Methenamine use while Breastfeeding

Drugs containing Methenamine: Uribel, Hiprex, Urelle, Cystex, Hyophen, Uta, Urogesic Blue, Urin D/S, Ustell, Urex, Show all 57 »Phosphasal, Mandelamine, Uretron DS, Prosed DS, Utira-C, Uro Blue, MHP-A, Methylphen, Urimax, Urised, Uramit MB, Usept, Urimar-T, Uro-458, Uroqid-Acid No2, Uretron, Hyolev MB, Uro-Phosphate, Uro-L, Visqid AA, Utac, Indiomin MB, UroAv-81, UroAv-B, Urolet MB, Azuphen MB, Uro-MP, UR N-C, Cystemms-V, Urapine, MSP-Blu, Dolsed, Atrosept, Urisedamine, Trac Tabs 2x, Uritin, Uritact DS, Utira, Darcalma, Darpaz, Phosenamine, Uritact-EC, UTICAP, Prosed EC, UriSym, Utrona, Utrona-C

Methenamine Levels and Effects while Breastfeeding

Summary of Use during Lactation

Both the hippurate and mandelate salts of methenamine pass into milk in small quantities and appear acceptable to use, even while nursing a newborn.

Drug Levels

Maternal Levels. Six mothers nursing newborn infants were given methenamine hippurate 1 g orally. Five hours after the dose, a mean methenamine concentration of 7 mg/L was found in milk. In two other women, milk concentrations averaged 9.1 mg/L 2 to 3 hours after a 1 g dose of methenamine hippurate orally and 4.3 mg/L 6 to 7 hours after the dose. Based on the amount of milk ingested, the authors calculated the dose the infants received to be 0.05 to 0.1 mg/kg which is about 1% of the adult dose.[1]

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

Effects in Breastfed Infants

Four newborn infants were allowed to breastfeed in one study after a maternal dose of 1 gram of methenamine hippurate. No adverse effects were reported.[1]

Effects on Lactation and Breastmilk

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

Alternate Drugs to Consider

Methenamine Hippurate, Methenamine Mandelate

References

1. Allgen LG, Holmberg G, Persson B et al. Biological fate of methenamine in man. Acta Obstet Gynecol Scand. 1979;58:287-93. PMID: 484222

Methenamine Identification

Substance Name

Methenamine

CAS Registry Number

100-97-0

Drug Class

Antiinfective Agents, Urinary

Antibacterial Agents

Administrative Information

LactMed Record Number

175

Last Revision Date

20130907

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