Tamoxifen Side Effects

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Answer the side-effect intent for tamoxifen without diagnosing; distinguish common from serious reactions and give safe next-step/reporting guidance.

Part of cancer treatment side effects.

What is tamoxifen?

Tamoxifen contains the active ingredient Tamoxifen Citrate.

• Active ingredient — Tamoxifen Citrate
• Registration number — 56/21.12/0698
• Registration holder — Aurogen SA (Pty) Ltd

It is approved for:

• TREMOFID belongs to a group of medicines called anti-oestrogens and is used for the treatment of breast cancer

Common side effects of tamoxifen

Not everyone gets side effects. The effects below are those listed in the South African approved leaflet, grouped using the leaflet’s own frequency wording.

Frequent side effects

• non-cancerous growths in the womb, cancer of the lining of the womb. this may cause pain or pressure in the pelvis (lower tummy) or irregular vaginal bleeding
• Weight gain
• Headaches
• Dizziness
• Hot flushes
• Coughing
• Nausea
• Stomach pain
• Leg cramps
• Bone pain
• Period irregularities
• Vaginal bleeding/discharge
• Itching of the genital area
• Water retention
• Weakness
• Hair loss
• Stroke/ DVT (deep vein thrombosis)
• anaemia (a blood condition which means you have too few red blood cells)
• itching of genitals

Less frequent side effects

• Increase in blood calcium levels (hypercalcaemia). This may cause loss of appetite, nausea and vomiting, tiredness, weakness and muscle pain
• Dry cough and shortness of breath (Interstitial pneumonitis)
• Pancreatitis (pain or tenderness in your upper abdomen), mostly in patients with increased levels of fat in the blood before treatment with TREMOFID
• Swelling of the face, lips, tongue or throat, difficulty in swallowing or breathing (angioedema)
• Stevens -Johnson syndrome (a rare, serious disorder of the skin and mucous membranes, usually a reaction to medication)
• Inflammation of small blood vessels in the skin leading to skin rash (cutaneous vasculitis)
• Bullous pemphigoid(large, fluid-filled blisters)
• Erythema multiforme(bull’s-eye-shaped lesions)
• Inflammation of the skin characterised by rash or erythema, very often on areas exposed to light (a condition called cutaneous lupus erythematosus)
• Presence of tissue similar to the lining of the uterus at other sites in the pelvis (endometriosis)
• Sharp dull pain in the lower abdomen accompanied by bloating and swelling. This may be due to swelling of the ovarian cyst
• Non-cancerous mass in the inner lining of the vagina (called vaginal polyp)
• Blisters on skin that’s exposed to the sun, including the hands, face, and arms( Porphyria cutanea tarda)
• Radiation recall- a tissue reaction that develops on skin that previously received radiation therapy
• Cataracts
• Stroke
• Blood clots
• Lung disease
• Cancers of the uterus (womb)
• Liver problems
• Increase fat in the blood
• Lack of white blood cells (neutropenia)

Frequency unknown side effects

• liver cancer
• loss of appetite
• depression, confusion
• cerebrovascular accidents, (a loss of blood flow to part of the brain, which damages brain tissue)
• dizziness
• inflammation of the vein, cough
• swelling due to retained fluid
• severe increase in bone and tumour pain
• Weight gain
• stomach aches

Serious side effects and warning signs

This leaflet does not set out a separate list of serious side effects. The general warning signs below apply to any medicine.

General warning signs that apply to any medicine

How long can side effects last?

How long a side effect lasts depends on the effect, the product, how long it has been used, and the person. Some effects ease within days as the body adjusts. Others continue for as long as the product is used. A few can persist after stopping, and some need review rather than waiting.

• Settling effects — mild effects that ease over the first days or weeks of use
• Ongoing effects — effects that continue while the product is being used and improve after stopping
• Persistent effects — effects that continue after stopping and need medical review
• Delayed effects — effects that appear after weeks or months rather than immediately

Which of these applies to a particular effect is a clinical question. If a side effect is not settling, is getting worse, or is affecting your daily life, that is worth a conversation with a pharmacist or doctor regardless of how long it has been going on.

Factors that may affect side effects

The approved leaflet identifies the following cautions and factors.

