Patient leaflets and SmPCs, drug interaction checker, official and paediatric dosages, pregnancy and breastfeeding guidance, and NHS pharmacy opening hours — all in one place.
Patient leaflets and SmPCs, drug interaction checker, official and paediatric dosages, pregnancy and breastfeeding guidance, and NHS pharmacy opening hours — all in one place.
Thyroxine is a hormone which is produced naturally in the body by the thyroid gland. Levothyroxine is a synthetic version of this hormone. Thyroxine controls how much energy your body uses. When the thyroid gland does not produce enough thyroxine (a condition known as hypothyroidism), many of the body's functions slow down. Some of the most common symptoms of hypothyroidism are: • tiredness • weight gain • feeling depressed Levothyroxine Aristo/Vencamil is used to replace the thyroxine that your thyroid gland cannot produce and prevent the symptoms of hypothyroidism. Before starting your treatment your doctor will carry out a blood test to work out how much levothyroxine you need.
If any of these apply to you, do not take this medicine and go back to your doctor to discuss your treatment. Warnings and precautions Talk to your doctor, pharmacist or nurse before taking Levothyroxine Aristo/Vencamil, • if you have suffered with an under active thyroid gland for a long time; • if you suffer from heart problems including angina, coronary artery disease or high blood pressure. The doctor may require an ECG before starting treatment with levothyroxine, as changes induced by hypothyroidism may be confused with evidence of ischaemia (decreased oxygen in a tissue); • if you have epilepsy (fits). Fits have been rarely reported when starting the treatment with levothyroxine; • if you have a particular hormonal disorder called panhypopituitarism; • if you are being treated for diabetes. The dose of your anti-diabetic medicine may need to be changed as levothyroxine can raise blood sugar levels; • if you are over 50 years of age. Subclinical hyperthyroidism (where the thyroid gland makes too much thyroxine) may occur if your dose is too high and this could be associated with bone loss (osteoporosis). This will usually disappear after reducing the dose or stopping the tablets. However, you must not change the dose or stop the tablets without talking to your doctor first. Patients occasionally find that they feel less well when changing from one levothyroxine medicine to another. You should tell your doctor if you get any side effects so that your blood can be checked for levels of thyroid hormone. If your symptoms persist you may need a specific brand of levothyroxine to be prescribed. Thyroid hormones are not suitable for weight reduction. Intake of thyroid hormones will not reduce your weight, if your thyroid hormone level is in a normal range. Serious or even life threatening side effects may occur if you increase the dose without special advice from your doctor, especially when taken together with other medicines for weight reduction. Blood tests Before you start taking levothyroxine your doctor will do a blood test to see how much thyroxine your thyroid gland is making and what dose of the medicine you will need. Once you start taking the medicine your doctor will want you to have regular blood tests to see how well the medicine is working. If you are about to undergo laboratory testing for monitoring your thyroid hormone levels, you must inform your doctor and/or the laboratory personnel that you are taking or have recently taken biotin (also known as vitamin H, vitamin B7 or vitamin B8). Biotin may affect results of your laboratory tests. Depending on the test, the results may be falsely high or falsely low due to biotin. Your doctor may ask you to stop taking biotin before performing laboratory tests. You should also be aware that other products that you may take, such as multivitamins or supplements for hair, skin, and nails could also contain biotin. This could affect the results of laboratory tests. Please inform your doctor and/or the laboratory personnel, if you are taking such products (Please note the information in section 'Other medicines and Levothyroxine Aristo/Vencamil'). Children Blood pressure will be regularly monitored when levothyroxine treatment is started in very low birth weight preterm neonates because a rapid fall in blood pressure (known as circulatory collapse) may occur. Children receiving thyroid agent may experience partial loss of hair during the first few months of therapy, but this effect is usually temporary and subsequent regrowth usually occurs.
