Drug reference
An anti-oestrogen which induces gonadotrophin release by occupying oestrogen receptors in the hypothalamus, thereby interfering with feedback mechanisms; chorionic gonadotrophin is sometimes used as an adjunct in the treatment of female infertility.
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Pre- and perimenopausal women with oestrogen- receptor-positive breast cancer not previously treated with tamoxifen ▶BY MOUTH ▶Adult: 20 mg daily Anovulatory infertility ▶BY MOUTH ▶Adult: Initially 20 mg daily on days 2, 3, 4 and 5 of cycle, if necessary the daily dose may be increased to 40 mg then 80 mg for subsequent courses; if cycles irregular, start initial course on any day, with subsequent course starting 45 days later or on day 2 of cycle if menstruation occurs Gynaecomastia [prevention in men undergoing long-term bicalutamide treatment, if radiotherapy unsuccessful] ▶BY MOUTH ▶Adult: 20 mg once weekly Breast cancer [chemoprevention in women at moderate- to-high risk] ▶BY MOUTH ▶Adult: 20 mg daily for 5 years l UNLICENSED USE Tamoxifen may be used as detailed below, although these situations are considered outside the scope of its licence: . g the prevention of gynaecomastia in men h.
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Treatment of infertility contra- indicated if personal or family history of idiopathic venous thromboembolism or genetic predisposition to thromboembolism
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Acute porphyrias p. 1120
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Patient decision aids Taking tamoxifen to reduce the chance of developing breast cancer: premenopausal women at Immune system and malignant disease moderately increased risk; Taking tamoxifen to reduce the chance of developing breast cancer: premenopausal women at high risk. National Institute for Health and Care Excellence. March 2017. www.nice.org.uk/about/what-we-do/our-programmes/nice- guidance/nice-guidelines/shared-decision-making
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→Appendix 1: tamoxifen
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▶Common or very common Alopecia. anaemia. cataract. cerebral ischaemia. constipation. diarrhoea. dizziness. embolism and thrombosis. fatigue. fluid retention. headache. hepatic disorders. hot flush. hypersensitivity. hypertriglyceridaemia. muscle complaints. nausea. neoplasms. retinopathy. sensation abnormal. skin reactions. taste altered. uterine disorders. vaginal haemorrhage. vomiting. vulvovaginal disorders ▶Uncommon Hypercalcaemia. interstitial pneumonitis. leucopenia. pancreatitis. thrombocytopenia. vision disorders ▶Rare or very rare Agranulocytosis. angioedema. corneal changes. cutaneous lupus erythematosus. cutaneous vasculitis. cystic ovarian swelling. nerve disorders. neutropenia. radiation recall reaction. Stevens-Johnson syndrome. tumour flare ▶Frequency not known Amenorrhoea SIDE-EFFECTS, FURTHER INFORMATION Endometrial changes Increased endometrial changes, including hyperplasia, polyps, cancer, and uterine sarcoma reported; prompt investigation required if abnormal vaginal bleeding including menstrual irregularities, vaginal discharge, and pelvic pain or pressure in those receiving (or who have received) tamoxifen. Risk of thromboembolism Tamoxifen can increase the risk of thromboembolism particularly during and immediately after major surgery or periods of immobility (consider interrupting treatment and initiating anticoagulant measures).
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Unless being used in the treatment of female infertility, effective contraception must be used during treatment and for 2 months after stopping. Patients being treated for infertility should be warned that there is a risk of multiple pregnancy (rarely more than twins).
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Avoid—possible effects on fetal development.
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Suppresses lactation. Avoid unless potential benefit outweighs risk.
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There can be variation in the licensing of different medicines containing the same drug. Forms available from special-order manufacturers include: oral suspension, oral solution Oral solution ▶Tamoxifen (Non-proprietary) Tamoxifen (as Tamoxifen citrate) 2 mg per 1 ml Tamoxifen 10mg/5ml oral solution sugar free sugar-free | 150 ml P £39.14 DT = £35.00 Tablet ▶Tamoxifen (Non-proprietary) Tamoxifen (as Tamoxifen citrate) 10 mg Tamoxifen 10mg tablets | 30 tablet P £47.21 DT = £38.11 Tamoxifen (as Tamoxifen citrate) 20 mg Tamoxifen 20mg tablets | 30 tablet P £13.00 DT = £5.02 Tamoxifen (as Tamoxifen citrate) 40 mg Tamoxifen 40mg tablets | 30 tablet P £64.88 DT = £63.95
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Endometrial changes Patients should be informed of the risk of endometrial cancer and told to report relevant symptoms promptly. Thromboembolism Patients should be made aware of the symptoms of thromboembolism and advised to report sudden breathlessness and any pain in the calf of one leg.
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20 mg daily
First-line fragment. Read the complete Indications and Dose section above.
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Initially 20 mg daily on days 2, 3, 4 and 5 of
First-line fragment. Read the complete Indications and Dose section above.
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20 mg once weekly
First-line fragment. Read the complete Indications and Dose section above.
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20 mg daily for 5 years
First-line fragment. Read the complete Indications and Dose section above.
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