Do not use it at all if

• If you are hypersensitive (allergic) to tamoxifen or any of the ingredients of TREMOFID (listed in section 6)
• If you are pregnant or if you are breastfeeding
• If you are taking any anticoagulants (blood thinning agents) such as warfarin
• If you are a women with a personal or family history of thromboembolism (blood clots),venous thromboembolism (or blood clots in the vein of the leg), stroke

Use with care, and tell your doctor, if

• If you have a history of stroke or blood clot
• If you have liver disease
• If you have high cholesterol or triglycerides ( a type of fat in the blood)
• If you have a history of cataracts
• if you have a history of deep vein thrombosis (blood clots in the veins of your legs), pulmonary embolism (blood clots in your lungs) or any clotting disorders. If you become aware of such events you should contact your doctor
• if you have low levels of white blood cells or platelets in your blood. This can make you bruise more easily, get serious infections, or feel very tired or breathless
• if you have high levels of calcium in your blood. Signs of this include feeling very thirsty, feeling sick (nausea) and vomiting Tell your doctor immediately if you notice any of the following once you start treatment with TREMOFID:
• Vaginal bleeding
• New breast lumps
• Pelvic pain or pressure
• Changes in your vision If you are not sure if any of the above apply to you, talk to your doctor or pharmacist before taking TREMOFID. Children and adolescents TREMOFID has not been studied in children or adolescents and therefore should not be used in this patient population. Other medicine and TREMOFID: Always tell your healthcare professional if you are taking any other medicine (this includes complementary or traditional medicines). The use of TREMOFID with these medicines may cause undesirable interactions. In particular tell your doctor if you are using the following medicines:
• To thin your blood – eg. Warfarin
• Chemotherapy
• Letrozole (used for breast cancer)
• Anastrozole(used for breast cancer)
• Bromocriptine (used for pituitary tumours, increased prolactin in the blood)
• Rifampicin
• Medroxyprogesterone (contraceptive medicine)
• Aminoglutethimide

Pregnancy and breastfeeding

• If you are pregnant or breastfeeding, think you may be pregnant or are planning to have a baby, please consult your doctor, pharmacist or other healthcare provider for advice before taking this medicine
• You should not get pregnant while taking TREMOFID or for two months after stopping treatment with TREMOFID
• Use a barrier contraceptive method or non-hormonal contraception (eg
• condoms, diaphragm, spermicides, intrauterine devices), to prevent pregnancy
• TREMOFID may harm your unborn baby if you are pregnant
• Do not breastfeed your baby while taking TREMOFID

What to do if you experience side effects

If you think you are having a side effect, the response depends on how severe it is. Use the warning signs above first — if any of those apply, treat it as urgent.

If the symptom is severe or frightening

Get medical help immediately. Call 10177 for an ambulance, or 112 from a mobile phone, or go to the nearest emergency department. Take the product and its packaging with you if you can.

If the symptom is mild but bothering you

• Write down what the symptom is, when it started, and how it relates to when you take the product
• Check the leaflet that came with the product to see whether the symptom is listed
• Speak to your pharmacist — for many questions this is the fastest route to a useful answer
• Contact the prescriber if the symptom is affecting your daily life or is not settling

You can also report a suspected side effect in South Africa. Reporting does not replace getting medical advice, and you do not need to be certain the product was the cause.

When to seek urgent medical help

Some symptoms need medical attention straight away rather than an appointment in a few days. Do not wait to see whether they settle.

Get same-day medical advice if you have

• A high fever, or a rash together with feeling generally unwell
• Yellowing of the eyes or skin, or unusually dark urine
• Unusual bruising or bleeding that you cannot explain
• Severe or persistent vomiting or diarrhoea, especially if you cannot keep fluids down
• A sudden change in mood, or thoughts of harming yourself
• Any symptom that is rapidly getting worse

How to report a suspected side effect in South Africa

South Africa has an official system for reporting suspected side effects, run by the South African Health Products Regulatory Authority (SAHPRA). Reports from the public and from healthcare professionals are how safety signals get detected after a product is already in use.

Who can report

Anyone can report — you do not have to be a healthcare professional, and you do not need to prove that the product caused the problem. A suspicion is enough. Patients, caregivers and family members can all submit a report.

What to have ready

• The name of the product, its strength and form, and the batch number if you have it
• Why it was being used, and when it was started and stopped
• What the suspected reaction was, when it began, and how long it lasted
• Any other medicines, supplements or remedies being used at the same time
• Basic details about the person affected — age and sex are usually enough

How to report

SAHPRA accepts adverse reaction reports through its e-Services reporting system and through the Med Safety mobile app. Healthcare professionals can also report through the same routes. Current forms and access points are published on the SAHPRA site.

• SAHPRA Health Products Vigilance — the main vigilance and reporting hub
• SAHPRA e-Services — current adverse reaction reporting access

For a fuller walkthrough see how to report an adverse drug reaction.

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