Other medicines and Levothyroxine Aristo/Vencamil Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines. This includes over the counter medicines, herbal remedies and vitamin supplements. Many medicines affect the way levothyroxine works. The effects of other drugs may also be affected by levothyroxine. The following may affect the way that levothyroxine works: • medicines for epilepsy such as carbamazepine, phenytoin, primidone and barbiturates • products containing St. John's Wort (a herbal medicine) • sertraline – used to treat depression and anxiety disorders • antacids – used to treat indigestion • medicines containing calcium salts • cimetidine – used to reduce excess stomach acid • proton pump inhibitors (such as omeprazole, esomeprazole, pantoprazole, rabeprazole, and lansoprazole) are used to reduce the amount of acid produced by the stomach, which may reduce the absorption of levothyroxine from the intestine and thereby make it less effective. If you are taking levothyroxine while receiving treatment with proton pump inhibitors, your doctor should monitor your thyroid function and may have to adjust the dose of Levothyroxine Aristo/Vencamil • sucralfate – used to treat and prevent stomach and duodenal ulcers • cholestyramine and colestipol – used to treat high levels of fat in the blood • polystyrene sulphone resin – used to reduce high levels of potassium in the blood • medicines containing iron that are taken by mouth • rifampicin – used to treat infections • imatinib – used to treat certain types of cancer • beta blockers such as atenolol and sotalol – used to treat high blood pressure and heart problems • oestrogen containing medicines for hormone replacement therapy (HRT) and contraception ("the 'pill") • androgen containing medicines for male hormone replacement therapy • corticosteroids such as hydrocortisone and prednisolone – used to treat inflammation • amiodarone – used to treat an irregular heart beat • orlistat – used to treat obesity • ritonavir - used to control HIV and chronic hepatitis C virus • lovastatin – used to treat high cholesterol. The following may be affected by levothyroxine: • anticoagulant medicines to prevent blood clots such as warfarin • medicines to treat diabetes such as insulin and metformin • tricyclic antidepressants such as amitriptyline, imipramine and dosulepin • medicines that stimulate the sympathetic nervous system such as adrenaline (used to treat severe allergic reactions) or phenylephrine (a decongestant found in many cold and flu treatments) • digoxin – used to treat heart problems • anti-inflammatory medicines such as phenylbutazone or aspirin • propranolol – used to treat high blood pressure and heart problems • ketamine – used as an anaesthetic. If you need to have an operation, please tell your doctor or anaesthetist that you are taking levothyroxine. If you are taking or have recently taken biotin, you must inform your doctor and/or the laboratory personnel when you are about to undergo laboratory testing for monitoring your thyroid hormone levels. Biotin may affect results of your laboratory tests (see section 2 'warnings and precautions'). Pregnancy and breast-feeding If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine. Your doctor will decide if you should continue treatment with levothyroxine whilst you are pregnant, particularly in the first three months of your pregnancy.
Driving and using machines This medicine should not affect your ability to drive and use machines. Information on sodium content This medicine contains less than 1 mmol sodium (23 mg) per tablet, that is to say essentially 'sodiumfree'
If you take more Levothyroxine Aristo/Vencamil than you should If you (or someone else) swallow a lot of the tablets at the same time, or you think a child may have swallowed some, contact your nearest hospital casualty department or tell your doctor immediately. Signs of an overdose may include: fever, chest pain (angina), racing or irregular heartbeat, muscle cramps, headache, restlessness, flushing, sweating, diarrhoea, shaking (tremor), difficulty sleeping (insomnia) and very high temperature (hyperpyrexia). These signs can take up to 5 days to appear. Take any remaining tablets and this leaflet with you so that the medical staff know exactly what you have taken. If you forget to take Levothyroxine Aristo/Vencamil If you forget to take a dose, take it as soon as you remember unless it is nearly time for your next dose. Do not take a double dose to make up for a forgotten dose. If you forget to give your child their dose, contact your doctor or pharmacist for further advice. If you stop taking Levothyroxine Aristo/Vencamil These tablets are for long term use. You may need to take them for the rest of your life. Do not stop taking the tablets unless your doctor has told you to do so. If you have any further questions on the use of this medicine, ask your doctor or pharmacist.
