Drug interactions
Ethinyl estradiol-drospirenone + Phenobarbital
Severity: Major
Ethinyl estradiol-drospirenone and Phenobarbital: major interaction.
Last updated Sources: Base de donnees publique des medicaments (France)
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
Phenobarbital is an enzyme inducer that lowers contraceptive hormone levels. This raises the risk of ovulation, breakthrough bleeding and unintended pregnancy.
What this interaction means in plain words
Ethinyl estradiol-drospirenone and Phenobarbital can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Induction of CYP3A4 and glucuronidation increases clearance of ethinyl estradiol and drospirenone.
What to do
Use a nonhormonal method such as a copper IUD, or a method not affected by induction. Continue backup contraception for about 4 weeks after stopping phenobarbital.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
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
Frequently asked questions
Can I take Ethinyl estradiol-drospirenone with Phenobarbital?
MediHelp rates the interaction as major. Ethinyl estradiol-drospirenone and Phenobarbital can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Phenobarbital is an enzyme inducer that lowers contraceptive hormone levels. This raises the risk of ovulation, breakthrough bleeding and unintended pregnancy.
How serious is the interaction between Ethinyl estradiol-drospirenone and Phenobarbital?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use a nonhormonal method such as a copper IUD, or a method not affected by induction. Continue backup contraception for about 4 weeks after stopping phenobarbital.
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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