only 1.73 mcg/kg daily and a weight-adjusted relative dosage of 1.7%. It is unclear why the difference exists between reported and calculate values. In 5 mothers, the weight-adjusted maternal dosage was above 10%, with a maximum value of 15.2% in one mother.[ 1 ] All of these calculations are suboptimal because only single points of maternal plasma and milk concentrations were measured rather than using an area-under-the-curve to calculate them. Six mothers were taking amlodipine 5 mg daily during pregnancy and postpartum. On the second day postpartum, 6 colostrum samples were obtained at 4, 6, 8, 12, 15 and 24 hours following the dose. Amlodipine was undetectable ( 0.1 mcg/L) in all samples.[ 2 ] Eight mothers with infants 5 to 7 days old were taking amlodipine 2.5 mg (1 subject) or 5 mg (7 subjects) daily. They donated foremilk samples at various times after the dose. Peak concentrations in milk occurred from 4 to 8 hours after a dose and ranged from 8 to 20 mcg/L in 5 women with more than 4 milk samples. The weight-adjusted maternal dosage averaged 3.3% (range 1.6% to 4.3%) among the 8 mothers.[ 3 ] Infant Levels. A preterm infant of 32 weeks gestation was breastfed exclusively from day 7 to day 20

Alternatives LactMed lists

• Nifedipine
• Nitrendipine