Comprehensive medication guide to Kelnor 1/35 28 Day including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
$0 under ACA-compliant plans (contraceptive mandate requires no cost sharing); $0–$30 copay on non-ACA plans where it may be Tier 1–2.
Estimated Cash Pricing
$42–$68 retail for a 28-tablet pack; as low as $13.67–$15.91 with GoodRx or SingleCare coupons for a 30-day supply.
Medfinder Findability Score
78/100
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Kelnor 1/35 28 Day is a combination oral contraceptive manufactured by Teva Pharmaceuticals USA. Each active tablet contains 1 mg of ethynodiol diacetate (a progestin) and 35 mcg of ethinyl estradiol (an estrogen). The 28-tablet blister pack contains 21 active light yellow tablets followed by 7 white placebo tablets.
Kelnor 1/35 is the generic successor to the discontinued brand Demulen 1/35. It is FDA-approved for the prevention of pregnancy and is equivalent in formulation to Zovia 1/35E and Valtya 1/35.
When taken correctly and consistently, Kelnor 1/35 is approximately 99% effective with perfect use and about 91% effective with typical use. Beyond contraception, many patients also experience lighter, more regular menstrual periods and reduced menstrual cramps.
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Kelnor 1/35 works through three complementary mechanisms. The primary mechanism is suppression of ovulation: the progestin (ethynodiol diacetate, rapidly metabolized to norethindrone in the body) inhibits the LH surge from the pituitary gland, preventing the ovaries from releasing an egg. The estrogen component (ethinyl estradiol) suppresses FSH, preventing follicle maturation.
As secondary mechanisms, the progestin thickens cervical mucus — creating a physical barrier that prevents sperm from reaching the uterus — and alters the endometrial lining to make it less receptive to implantation. Together, these three mechanisms provide highly effective contraception.
Ethynodiol diacetate is a first-generation progestin with moderate androgenic activity. It was first used in oral contraceptives in the 1960s and has a well-established safety and efficacy record. The 35 mcg ethinyl estradiol dose is a standard low-dose estrogen level found in many combination pills.
1 mg / 35 mcg — tablet
21 active light yellow tablets + 7 white placebo tablets per blister pack (28 tablets total). Take one tablet daily.
As of 2026, Kelnor 1/35 28 Day is not on the FDA Drug Shortage Database. However, patients regularly report difficulty finding it at their usual pharmacy. This is primarily a stocking issue rather than a national supply crisis: because ethynodiol diacetate is a less commonly prescribed progestin, fewer pharmacies maintain consistent inventory of this specific formulation.
The medication is manufactured by Teva Pharmaceuticals, which is the primary supplier. Pharmacies with lower prescription volumes for this product may only reorder it infrequently. Patients are best served by maintaining a 7–10 day buffer and proactively checking availability before running out.
If you're struggling to find Kelnor 1/35 at your local pharmacy, medfinder calls pharmacies near you to check which ones have your prescription in stock, then texts you the results.
Kelnor 1/35 is not a controlled substance, so it can be prescribed by any licensed prescriber in the U.S. No special DEA certification or prescriber registration is required.
OB/GYNs (Obstetrician-Gynecologists)
Primary care physicians (family medicine, internal medicine)
Pediatricians (for patients of appropriate age)
Nurse practitioners (NPs) and physician assistants (PAs) — in most U.S. states
Certified nurse-midwives (CNMs)
Kelnor 1/35 is also widely available through telehealth birth control services such as Nurx, The Pill Club, and Wisp, as well as general telehealth platforms (Teladoc, MDLive). These providers can evaluate patients online and send a prescription to a local pharmacy or by mail.
No. Kelnor 1/35 28 Day is not a controlled substance and is not scheduled by the DEA. It is a standard prescription medication that can be prescribed by any licensed healthcare provider — including OB/GYNs, primary care physicians, nurse practitioners, physician assistants, certified nurse-midwives, and telehealth providers.