Like all medicines, this medicine can cause side effects, although not everybody gets them. Stop taking the tablets and go to hospital at once if you have: • a rare allergic reaction such as swelling of the face, tongue, lips and throat, difficulty breathing, severe itching of your skin with raised lumps, joint pain, sensitivity to the sun, general feeling of being unwell. You may need urgent medical attention. Some patients may experience a severe reaction to high levels of thyroid hormone. This is called a "thyroid crisis" and you should contact your doctor immediately if you have any of the following symptoms: • very high temperature; fast heart rate; irregular heartbeat; low blood pressure; heart failure; jaundice; confusion; fits and coma. Tell your doctor or pharmacist if any of the following side effects continue, get worse or if you notice any other side effects not listed. Most of the side effects are similar to the symptoms of hyperthyroidism (where the thyroid gland makes too much thyroxine) and are due to your dose of the medicine being too high. They will usually disappear after reducing the dose or stopping the tablets. However, you must not change the dose or stop the tablets without talking to your doctor first. Not known (frequency cannot be estimated from the available data) • headache • flushing • high temperature, sweating • hair loss • weight loss • tremor, restlessness, excitability, difficulty sleeping (insomnia) • increased pressure around the brain in children that is not caused by a tumour or other diseases (benign intracranial hypertension) • chest pain (angina), pounding, irregular or fast heartbeat • diarrhoea, vomiting • muscle cramps, muscle weakness
• 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 • irregular periods • intolerance to heat and temporary hair loss in children. Reporting of side effects If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects you can help provide more information on the safety of this medicine.
Vencamil 12.5 microgram tablets comes as tablet containing 12.5 microgram. Always follow the dose your doctor or pharmacist has given you, and read the leaflet that comes with the medicine.
The active substance in Vencamil 12.5 microgram tablets is levothyroxine sodium anhydrous.
Medicines with the same active substance include: Vencamil 100 micrograms tablets, Vencamil 25 microgram tablets, Vencamil 50 microgram tablets, Vencamil 75 microgram tablets. They are interchangeable only if your prescriber or pharmacist says so.
This leaflet reproduces the patient information leaflet approved for Vencamil 12.5 microgram tablets, as published on the electronic medicines compendium (emc). The version printed inside your medicine’s packaging is the one that applies to you.
Whether a medicine is available over the counter or on prescription only depends on its licence. Check the leaflet, or ask your pharmacist — they can tell you straight away.
The text above reproduces the patient information leaflet approved for this medicine, restructured for easier reading.
Recommended clinical indications:
• control of hypothyroidism
• congenital hypothyroidism in infants
• acquired hypothyroidism in children
• juvenile myxoedema.
Posology
In younger patients and in the absence of heart disease, a serum Levothyroxine (T4) level of 70 to 160 nanomols per litre, or a serum thyrotropin level of less than 5 milli-units per litre should be targeted. A pre-therapy ECG is valuable because ECG changes due to hypothyroidism may be confused with ECG evidence of cardiac ischaemia. If too rapid an increase in metabolism is produced (causing diarrhoea, nervousness, rapid pulse, insomnia, tremors, and sometimes anginal pain where there is latent cardiac ischaemia,) dosage must be reduced, or withheld, for a day or two, and then re-started at a lower dose level.
Adults
Patients under 50 years of age:
Initially 100 micrograms daily, preferably taken before breakfast or the first meal of the day. Adjust at three to four week intervals by 50 micrograms until normal metabolism is steadily maintained. The final daily dose may be up to 100 to 200 micrograms.
Patients over 50 years of age:
a) Without cardiac disease: Initially, it is not advisable to exceed 50 micrograms daily. In this condition, the daily dose may be increased by 50 micrograms at intervals of every 3-4 weeks, until stable thyroxine levels are attained. The final daily dose may be up to 50 to 200 micrograms.
b) With cardiac disease: Where there is cardiac disease, 25 micrograms daily or 50 micrograms on alternate days is more suitable. In this condition, the daily dose may be increased by 25 micrograms at intervals of every 4 weeks, until stable thyroxine levels are attained. The final daily dose may be up to 50 to 200 micrograms.
