Kelnor 1/35 28 Day Shortage: What Providers and Prescribers Need to Know in 2026

Patients prescribed Kelnor 1/35 28 Day (ethynodiol diacetate 1 mg / ethinyl estradiol 35 mcg) sometimes encounter difficulty finding it in stock at their pharmacy. While Kelnor 1/35 is not currently on the FDA's drug shortage database, prescribers should be prepared to manage patient concerns about availability, advise on therapeutic substitutes, and document any formulary exceptions that may be needed.

Current Availability Status (2026)

As of 2026, Kelnor 1/35 is not listed on the FDA Drug Shortage Database. The product is manufactured by Teva Pharmaceuticals USA under the brand name Kelnor. Equivalent products include Zovia 1/35E and Valtya 1/35, which contain the same active ingredients (ethynodiol diacetate 1 mg + ethinyl estradiol 35 mcg).

Reported patient difficulty accessing Kelnor 1/35 is primarily a localized pharmacy stocking issue, not a national shortage. Fewer manufacturers producing this formulation (compared to more popular progestin types like norgestimate or norethindrone) means lower stocking priority at some pharmacies.

Pharmacological Profile: What Makes This Formulation Distinctive

Kelnor 1/35 uses ethynodiol diacetate, a progestin that is rapidly converted to norethindrone in vivo. It is classified as a first-generation progestin. Compared to third-generation progestins (norgestimate, desogestrel), ethynodiol diacetate has:

Moderate androgenic activity (lower than levonorgestrel, higher than norgestimate)

Comparable VTE risk to norethindrone-based COCs

No FDA-approved acne or PMDD indication (unlike drospirenone- or norgestimate-containing products)

Standard monophasic dosing (21 active + 7 placebo tablets per cycle)

Therapeutic Substitution Options

When Kelnor 1/35 is unavailable, consider the following therapeutic substitution options in order of clinical similarity:

1. Zovia 1/35E / Valtya 1/35 (Preferred Substitute — Identical Formulation)

Contains ethynodiol diacetate 1 mg / ethinyl estradiol 35 mcg — bioequivalent to Kelnor 1/35. This is the appropriate first-line substitute if the patient must change brands. No clinical bridging or backup contraception required for a same-formulation brand switch.

2. Norethindrone-Based COCs (e.g., Junel Fe, Loestrin, Microgestin)

Since ethynodiol diacetate is metabolized to norethindrone, switching to a norethindrone-containing COC at a similar estrogen dose is pharmacologically rational. The most comparable formulations are norethindrone 1 mg / ethinyl estradiol 35 mcg (Necon 1/35, Norinyl 1+35). If the patient tolerates these, cycle patterns should be similar.

3. Norgestimate-Based COCs (e.g., Sprintec, MonoNessa)

Sprintec (norgestimate 0.25 mg / ethinyl estradiol 35 mcg) is widely available and considered to have a favorable tolerability profile with low androgenic side effects. Appropriate for patients without history of adverse effects on third-generation progestins.

Key Prescribing Considerations During a Transition

If switching to a different progestin type, patients should use backup contraception for the first 7 days of the new formulation.

Counsel patients that breakthrough bleeding is common in the first 1–3 cycles after a formulation change and does not indicate reduced effectiveness.

Document any insurance-required prior authorization for the substitute formulation; many ACA-compliant plans cover all FDA-approved contraceptives without cost sharing.

If the patient has a compelling reason to stay on ethynodiol diacetate specifically (e.g., known tolerance, prior trial-and-error), document this clearly to support any formulary exception request.

Contraindications Reminder for All COCs

Regardless of which formulation is prescribed, ensure patients do not have contraindications to estrogen-containing contraceptives, including:

History of VTE, stroke, or MI

Active or history of breast cancer

Active liver disease or liver tumors

Uncontrolled hypertension

Smoking and age over 35

Current pregnancy

How medfinder Can Help Your Patients

When patients are struggling to locate Kelnor 1/35 at their preferred pharmacy, medfinder can help. Providers can direct patients to medfinder.com/providers to learn how the service works. medfinder contacts pharmacies in the patient's area to verify which ones have the medication in stock, then delivers results by text.

For a complete provider workflow guide, see: How to help your patients find Kelnor 1/35 in stock: A provider's guide.