Comprehensive medication guide to Tamoxifen including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
$0–$30 copay for generic tablets; Tier 1–2 on most commercial plans. May be covered at $0 for chemoprevention under ACA preventive care provisions. Medicare Part D covers Tamoxifen with a $2,000 annual out-of-pocket cap.
Estimated Cash Pricing
$20–$110 retail for generic 20 mg (30 tablets); as low as $20–$34 with GoodRx or SingleCare coupons for a 30-day supply. Soltamox oral liquid is more expensive and may require insurance prior authorization.
Medfinder Findability Score
88/100
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Tamoxifen is a selective estrogen receptor modulator (SERM) used to treat and prevent estrogen receptor-positive (ER+) breast cancer in women and men. It works by blocking estrogen receptors in breast tissue, preventing estrogen from stimulating cancer cell growth. Tamoxifen is sold under the brand names Nolvadex (tablet) and Soltamox (oral solution), and is widely available as a generic.
FDA-approved uses include: adjuvant treatment of early and advanced ER-positive breast cancer in both pre- and postmenopausal women and men; treatment of ductal carcinoma in situ (DCIS); breast cancer risk reduction in high-risk women; and prevention of contralateral breast cancer.
Tamoxifen has been in clinical use since the 1970s and appears on the World Health Organization's List of Essential Medicines. It is not a controlled substance and can be prescribed by any licensed provider. The standard dose is 20 mg once daily, taken for 5-10 years depending on indication and individual risk assessment.
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Tamoxifen is a selective estrogen receptor modulator (SERM) that competitively binds to estrogen receptors on breast cancer cells. When tamoxifen occupies the receptor, it forms a nuclear complex that decreases DNA synthesis and blocks estrogen's growth-stimulating signals. Tamoxifen is cytostatic — it halts cancer cell division rather than killing cells outright (cells accumulate in the G0 and G1 phases of the cell cycle).
Tamoxifen is a prodrug: the liver converts it to its most active metabolite, endoxifen, which is 30 to 100 times more potent than the parent compound. This conversion is mediated primarily by the CYP2D6 enzyme. Patients who are poor CYP2D6 metabolizers — either genetically or due to concurrent use of CYP2D6-inhibiting medications like paroxetine or fluoxetine — produce lower endoxifen levels and may have reduced Tamoxifen efficacy.
In tissues other than the breast, Tamoxifen acts differently. In bone, it acts as a partial estrogen agonist, helping preserve bone density (beneficial effect). In uterine tissue, it also has partial agonist activity — which is why long-term Tamoxifen use slightly increases the risk of endometrial cancer (rare but important risk).
10 mg — tablet
Used for risk reduction and some off-label indications; also available as 10 mg/5 mL oral solution
20 mg — tablet
Standard dose for breast cancer treatment and prevention; most commonly dispensed form
10 mg/5 mL — oral solution (Soltamox)
Brand-name liquid formulation; used when swallowing tablets is difficult; requires refrigeration after opening
As of 2026, Tamoxifen is not on the FDA national drug shortage list and is generally widely available from multiple generic manufacturers. Most patients can fill their Tamoxifen prescription without difficulty at major retail pharmacies.
However, localized stock-outs do occur — particularly at chain pharmacies that operate with lean, just-in-time inventory systems. Factors that can cause temporary local shortages include supplier delays from specific generic manufacturers, higher-than-expected local demand, and the growing use of 10-year Tamoxifen protocols that increase total demand per patient.
If you encounter a stock-out at your local pharmacy, medfinder can call pharmacies near you to check real-time availability and text you results, saving you time and frustration. Try independent pharmacies if chain stores are out — they often source from different distributors.
Tamoxifen is not a controlled substance, so it does not require any special DEA registration or prescribing authority beyond a standard medical license. Any licensed prescriber in the United States may write a Tamoxifen prescription.
Telehealth prescribing is available for established Tamoxifen patients in most states. New prescriptions for breast cancer treatment typically require in-person evaluation, but ongoing therapy management and refills are well-suited for telehealth visits.