For patients aged over 50 years, with or without cardiac disease, clinical response is probably a more acceptable criterion of dosage rather that serum levels.
Elderly
Dosage is the same as that for patients aged over 50 years.
Paediatric population
The maintenance dose is generally 100 to 150 micrograms per m² body surface area. The dose for children depends on their age, weight and the condition being treated. Regular monitoring using serum TSH levels, as in adults, is required to make sure he/she gets the right dose. Infants should be given the total daily dose at least half an hour before the first meal of the day.
Congenital hypothyroidism in infants
For neonates and infants with congenital hypothyroidism, where rapid replacement is important, the initial recommended dosage is 10 to 15 micrograms per kg BW per day for the first 3 months. Thereafter, the dose should be adjusted individually according to the clinical findings and thyroid hormone and TSH values.
Acquired hypothyroidism in children
For children with acquired hypothyroidism, the initial recommended dosage is 12.5- 50 micrograms per day. The dose should be increased gradually every 2 to 4 weeks according to the clinical findings and thyroid hormone and TSH values until the full replacement dose is reached.
Juvenile myxoedema in children
The initial recommended dosage is 25 micrograms daily. In such conditions, the daily dose may be increased by 25 micrograms at intervals of every 2 - 4 weeks, until mild symptoms of hyperthyroidism are seen. The dose will then be reduced slightly.
In children under 5 years of age, the administration of whole tablets is not recommended.
It is also recommended that tablets are not crushed and dispersed in water or other liquids owing to limited solubility, which could lead to dosing inaccuracy. In this age group, it is preferable to administer an approved oral solution of levothyroxine.
Method of administration
Oral.
• Hypersensitivity to the active substance or any of the excipients listed in section 6.1.
• Thyrotoxicosis
• Adrenal gland disorder or adrenal insufficiency
• Treatment with levothyroxine must not be initiated in acute myocardial infarction, acute myocarditis, and acute pancarditis.
• Combination therapy of hyperthyroidism with levothyroxine and anti-thyroid agents is not indicated in pregnancy (see section 4.6)
Interactions affecting other drugs
Levothyroxine increases the effect of anticoagulants (Warfarin) and it may be necessary to reduce the anticoagulation dosage if excessive, hypoprothrombinaemia and bleeding are to be avoided.
Blood sugar levels are raised and dosage of anti-diabetic agents may require adjustment.
Tricyclic anti-depressants (e.g. amitriptyline, imipramine, dosulepin) response may be accelerated because levothyroxine increases sensitivity to catecholamines; concomitant use may precipitate cardiac arrhythmias.
The effects of sympathomimetic agents (e.g. adrenaline or phenylephrine) are also enhanced.
Cardiac glycosides: If levothyroxine therapy is initiated in digitalised patients, the dose of digitalis may require adjustment. Hyperthyroid patients may need their digoxin dosage gradually increased as treatment proceeds because initially patients are relatively sensitive to digoxin.
NSAIDs: False low plasma concentrations have been observed with concurrent anti- inflammatory treatment such as phenylbutazone or acetylsalicylic acid and levothyroxine therapy.
Beta Blockers: levothyroxine (thyroxine) accelerates metabolism of propranolol, atenolol and sotalol.
General anaesthetics: Isolated reports of marked hypertension and tachycardia have been reported with concurrent ketamine administration.
Interactions affecting Levothyroxine
Amiodarone may inhibit the de-iodination of thyroxine to tri iodothyronine resulting in a decreased concentration of tri iodothyronine, thereby reducing the effects of thyroid hormones.
Anti-convulsants, such as carbamazepine and phenytoin, enhance the metabolism of thyroid hormones and may displace them from plasma proteins. Initiation or discontinuation of anti-convulsant therapy may alter levothyroxine dosage requirements.
Effects of levothyroxine may be decreased by concomitant sertraline.
Absorption of levothyroxine (thyroxine) possibly reduced by antacids, calcium salts, cimetidine, oral iron, sucralfate, colestipol, polystyrene sulphonate resin and cholestyramine (administration should be separated by 4-5 hours).
