Eltroxin Side Effects

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

What is Eltroxin?

Eltroxin contains the active ingredient Levothyroxine sodium.

• Active ingredient — Levothyroxine sodium
• Registration number — 52/21.3/0882; 52/21.3/0883; 52/21.3/0884; 52/21.3/0885
• Registration holder — Biotech Laboratories (Pty) Ltd

It is approved for:

• The name of your medicine is MITHYRO
• MITHYRO contains levothyroxine sodium
• This belongs to a group of medicines called thyroid hormones
• MITHYRO is is used to treat hypothyroidism, a disease in which the thyroid gland is underactive and does not produce enough thyroxine, a hormone, which is important for controlling your metabolism

Common side effects of Eltroxin

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.

Reported side effects

• swelling of your hands, feet, ankles, face, lips, mouth or throat, which may cause difficulty in swallowing or breathing
• rash or itching
• These are all very serious side effects. If you have them, you may have had a serious reaction to MITHYRO you may need urgent medical attention or hospitalisation. Tell your doctor immediately or go to the casualty department at your nearest hospital if you notice any of the following:
• chest pain
• heart attack, heart failure (the symptoms include pain or discomfort in one or both arms, the back, neck, jaw or stomach; shortness of breath with or without chest discomfort; other signs such as breaking out in a cold sweat, nausea or lightheadedness)
• seizures or convulsions (fits)
• difficulty in breathing
• changes in the way your heart beats, for example, if you notice it beating faster
• pseudotumour cerebri (benign intracranial hypertension) which can lead to blindness
• These are all serious side effects. You may need urgent medical attention. Tell your doctor if you notice any of the following: The following side effects have been reported less frequently:
• hyperthyroidism (condition in which your thyroid produces too much thyroid hormone)
• hypothyroidism (condition in which your thyroid produces too little thyroid hormone). The following side effects have been reported with a unknown frequency:
• eosinophilia (an increase in the number of white blood cells in response to some medicines), fever, liver problems
• unable to tolerate heat, flushing
• increased appetite
• excitability, restlessness, confusion, agitation (irritation), insomnia (inability to sleep)
• headache, tremors (involuntary movement of body parts), cephalagia (pain in head)
• increased blood pressure
• stomach cramps, nausea, vomiting, diarrhoea
• sweating, hair loss
• muscle cramps, muscle weakness, decrease in bone density
• menstrual irregularity (irregular menstrual periods), impaired fertility (problems conceiving), fatigue (tiredness), excessive loss of weight (a lot of weight loss)
• deformity of the skull in infants caused by the early closure of joints in the skull bone (craniostenosis)
• growth in children may slow or stop due to changes in bone growth
• intolerance to heat, temporary hair loss in children

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 levothyroxine or any of the other ingredients of MITHYRO (listed in section 6)
• If you have untreated hyperthyroidism, a disease in which the thyroid gland is overactive and produces too much thyroxine (this can lead to a life- threatening condition known as a thyroid storm where your heart rate, blood pressure, and body temperature can soar to dangerously high levels)
• If you have untreated adrenal insufficiency (condition where your adrenal gland does not produce enough steroid hormones), untreated pituitary insufficiency (decreased secretion of hormones produced by the pituitary gland)
• Treatment with MITHYRO must not be given to you if you have acute myocardial infarction (heart attack), acute myocarditis (inflammation of the heart muscle), acute pancarditis (inflammation of the heart or its surroundings). Do not take MITHYRO if any of the above applies to you. If you are not sure, talk to your doctor, nurse or pharmacist before you take MITHYRO

Use with care, and tell your doctor, if

• If you have anginal pain (pain in the heart area), palpitations and cramps in the muscle when you start your therapy with MITHYRO
• Before starting with MITHYRO make sure to tell your doctor if you have any heart disease, pituitary (gland in the brain) or other thyroid disease. Thus, frequent thyroid checks should be done
• If you are in menopause (when your menstrual period stops later in your life (for females))
• If you start to have fits, abnormal heartbeat, heart failure as these are signs of a “thyroid storm”
• If you have panhypopituitarism (disease of the pituitary gland), notify your doctor if you have this disease
• If you develop bone loss due to subclinical hyperthyroidism (low levels of the hormone TSH and normal level of the hormones T3 and T4), your doctor will give you the lowest possible dose of MITHYRO
• If your child is using MITHYRO, as the dosages must be monitored by your child’s doctor. Parents of children receiving MITHYRO should be aware that partial hair loss can occur during the first few months of therapy but their hair may grow back
• If you are elderly
• If you suffer from heart problems
• If you suffer from diabetes (high blood sugar levels)
• If you are taking medicines for diabetes (high blood sugar levels)
• If you have a history of epilepsy. Blood pressure will be regularly monitored when MITHYRO treatment is started in very low birth weight preterm neonates because rapid fall in blood pressure (known as circulatory collapse) may occur

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 healthcare provider for advice before taking MITHYRO

Interactions and medicines to check

The approved leaflet names these interactions.

• Warfarin: blood thinning medicine
• Anticonvulsants such as phenytoin and carbamazepine: medicine used to treat epilepsy
• Digoxin: medicine used to treat heart problems
• Sympathomimetics: examples are epinephrine (adrenaline), norepinephrine (noradrenaline) and dopamine
• Cholestyramine: medicine used to lower blood cholesterol levels
• Antacids such as cimetidine: medicine used to treat high acid levels
• Proton pump inhibitors such as omeprazole: medicine used to treat ulcers
• Bile acid sequestrants such as colestipol: medicine used to lower blood cholesterol levels
• Cation exchange resins such as kayexalate: medicine used to treat high blood levels of potassium
• Sucralfate: medicine used to treat stomach ulcers
• Calcium carbonate and ferrous sulphate: medicines used as supplements
• Oestrogen: medicine that imitates the effect of oestrogen in the body
• Tamoxifen: used to prevent some types of breast cancer
• Oral contraceptives: medicines used to prevent pregnancy
• Clofibrate: medicine used to lower blood cholesterol levels
• Methadone: medicine used as a cough suppressant
• 5-fluorouracil: medicine used to treat certain cancers
• Imatinib: medicine used to treat certain types of leukaemia
• Anabolic steroids: medicine that has similar effects as testosterone
• Amiodarone: medicine used to treat heart rhythm problems
• Antibacterials such as rifampicin and ciprofloxacin: medicine used to treat bacterial infections
• Antidiabetics such as metformin, glipizide: medicine used to treat high blood sugar levels
• Lithium: medicine used to treat mood disorders
• Antivirals such as ritonavir: medicine used to treat viral infections
• Beta-blockers such as propranolol: medicine used to treat high blood pressure
• General anaesthetics such as ketamine: medicine used to make you sleep before an operation
• Antimalarials such as chloroquine: medicine used to prevent malaria
• NSAIDs such as ibuprofen: medicines used to treat pain and inflammation
• Soya-based infant formula: used to feed infants
• Simvastatin: medicine used to lower high cholesterol levels
• Orlistat: some medicine used to treat obesity

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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