Distribution and excretion of sumatriptan in human milk

Abstract

1 The excretion of a 6 mg subcutaneous dose of sumatriptan in breast milk was studied in five lactating volunteer subjects with a mean age of 27.6 years and a mean body weight of 75 kg. Drug concentrations in milk and plasma over the ensuing 8 h were measured by high‐performance liquid chromatography. 2 The mean milk:plasma ratio estimated from the areas under the milk and plasma concentration‐time curves (AUC) was 4.9 (95% CI 4.1–5.7), indicating a significant transfer of sumatriptan into the milk compartment. 3 The mean total recovery of drug in milk was estimated to be only 14.4 μg (95% CI 6.1–22.7 μg), or 0.24% of the 6 mg administered dose. On a weight‐adjusted basis this corresponded to a mean infant exposure of 3.5% of the maternal dose (95% CI 0.3–6.7%). 4 If oral bioavailability in the infant is similar to that in adults (14%), the weight‐adjusted infant dose is reduced to 0.49%. Furthermore, allowance for reduced clearance in the infant predicts an infant exposure varying from 4.9% in a very premature neonate to 0.7% in a 30 week old infant. 5 Since sumatriptan is usually administered as a single dose at infrequent intervals, the low level of excretion in breast milk suggests that continued breast feeding following its use will not pose a significant risk to the suckling infant. Even this minor exposure could be largely avoided by expressing and discarding all milk for 8 h after the dose.

Use of Common Migraine Treatments in Breast‐Feeding Women: A Summary of Recommendations

“…A published study of 5 lactating women showed no adverse pediatric events. 21 LRC L3. Briggs category: probably compatible.…”

Pharmacological treatment of migraine during pregnancy and breastfeeding

“…One study including five lactating women treated with a single, subcutaneous dose of sumatriptan found that the estimated RID was only 3.5%, suggesting that use of sumatriptan during lactation should not pose a substantial risk to the infant. 107 The Summary of Product Characteristics for sumatriptan Box 1 | Breastfeeding and relative infant dose Relative infant dose (RID) 101 is the weight-adjusted dose of a drug received by the infant via breast milk, expressed as a percentage of the weight-adjusted maternal dose.…”

Medication use in the treatment of migraine during pregnancy and lactation

“…Sumatriptan and eletriptan levels have been measured in human milk. For sumatriptan, the M/P ratio was 4.9:1, with 0.21% of peak plasma dose measured at 8 hours after 6 mg of the subcutaneous dose was given [33]. Eletriptan had an M/P ratio of 1:4, with 0.02% of an 80-mg dose measured at 24 hours [32].…”