Proton pump inhibitors (PPIs): Co-administration with PPIs may cause a decrease in the absorption of the thyroid hormones, due to the increase of the intragastric pH caused by PPIs. Regular monitoring of thyroid function and clinical monitoring is recommended during concomitant treatment. It may be necessary to increase the dose of thyroid hormones. Care should also be taken when treatment with PPI ends.
Metabolism of levothyroxine (thyroxine) is accelerated by rifampicin, barbiturates, products containing St John's Wort (Hypericum perforatum L.) and primidone. Therefore, patients on thyroid replacement therapy may require an increase in their dose of thyroid hormone if these products are given concurrently.
Imatinib: plasma concentration of levothyroxine (thyroxine) possibly reduced by imatinib.
Beta blockers may decrease the peripheral conversion of levothyroxine to triiodothyronine.
Lipid regulating drugs: Lovastatin has been reported to cause one case each of hypothyroidism and hyperthyroidism in two patients taking levothyroxine.
Sex Hormones: Oestrogen, oestrogen containing product (including hormone replacement therapy) and oral contraceptives may increase the requirement of thyroid therapy dosage. Conversely, androgens and corticosteroids may decrease serum concentrations of Levothyroxine-binding globulins.
Anti-obesity drugs such as orlistat may decrease levothyroxine absorption which may result in hypothyroidism (monitor for changes in thyroid function).
A number of drugs may affect thyroid function tests and this should be borne in mind when monitoring a patient on levothyroxine therapy.
Post-marketing cases have been reported indicating a potential interaction between ritonavir containing products and levothyroxine. Thyroid- stimulating hormone (TSH) should be monitored in patients treated with levothyroxine at least the first month after starting and /or ending ritonavir treatment.
Interference with laboratory tests: Biotin may interfere with thyroid immunoassays that are based on a biotin/streptavidin interaction, leading to either falsely decreased or falsely increased test results (see section 4.4).
Pregnancy
The safety of Levothyroxine treatment during pregnancy is not known, but any possible risk of foetal abnormalities should be weighed against the risk to the foetus of untreated hypothyroidism.
Combination therapy of hyperthyroidism with levothyroxine and anti-thyroid agents is not indicated in pregnancy. Such combination would require higher doses of anti-thyroid agents, which are known to pass the placenta and to induce hypothyroidism in the infant.
Breast-feeding
Levothyroxine is excreted in breast milk in low concentrations, and it is contentious whether this can interfere with neonatal screening.
Fertility
No data are available.
Levothyroxine has no or negligible influence on the ability to drive and use machines.
Symptoms
In most cases there will be no features. Signs of an overdose may include: fever, chest pain (angina), racing or irregular heartbeat, muscle cramps, headache, restlessness, flushing, sweating, diarrhoea, tremor, insomnia and hyperpyrexia. These signs can take up to 5 days to appear. Atrial fibrillation may develop. Convulsions occurred in one child. There may be increased toxicity in those with pre-existing heart disease.
Management
Give oral activated charcoal if more than 10mg has been ingested by an adult or more than 5mg by a child, within 1 hour. If more than 10mg has been ingested by an adult or more than 5mg by a child, take blood 6-12 hours after ingestion for measurement of the free thyroxine concentration. The analysis does not need to be done urgently but can wait until the first working day after the incident. Patients with normal free thyroxine concentrations do not require follow up. Those with high concentrations should have outpatient review 3-6 days after ingestion to detect delayed onset hyperthyroidism. Features of clinical hyperthyroidism should be controlled with beta-blockers, e.g. propranolol.
Ask anything about Vencamil 12.5 microgram tablets. The assistant answers only from this leaflet — if the leaflet does not cover it, it will say so. It does not give medical advice.
Answers come from the patient leaflet published on the electronic medicines compendium (emc). They are not medical advice. Ask a pharmacist or your GP if you are unsure. For urgent help call NHS 111, or 999 in an emergency.
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