Sronyx 28 Day Drug Interactions: What You Need to Know

If you take Sronyx 28 Day — or any of its equivalent generics like Vienva, Aubra, Lutera, or Aviane — certain medications, supplements, and even foods can interfere with how well it works. Some interactions reduce your birth control's effectiveness, potentially putting you at risk of unintended pregnancy. Others can cause dangerous side effects.

This guide covers the major and moderate interactions you should know about, plus what to tell your doctor.

How Drug Interactions Work with Birth Control

Sronyx 28 Day contains two hormones: Levonorgestrel 0.1 mg (a progestin) and Ethinyl Estradiol 0.02 mg (an estrogen). These hormones are processed by your liver using a group of enzymes called cytochrome P450 (especially CYP3A4).

Most drug interactions with oral contraceptives happen in one of two ways:

1. Another drug speeds up your liver enzymes (enzyme induction): This causes your body to break down the hormones in Sronyx faster than normal, lowering their levels in your blood. Result: reduced contraceptive effectiveness.
2. Sronyx affects the other drug: The estrogen or progestin in Sronyx can alter how your body processes other medications, increasing or decreasing their levels.

Understanding this helps you see why certain medications are problematic — and why "just taking them at different times" doesn't fix the issue.

Medications That Interact with Sronyx 28 Day

Major Interactions (Use Backup or Alternative Contraception)

These medications significantly reduce the effectiveness of Sronyx. If you take any of these, you may need a non-oral contraceptive method or additional backup:

• Rifampin (Rifadin) and other Rifamycins: This is the most well-documented interaction. Rifampin is a powerful CYP3A4 inducer that can reduce contraceptive hormone levels by up to 40%. If you're prescribed Rifampin for tuberculosis or other infections, use a non-hormonal backup method (like condoms) throughout treatment and for at least 28 days after stopping.
• Anticonvulsants (seizure medications):
  • Phenytoin (Dilantin)
  • Carbamazepine (Tegretol)
  • Phenobarbital
  • Topiramate (Topamax) — at doses above 200 mg/day
  • Oxcarbazepine (Trileptal)
  • Felbamate (Felbatol)
  All of these induce liver enzymes and can reduce Sronyx's effectiveness. If you take any of these for epilepsy or another condition, talk to your neurologist and OB/GYN about alternative contraception.
• St. John's Wort: This popular herbal supplement for mood is a potent CYP3A4 inducer. It can significantly reduce the levels of both hormones in Sronyx. Do not take St. John's Wort while on any combined oral contraceptive.
• Hepatitis C medications — Ombitasvir/Paritaprevir/Ritonavir (with or without Dasabuvir): This combination is contraindicated with Sronyx. Taking them together can cause dangerous elevations in liver enzymes (ALT). If you need Hepatitis C treatment, your doctor must switch you to a different contraceptive method.
• Modafinil (Provigil) and Armodafinil (Nuvigil): These wakefulness-promoting agents used for narcolepsy and shift work disorder can reduce contraceptive effectiveness through enzyme induction. Use backup contraception during treatment and for one month after stopping.
• Bosentan (Tracleer): Used for pulmonary arterial hypertension, Bosentan induces CYP3A4 and reduces oral contraceptive effectiveness.
• Griseofulvin: This antifungal medication may reduce the effectiveness of oral contraceptives. Use backup contraception during treatment.
• HIV protease inhibitors and NNRTIs: These medications used in HIV treatment have variable effects on oral contraceptive levels. Some (like Ritonavir) decrease hormone levels, while others may increase them. Work closely with your HIV specialist and gynecologist to determine the best approach.

Moderate Interactions (Monitor Closely)

These interactions are less severe but still important to know about:

• Antibiotics (Ampicillin, Tetracyclines): The clinical significance of the antibiotic-birth control interaction is debated among experts. While large studies suggest most antibiotics don't significantly reduce contraceptive effectiveness, many doctors still recommend using backup contraception during antibiotic courses as a precaution — especially for short courses where the stakes of an unintended pregnancy are high.
• Lamotrigine (Lamictal): This interaction works in reverse — Sronyx reduces Lamotrigine levels, potentially triggering breakthrough seizures. If you take Lamotrigine for epilepsy or bipolar disorder, your dose may need to be adjusted when starting or stopping oral contraceptives. This requires close monitoring by your neurologist.
• Thyroid hormones (Levothyroxine, Synthroid): COCs can increase thyroid-binding globulin, which may require an increase in your thyroid medication dose. If you take thyroid medication, have your levels checked after starting birth control.
• Prednisolone and other corticosteroids: Sronyx can increase corticosteroid levels in your blood. This is usually not clinically significant but may matter if you're on high-dose or long-term steroids.

Supplements and Over-the-Counter Products to Watch

Not all interactions come from prescription drugs. Be aware of these:

• St. John's Wort: Listed above under major interactions — this is the most important supplement to avoid. It's available over the counter and many women don't realize it interacts with birth control.
• Vitamin C: High doses (1,000 mg+) may slightly increase estrogen levels. This is generally not dangerous but is worth mentioning to your doctor.
• Activated charcoal: Sometimes taken for detox purposes, charcoal can bind to medications in your stomach and reduce absorption — including your birth control pill. Avoid taking charcoal within 2 hours of your pill.

Food and Drink Interactions

• Grapefruit juice: Grapefruit can modestly increase estrogen levels by inhibiting CYP3A4 (the opposite of enzyme inducers). For most women, this isn't clinically significant — an occasional glass of grapefruit juice is fine. However, large daily quantities might slightly increase estrogen-related side effects.
• Alcohol: Alcohol doesn't directly interact with Sronyx's effectiveness. However, heavy drinking can impair your ability to remember to take your pill on time, and vomiting after drinking can affect absorption.

What to Tell Your Doctor

When seeing any healthcare provider — not just your prescriber — make sure they know you're taking an oral contraceptive. Here's a checklist:

• List all medications: Include prescription drugs, OTC medications, vitamins, and herbal supplements (especially St. John's Wort).
• Mention your birth control specifically: Some doctors may not think to check for contraceptive interactions when prescribing other medications.
• Ask about interactions: When prescribed a new medication, specifically ask: "Will this affect my birth control?"
• Tell your pharmacist too: Pharmacists are excellent at catching drug interactions. They can flag potential issues when filling new prescriptions.
• Don't stop medications on your own: If you discover a potential interaction, don't stop either medication without talking to your doctor first. They can help you find the safest solution.

If you take Lamotrigine, make sure both your neurologist and your prescribing OB/GYN or primary care doctor are aware of the interaction — dose adjustments may be needed.

Final Thoughts

Drug interactions with Sronyx 28 Day are manageable — but only if you know about them. The biggest risks come from Rifampin, certain seizure medications, St. John's Wort, and specific Hepatitis C drugs. If you take any of these, you'll need backup contraception or an alternative birth control method entirely.

For moderate interactions like antibiotics or Lamotrigine, the solution is usually monitoring and communication between your healthcare providers.

The bottom line: always tell every doctor and pharmacist that you're on oral contraceptives, and always ask about interactions when starting something new. For more on Sronyx 28 Day, see our complete overview or find where it's available at Medfinder.