title: 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 micrograms (95% CI 6.1-22.7 micrograms), 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.
authors.affiliation: Department of Pharmacy, King Edward Memorial Hospital for Women, Subiaco, Western Australia.
authors.forename: R E
authors.initials: RE
authors.lastname: Wojnar-Horton
authors.forename: L P
authors.initials: LP
authors.lastname: Hackett
authors.forename: P
authors.initials: P
authors.lastname: Yapp
authors.forename: L J
authors.initials: LJ
authors.lastname: Dusci
authors.forename: M
authors.initials: M
authors.lastname: Paech
authors.forename: K F
authors.initials: KF
authors.lastname: Ilett
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008881:Migraine Disorders / Q000188:drug therapy; D008895:Milk, Human / Q000378:metabolism*; D018170:Sumatriptan / Q000493:pharmacokinetics* / Q000627:therapeutic use
chemical_list: D018170:Sumatriptan