Drug interactions
Ethinyl estradiol-levonorgestrel + Trimethoprim
Severity: Minor
Ethinyl estradiol-levonorgestrel and Trimethoprim: minor interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Antibacterials have been theorised to reduce contraceptive efficacy by disrupting gut flora involved in estrogen recirculation. Evidence of reduced hormone levels or contraceptive failure with trimethoprim is lacking.
What this interaction means in plain words
Ethinyl estradiol-levonorgestrel and Trimethoprim have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Ethinyl estradiol-levonorgestrel belongs to Endocrine; Trimethoprim belongs to Anti Bacterial.
Why it happens
Theoretical reduction of enterohepatic recycling of ethinyl estradiol through altered gut flora; not well substantiated.
What to do
No routine change is required. Counsel on missed pills and on gastrointestinal illness.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Ethinyl estradiol-levonorgestrel
- Ethinyl estradiol-levonorgestrel + Fezolinetant Contraindicated
- Ethinyl estradiol-levonorgestrel + Ombitasvir / paritaprevir / ritonavir and dasabuvir Contraindicated
- Ethinyl estradiol-levonorgestrel + Tranexamic acid Contraindicated
- Aminocaproic acid + Ethinyl estradiol-levonorgestrel Major
- Amobarbital + Ethinyl estradiol-levonorgestrel Major
- Anastrozole + Ethinyl estradiol-levonorgestrel Major
Other interactions of Trimethoprim
Frequently asked questions
Can I take Ethinyl estradiol-levonorgestrel with Trimethoprim?
MediHelp rates the interaction as minor. Ethinyl estradiol-levonorgestrel and Trimethoprim have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Antibacterials have been theorised to reduce contraceptive efficacy by disrupting gut flora involved in estrogen recirculation. Evidence of reduced hormone levels or contraceptive failure with trimethoprim is lacking.
How serious is the interaction between Ethinyl estradiol-levonorgestrel and Trimethoprim?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No routine change is required. Counsel on missed pills and on gastrointestinal illness.
What other medicines interact with Ethinyl estradiol-levonorgestrel?
MediHelp also lists interactions of Ethinyl estradiol-levonorgestrel with, for example, Fezolinetant, Ombitasvir / paritaprevir / ritonavir and dasabuvir, Tranexamic acid. The full list is on the Ethinyl estradiol-levonorgestrel page.
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