No. Tamoxifen is not a controlled substance and does not have a DEA schedule. It can be prescribed by any licensed medical provider — including physician assistants, nurse practitioners, and physicians — without special DEA registration or additional prescribing authority beyond a standard medical license.
Because it is not a controlled substance, Tamoxifen prescriptions can be written for 90-day supplies, filled via mail-order pharmacy, called in by a prescriber, or prescribed via telehealth without the additional restrictions that apply to scheduled medications. There are no refill limitations specific to Tamoxifen's scheduling status — standard prescription rules apply.
Most common side effects are related to Tamoxifen's estrogen-blocking activity:
Tamoxifen carries an FDA boxed warning for rare but serious events. Seek immediate medical attention if you experience:
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Anastrozole (Arimidex)
Aromatase inhibitor preferred for postmenopausal women with ER+ breast cancer; generically available and widely used as an alternative or sequential therapy to Tamoxifen
Letrozole (Femara)
Aromatase inhibitor used in postmenopausal women and in combination with ovarian suppression in premenopausal high-risk patients; generic available
Exemestane (Aromasin)
Steroidal aromatase inhibitor; alternative for postmenopausal ER+ breast cancer, especially after non-steroidal AI therapy
Raloxifene (Evista)
SERM approved for breast cancer risk reduction in postmenopausal women; retains ~76% of Tamoxifen's prevention efficacy with fewer uterine side effects
Toremifene (Fareston)
SERM similar to Tamoxifen; FDA-approved for metastatic breast cancer in postmenopausal women when Tamoxifen is not tolerated
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Paroxetine (Paxil)
majorStrong CYP2D6 inhibitor; significantly reduces conversion of Tamoxifen to active metabolite endoxifen, potentially reducing efficacy. Avoid concurrent use.
Fluoxetine (Prozac)
majorStrong CYP2D6 inhibitor; reduces endoxifen levels. Prefer alternative antidepressants with minimal CYP2D6 inhibition.
Warfarin (Coumadin)
majorTamoxifen significantly potentiates anticoagulant effect of warfarin, increasing bleeding risk. Contraindicated in risk-reduction setting; requires close monitoring in treatment setting.
Anastrozole (Arimidex)
majorTamoxifen reduces anastrozole plasma levels. Do not use concurrently — use sequentially only.
Letrozole (Femara)
majorContraindicated concurrent use. These medications are used sequentially, not simultaneously.
St. John's Wort
majorCYP3A4 inducer that significantly reduces Tamoxifen and endoxifen blood levels. Avoid while taking Tamoxifen.
Rifampin
majorStrong CYP3A4/CYP2C9 inducer that decreases Tamoxifen levels. Avoid if possible during Tamoxifen therapy.
Bupropion (Wellbutrin)
moderateCYP2D6 inhibitor; may reduce Tamoxifen efficacy. Consider alternative antidepressants.
Duloxetine (Cymbalta)
moderateModerate CYP2D6 inhibitor; lower risk than paroxetine/fluoxetine but use with caution. Discuss with oncologist.
Diphenhydramine (Benadryl)
moderateOTC CYP2D6 inhibitor found in many allergy and sleep products. Regular use may reduce Tamoxifen efficacy; occasional use likely low risk.
Tamoxifen is one of the most important medications in cancer medicine — a proven, affordable, and well-tolerated therapy that has saved or extended countless lives over five decades of use. For patients with ER-positive breast cancer, consistent long-term adherence to Tamoxifen is closely tied to outcomes, making it essential to address access and cost barriers proactively.
While Tamoxifen is not in a declared national shortage as of 2026, local pharmacy stock-outs remain a reality for some patients. The most effective protective strategies are switching to mail-order pharmacy for 90-day supplies, refilling early, and knowing which nearby pharmacies reliably stock your dose.
If you ever can't find Tamoxifen at your local pharmacy, medfinder will call nearby pharmacies on your behalf and text you which ones have your medication in stock — taking the legwork out of a frustrating situation.
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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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