Because Kelnor 1/35 is not a controlled substance, it can be prescribed in larger quantities (such as a 90-day supply), called in by phone or electronically, and dispensed at any licensed pharmacy. There are no federal restrictions on refill frequency.
Most side effects are mild and improve within 1–3 months:
Nausea (take with food or at bedtime to reduce)
Breast tenderness or swelling
Breakthrough bleeding or spotting (especially in first 1–3 cycles)
Headache
Mood changes, including possible depressive symptoms
Weight changes (often fluid retention)
Skin darkening (melasma — worsened by sun exposure)
Decreased libido
Serious side effects requiring immediate medical attention:
Blood clots (DVT, pulmonary embolism, stroke, heart attack) — seek emergency care immediately
Sudden vision changes or loss (retinal thrombosis)
Severe abdominal pain (liver problems)
Jaundice (yellowing of skin or eyes)
Severe headache or hypertensive crisis symptoms
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Zovia 1/35E
Identical formulation (ethynodiol diacetate 1 mg / ethinyl estradiol 35 mcg). Bioequivalent brand-name substitute for Kelnor 1/35.
Valtya 1/35
Another brand equivalent containing the same active ingredients as Kelnor 1/35 in the same doses.
Sprintec
Norgestimate 0.25 mg / ethinyl estradiol 35 mcg. Widely available monophasic COC with low androgenic profile.
Necon 1/35
Norethindrone 1 mg / ethinyl estradiol 35 mcg. Pharmacologically rational substitute since ethynodiol diacetate is metabolized to norethindrone.
Yaz
Drospirenone 3 mg / ethinyl estradiol 20 mcg. Anti-androgenic progestin; FDA-approved for PMDD and acne in addition to contraception.
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Rifampin
majorStrongly induces liver enzymes; significantly reduces effectiveness of ethinyl estradiol and progestin. Use backup contraception during treatment and for 1 month after.
Ombitasvir/paritaprevir/ritonavir (HCV regimen)
majorCan cause severe ALT elevations (>20x ULN) when combined with ethinyl estradiol. Discontinue Kelnor before starting this regimen; restart ~2 weeks after completion.
Phenytoin (Dilantin)
moderateInduces hepatic enzymes, reducing contraceptive hormone levels. Use backup contraception.
Carbamazepine (Tegretol)
moderateReduces effectiveness of combined oral contraceptives through enzyme induction.
Phenobarbital
moderateBarbiturate that accelerates metabolism of estrogen and progestin components.
St. John's Wort
moderateHerbal enzyme inducer; reduces blood levels of contraceptive hormones and may cause contraceptive failure.
Griseofulvin
moderateAntifungal that may reduce oral contraceptive efficacy. Use backup contraception during treatment.
Aromatase inhibitors (anastrozole, exemestane)
moderateDirectly oppose the estrogen component of Kelnor 1/35. Generally should not be combined.
Atazanavir (HIV antiretroviral)
moderateComplex interaction: without ritonavir, increases ethinyl estradiol levels; with ritonavir, decreases levels. Discuss with HIV specialist.
Tetracyclines / Ampicillin
minorMinor reduction in contraceptive efficacy possible; evidence is limited. Some providers recommend backup contraception during short antibiotic courses.
Kelnor 1/35 28 Day is a well-established, affordable combination oral contraceptive. It contains ethynodiol diacetate — a first-generation progestin with a long track record — paired with a standard 35 mcg ethinyl estradiol dose. For patients who tolerate this formulation well, it offers reliable pregnancy prevention with predictable cycle control at a low cash cost.
The main challenge is availability: because Kelnor 1/35 uses a less common progestin, it may not be consistently stocked at every pharmacy. Patients should maintain a small supply buffer, know that Zovia 1/35E is a bioequivalent alternative if needed, and take advantage of discount programs to reduce cost.
If you ever have trouble locating Kelnor 1/35 at your pharmacy, medfinder is here to help. We call pharmacies near you to find which ones have your medication in stock, and text you the results.
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Our medication guides are researched and written to help patients make informed decisions. All content is reviewed for accuracy and updated regularly. Learn more about our standards
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