Drug interactions
Amobarbital + Norethisterone
Severity: Major
Amobarbital and Norethisterone: major 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
Barbiturates induce hepatic enzymes and can lower norethisterone concentrations. This may lead to breakthrough bleeding and contraceptive failure.
What this interaction means in plain words
Amobarbital and Norethisterone 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.
Amobarbital belongs to Central Nervous System; Norethisterone belongs to Endocrine.
Why it happens
Amobarbital induces CYP3A4 and other hepatic enzymes, increasing the clearance of norethisterone.
What to do
Use a non-hormonal or non-enzyme-dependent contraceptive method such as a copper IUD or injectable. Continue extra protection for several weeks after stopping the barbiturate.
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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Other interactions of Norethisterone
- Acitretin + Norethisterone Contraindicated
- Apalutamide + Norethisterone Major
- Belzutifan + Norethisterone Major
- Bosentan + Norethisterone Major
- Brigatinib + Norethisterone Major
- Carbamazepine + Norethisterone Major
Other interactions of Amobarbital
- Amobarbital + Calcium / magnesium / potassium / sodium oxybates Contraindicated
- Amobarbital + Doravirine Contraindicated
- Amobarbital + Elbasvir / grazoprevir Contraindicated
- Amobarbital + Isavuconazonium Contraindicated
- Amobarbital + Isocarboxazid Contraindicated
- Amobarbital + Lonafarnib Contraindicated
Frequently asked questions
Can I take Amobarbital with Norethisterone?
MediHelp rates the interaction as major. Amobarbital and Norethisterone 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. Barbiturates induce hepatic enzymes and can lower norethisterone concentrations. This may lead to breakthrough bleeding and contraceptive failure.
How serious is the interaction between Amobarbital and Norethisterone?
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 non-hormonal or non-enzyme-dependent contraceptive method such as a copper IUD or injectable. Continue extra protection for several weeks after stopping the barbiturate.
What other medicines interact with Norethisterone?
MediHelp also lists interactions of Norethisterone with, for example, Acitretin, Apalutamide, Belzutifan. The full list is on the Norethisterone page.
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