This drug is a rather unusal compound that is ONLY used thus far for treating  Amyotrophic lateral sclerosis.  I was moved that a patient with ALS called and was continuing to breastfeed her infant, and wanted information about this drug in breastfeeding.  We found that levels of Riluzole were quite low.  Thanks to this heroic mom for providing milk samples during this difficult period of her life.  TWH

Title: Estimation of Riluzole Levels in Human Milk and Infant Exposure During Its Use in a Patient With ALS.

Authors: Datta P, Rewers-Felkins K, Aurora N, Baker T, Hale TW.

J Hum Lact. 2018 May;34(2):355-357.

No Abstract available

Table 1: Pharmacokinetic Parameters of Riluzole in Breastfeeding Woman (n=1).

Parameter (units)                              Value

AUC (ng.h/mL)                                1133

C_avg (ng/mL)                                     94.4                

C_max (ng/mL)                                   229.5

_T.max (h)                                            2

Infant dose (μg/kg/day)                    14.1

RID (%)                                            1.6

Note: AUC = Area under the Drug Concentration-Time Curve, C_avg = Average Drug Concentration across the Dose Interval, C_max= Maximum Drug Concentration across the Dose Interval, and T_max= Time at which maximum concentration is observed, RID = Relative Infant Dose for riluzole in Milk %.

Figure 1. Concentration–time profile of riluzole in human milk. (Dose 50 mg BID).

PMID 29100479