Drug interactions
Ethinyl estradiol-drospirenone + Trimethoprim
Severity: Moderate
Ethinyl estradiol-drospirenone and Trimethoprim: moderate 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
Trimethoprim alone does not meaningfully reduce contraceptive hormone levels, so the proposed gut flora effect is theoretical. However, trimethoprim can raise serum potassium by blocking renal sodium channels, which may add to drospirenone's potassium-retaining effect.
What this interaction means in plain words
Ethinyl estradiol-drospirenone and Trimethoprim can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Ethinyl estradiol-drospirenone belongs to Endocrine; Trimethoprim belongs to Anti Bacterial.
Why it happens
Trimethoprim blocks distal tubular epithelial sodium channels, reducing potassium excretion, in addition to drospirenone's aldosterone antagonism.
What to do
Check serum potassium during longer courses or in patients with renal impairment or other potassium-raising drugs. No extra contraception is needed for the antibiotic itself.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Ethinyl estradiol-drospirenone
- Ethinyl estradiol-drospirenone + Fezolinetant Contraindicated
- Ethinyl estradiol-drospirenone + Ombitasvir / paritaprevir / ritonavir Contraindicated
- Ethinyl estradiol-drospirenone + Ombitasvir / paritaprevir / ritonavir and dasabuvir Contraindicated
- Ethinyl estradiol-drospirenone + Tranexamic acid Contraindicated
- Aminocaproic acid + Ethinyl estradiol-drospirenone Major
- Amobarbital + Ethinyl estradiol-drospirenone Major
Other interactions of Trimethoprim
Frequently asked questions
Can I take Ethinyl estradiol-drospirenone with Trimethoprim?
MediHelp rates the interaction as moderate. Ethinyl estradiol-drospirenone and Trimethoprim can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Trimethoprim alone does not meaningfully reduce contraceptive hormone levels, so the proposed gut flora effect is theoretical. However, trimethoprim can raise serum potassium by blocking renal sodium channels, which may add to drospirenone's potassium-retaining effect.
How serious is the interaction between Ethinyl estradiol-drospirenone and Trimethoprim?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check serum potassium during longer courses or in patients with renal impairment or other potassium-raising drugs. No extra contraception is needed for the antibiotic itself.
What other medicines interact with Ethinyl estradiol-drospirenone?
MediHelp also lists interactions of Ethinyl estradiol-drospirenone with, for example, Fezolinetant, Ombitasvir / paritaprevir / ritonavir, Ombitasvir / paritaprevir / ritonavir and dasabuvir. The full list is on the Ethinyl estradiol-drospirenone page.
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