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Toremifene

SERM · Antineoplastic agent

Also known as Toremifene citrate, Fareston

SERMAntineoplastic agentATC null
CDSCO approvedSchedule H
EXCRETION
—
not curated
INTERACTIONS
12 major
SEVERE in our sources
PREGNANCY
Avoid
FDA category + note
Top interactionssee all 12 →
  • Agents That Prolong QtSevereTextbookG&G 14e · p1441, 1447
  • AbarelixSevereDatabaseDDInter
  • AbirateroneSevereDatabaseDDInter
  • AdenosineSevereDatabaseDDInter

Mechanism

Toremifene is a Selective Estrogen Receptor Modulator (SERM) that alters the conformation of estrogen receptors (ERs), thereby changing interactions with co-activators and co-repressors. It exhibits anti-estrogenic activity in tissues such as the breast, counteracting estrogenic actions that could be deleterious, particularly in the context of hormone-dependent breast cancer.

Indications

Hormone-dependent metastatic breast cancer in postmenopausal womentreatment of breast cancerMetastatic breast cancer in postmenopausal women with ER+ or of unknown receptor statusDesmoid tumorsBreast cancer (similar to tamoxifen)

Dosing

Adult
60 mg daily by mouth
Hepatic adjustment
Manufacturer advises caution; avoid in severe hepatic failure (risk of decreased elimination)

Contraindications

  • Bradycardia
  • Electrolyte disturbances (particularly uncorrected hypokalaemia)
  • Endometrial hyperplasia
  • Heart failure with reduced left-ventricular ejection fraction
  • History of arrhythmias
  • QT prolongation
  • Acute porphyrias
  • History of severe thromboembolic disease

Side effects

Common
DizzinessFatigueHot flushHyperhidrosisNauseaOedemaSkin reactionsVaginal dischargeVomitinghot flashesgastrointestinal symptomsheadacheback painpharyngitisAdverse effects similar to tamoxifen (vasomotor symptoms, menstrual irregularities)
Serious
  • Thromboembolism
  • Endometrial cancer
  • Hepatic disorders
  • Uterine haemorrhage
  • Corneal opacity
  • Anaemia
  • Leucopenia
  • Thrombocytopenia
  • Prolongation of the QT interval (rarely)
  • Increased risk of torsades de pointes

Pregnancy & lactation

Pregnancy

Avoid

Lactation

Avoid

Drug interactions

Agents That Prolong Qt
Severe
Textbook

Increased risk of torsades de pointes when coadministered with other agents that prolong the QT interval.

Use with caution and monitor cardiac rhythm. Avoid concomitant use if possible.

Source: G&G 14e · p1441, 1447

Abarelix
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Abiraterone
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Adenosine
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Alfuzosin
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Alimemazine
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Amiodarone
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Amisulpride
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Amitriptyline
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Amoxapine
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Amprenavir
Severe
Database

Drug interaction classified as: metabolism

Source: DDInter

Anagrelide
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Related guidelines

Breast cancer
ICMR · Oncology · 2022
Breast cancer
ESMO · Oncology · 2024
Cervical cancer screening and management
ICMR · Oncology · 2022
Tobacco-related cancer prevention
ICMR · Oncology · 2021
Lung cancer
ESMO · Oncology · 2024

Other SERM drugs

Fulvestrant
0 brands

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Sources: KD Tripathi 7e, Goodman & Gilman 14e, Katzung, BNF·Verified: 2026-05-10 · House clinical team