Yaz 28 Drug Interactions: What to Avoid and What to Tell Your Doctor

Yaz 28 can interact with several medications, supplements, and herbal products. Some interactions can reduce the effectiveness of Yaz 28 as a contraceptive, potentially leading to unintended pregnancy. Others can increase potassium levels to dangerous heights, or affect the levels of other drugs you're taking. Here's what you need to know.

Category 1: Drugs That Can Make Yaz 28 Less Effective (Reduced Contraceptive Efficacy)

These medications can speed up the metabolism of Yaz 28's hormones in the liver, reducing their levels in your bloodstream and potentially allowing ovulation to occur. If you take any of these, talk to your prescriber about using backup contraception (condoms) and whether you need a different birth control method:

Rifampin / rifabutin — antibiotics used for tuberculosis and other infections; one of the strongest reducers of oral contraceptive efficacy. Use non-hormonal backup contraception during and for 28 days after taking rifampin.

Anticonvulsants / antiepileptics: Carbamazepine (Tegretol), phenytoin (Dilantin), phenobarbital, primidone, topiramate, and lamotrigine can all reduce oral contraceptive hormone levels. Use backup contraception; some anticonvulsants require alternative birth control entirely.

Bosentan (Tracleer) — a pulmonary arterial hypertension medication that reduces contraceptive hormone levels. Use additional non-hormonal contraception.

St. John's Wort (Hypericum perforatum) — an herbal supplement for depression that can significantly reduce contraceptive hormone levels. This interaction is serious and often overlooked because St. John's Wort is sold over the counter. If you take it, tell your prescriber.

Griseofulvin — an antifungal medication used for certain nail and scalp infections; may reduce oral contraceptive efficacy.

Category 2: Drugs That Raise Potassium (Hyperkalemia Risk)

Because drospirenone has anti-mineralocorticoid activity (similar to spironolactone), it can raise serum potassium levels. Combining Yaz 28 with other medications that also increase potassium creates an additive risk of hyperkalemia — dangerously high potassium. These interactions are especially important for patients on chronic medications:

ACE inhibitors (lisinopril, enalapril, ramipril) — used for high blood pressure, heart failure, kidney disease; raise potassium levels independently

Angiotensin II receptor blockers (ARBs) (losartan, valsartan, irbesartan) — also used for hypertension and heart conditions; raise potassium

Potassium-sparing diuretics (spironolactone, amiloride, eplerenone, triamterene) — diuretics that specifically retain potassium

NSAIDs (long-term, daily use) (ibuprofen, naproxen) — when taken daily for chronic conditions, NSAIDs can raise potassium. Occasional use is less concerning.

Heparin — an anticoagulant that can raise potassium with prolonged use

Potassium supplements or salt substitutes — over-the-counter supplements that directly add potassium; avoid unless directed by a doctor

If you take any of these medications chronically, your prescriber should check your serum potassium during the first treatment cycle of Yaz 28.

Category 3: Drugs Whose Levels Are Affected by Yaz 28

Yaz 28 can also affect the metabolism and effectiveness of other medications you take:

Lamotrigine (Lamictal) — used for epilepsy and bipolar disorder. Oral contraceptives can significantly reduce lamotrigine blood levels, potentially increasing seizure risk in epilepsy patients. Conversely, stopping the pill can cause lamotrigine levels to spike dangerously. Work with your neurologist/psychiatrist before starting or stopping Yaz 28.

Thyroid hormone (levothyroxine) — oral contraceptives can increase thyroid hormone-binding proteins, which may require dose adjustments for patients on thyroid hormone replacement therapy.

Certain antifungals (fluconazole, ketoconazole, itraconazole) — these CYP3A4 inhibitors can increase hormone levels of ethinyl estradiol and drospirenone. Generally not a safety concern, but worth knowing about.

What About Antibiotics and Yaz 28?

This is one of the most common questions. The FDA's current guidance states that most commonly prescribed antibiotics (amoxicillin, azithromycin, doxycycline, etc.) do NOT meaningfully reduce oral contraceptive effectiveness. The concern about antibiotics and birth control pills largely dates to older case reports and anecdote. The one major exception is rifampin — which definitely does reduce contraceptive efficacy significantly and should always prompt backup contraception.

That said, always tell your prescriber you're on Yaz 28 any time a new medication is prescribed — including antibiotics — so they can check for interactions.

What to Tell Every Doctor and Pharmacist

Every time you see a new provider, fill a new prescription, or start a new supplement, mention that you take Yaz 28 (or drospirenone/ethinyl estradiol). Provide a complete medication list including OTC drugs, vitamins, and herbal products. For a broader look at Yaz 28 risks, see our guide on Yaz 28 side effects.