50 Participants Needed

Cimetidine Excretion During Lactation

MH
Overseen ByMary Hebert, PharmD, FCCP
No Placebo GroupAll trial participants will receive the active study treatment (no placebo)
Prior Safety DataThis treatment has passed at least one previous human trial

Trial Summary

Will I have to stop taking my current medications?

Yes, you may need to stop taking certain medications. The trial excludes participants taking medications that interact with cimetidine or affect specific drug transporters. It's best to discuss your current medications with the trial team to see if any need to be stopped.

What data supports the effectiveness of the drug cimetidine when excreted in breast milk?

Research shows that cimetidine is actively transported into breast milk at higher concentrations than expected, but it appears safe for infants as the amount they ingest is small. Additionally, studies in animals indicate that high concentrations of cimetidine in milk do not harm the suckling pups or affect milk composition.12345

Is cimetidine safe for breastfeeding mothers and their infants?

Cimetidine is excreted into breast milk, but the amount ingested by a breastfeeding infant is estimated to be 6.7% of the maternal dose, which appears to be safe under normal conditions. Studies in rats also showed no harmful effects on suckling pups or milk composition.12678

How does the drug cimetidine differ from other treatments for its condition?

Cimetidine is unique because it is actively transported into human milk, unlike most drugs that passively diffuse. This active transport mechanism results in higher concentrations in milk, which may have implications for breastfeeding mothers and their infants.123910

What is the purpose of this trial?

This is a prospective, non-randomized, phase I study design evaluating the in vivo activities and expression of OCT1 and BCRP in mammary gland of lactating women at three time points postpartum.

Research Team

MH

Mary Hebert, PharmD, FCCP

Principal Investigator

University of Washington

Eligibility Criteria

This trial is for healthy, lactating or pregnant women planning to breastfeed, aged 18-50, and their nursing infants between 3 weeks to 8 months old. Participants must not be on medications that could interact with the study drug.

Inclusion Criteria

I am a healthy woman aged 18-50, currently breastfeeding or planning to, with a nursing infant aged 3 weeks to 8 months.

Exclusion Criteria

Following multiple gestation (twins, triplets etc.)
You are a smoker.
Pregnancy
See 2 more

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive a single oral dose of cimetidine 200 mg on each of 3 study days at different postpartum stages

6-8 months
3 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

Treatment Details

Interventions

  • Drug Excretion in Breast Milk
Trial Overview The study is testing how Cimetidine (200 MG), a medication commonly used to treat heartburn and stomach ulcers, is excreted in breast milk at different times after childbirth.
Participant Groups
1Treatment groups
Experimental Treatment
Group I: Healthy Lactating WomenExperimental Treatment1 Intervention
Healthy Lactating Women will be studied on 3 study days and serve as their own control.

Find a Clinic Near You

Who Is Running the Clinical Trial?

University of Washington

Lead Sponsor

Trials
1,858
Recruited
2,023,000+

Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Collaborator

Trials
2,103
Recruited
2,760,000+

Findings from Research

Cimetidine transfer into human milk is significantly higher than what would be expected from passive diffusion, indicating the presence of an active transport mechanism, with a milk/serum ratio of 5.77 compared to a predicted ratio of 1.05.
The estimated dose of cimetidine that a suckling infant receives is about 6.7% of the maternal dose, which suggests that it may be safe for breastfeeding mothers under normal conditions.
Active transport of cimetidine into human milk.Oo, CY., Kuhn, RJ., Desai, N., et al.[2013]
Cimetidine and ranitidine were found to be excreted in high concentrations into rat milk, with cimetidine levels significantly exceeding plasma concentrations, indicating a strong transfer to milk.
Despite the high levels of these medications in milk, there were no harmful effects observed on the suckling pups or on the overall composition and synthesis of the milk, suggesting safety in this context.
Excretion of high concentrations of cimetidine and ranitidine into rat milk and their effects on milk composition and mammary gland nucleic acid content.Dostal, LA., Weaver, RP., Schwetz, BA.[2019]
Cimetidine transfers into milk in both rabbits and rats, with a higher concentration in milk compared to serum, indicating that nursing offspring may be exposed to significant levels of the drug.
The mechanism of cimetidine transfer differs between species: in rabbits, it appears to be primarily through diffusion, while in rats, it may involve active transport, suggesting species-specific pharmacokinetics.
Pharmacokinetics of cimetidine during lactation: species differences in cimetidine transport into rat and rabbit milk.McNamara, PJ., Burgio, D., Yoo, SD.[2013]

References

Active transport of cimetidine into human milk. [2013]
Excretion of high concentrations of cimetidine and ranitidine into rat milk and their effects on milk composition and mammary gland nucleic acid content. [2019]
Pharmacokinetics of cimetidine during lactation: species differences in cimetidine transport into rat and rabbit milk. [2013]
The pharmacokinetics and metabolism of cimetidine in neonates. [2019]
Dose-related and other effects of maternal cimetidine pretreatment during lactation on drug metabolism in mouse dams and pups. [2018]
A fully validated method for the simultaneous determination of 11 antihistamines in breast milk by gas chromatography-mass spectrometry. [2018]
Antihistamine use during breastfeeding with focus on breast milk transfer and safety in humans: A systematic literature review. [2022]
Drug use during breast-feeding. [2004]
Active transport of nitrofurantoin into rat milk. [2019]
10.United Statespubmed.ncbi.nlm.nih.gov
Active transport of cimetidine and ranitidine into the milk of Sprague Dawley rats. [2013]
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