Meprobamate

Drug Levels and Effects:




Summary of Use during Lactation:


If meprobamate is required by the mother, it is not necessarily a reason to discontinue breastfeeding. However, because there is little published experience with meprobamate during breastfeeding, other agents may be preferred, especially while nursing a newborn or preterm infant, or when other drugs that can cause sedation are used simultaneously.


Drug Levels:


Maternal Levels.

One author reported a personal communication from the manufacturer. The manufacturer reports that 6 lactating women who were given a single 800 mg oral dose of meprobamate had peak milk meprobamate concentrations 4 hours after the dose.[1]

The muscle relaxant carisoprodol is metabolized to meprobamate. A mother taking carisoprodol 700 mg three times daily during pregnancy and lactation had trough breastmilk levels of carisoprodol and meprobamate measured before the first morning dose on 4 consecutive days at steady-state (time postpartum not stated). Average minimum breastmilk levels were 0.9 mg/L for carisoprodol and 11.6 mg/L for meprobamate. The authors calculated that the minimum infant dose of the drug plus metabolite was 1.9 mg/kg daily or 4.1% of the maternal weight-adjusted dosage. Extrapolating these results to an average (rather than minimum) dose, the authors estimated that an exclusively breastfed infant would receive 3 mg/kg daily or 6% of the maternal weight-adjusted dosage.[2]

A woman who was suspected to have been abusing carisoprodol had the drug and meprobamate detectable in breastmilk for 2 consecutive days after hospitalization; only meprobamate was detectable on day 3.[3]

Infant Levels.

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


Effects in Breastfed Infants:


A mother taking carisoprodol 700 mg plus propoxyphene 70 mg andacetaminophen900 mg 3 times daily and partially breastfeeding her infant noticed no unusual behavior or adverse reactions in her infant. The infant grew normally and, at 6 months of age, examination by a pediatrician found normal psychomotor development.[2]


Possible Effects on Lactation:


One paper reported that some psychiatric patients receiving meprobamate alone or in combination with other psychotropic drugs developed galactorrhea. Further details of meprobamate use were not reported.[4]


Alternate Drugs to Consider:


Lorazepam,Oxazepam


References:


1. Ayd FJ. Excretion of psychotropic drugs in human breast milk. Int Drug Ther Newsl. 1973;8:33-40.
2. Nordeng H, Zahlsen K, Spigset O . Transfer of carisoprodol to breast milk. Ther Drug Monit. 2001;23:298-300. PMID:11360042
3. Bailey DN, Briggs JR. Carisoprodol: an unrecognized drug of abuse. Am J Clin Pathol. 2002;117:396-400. PMID:11888078
4. Hooper JH Jr, Welch VC, Shackelford RT. Abnormal lactation associated with tranquilizing drug therapy. JAMA. 1961;178:506-7. PMID:14448766



Substance Identification:




Substance Name:

Meprobamate

CAS Registry Number:

57-53-4

Drug Class:


  • Anti-Anxiety Agents

  • Hypnotics and Sedatives

  • Muscle Relaxants, Central


  • Administrative Information:




    LactMed Record Number:


    593


    Last Revision Date:


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