Overview
Levothyroxine is a prescription medication used to treat underactive thyroid (hypothyroidism) by replacing the hormone thyroxine. It requires careful dosage management, regular monitoring, and attention to potential interactions and side effects, especially during pregnancy.
About Levothyroxine and Its Use
- Levothyroxine replaces missing thyroxine hormone in patients with hypothyroidism.
- It is available as tablets or oral liquid, taken once daily in the morning.
- Treatment is generally lifelong and must not be stopped without medical advice.
Dosage and Administration
- Doses are individualized based on age, symptoms, hormone levels, and comorbidities.
- Tablets should be taken whole with water, at least 30 minutes before breakfast or caffeinated drinks.
- Missing doses should be skipped if too close to the next one—never double up.
Monitoring and Adjustments
- Blood tests are done before starting and regularly during treatment to adjust dosage.
- Frequent testing is required during pregnancy, medication changes, or if symptoms suggest dose issues.
Side Effects and Safety
- Most side effects result from taking too high a dose and may include nausea, vomiting, headaches, diarrhea, restlessness, flushing, sweating, muscle cramps, and shaking.
- Serious risks include heart palpitations, chest pain, and rare allergic reactions requiring immediate medical attention.
- Reporting side effects via the Yellow Card scheme is encouraged.
Special Considerations
- Safe in pregnancy and breastfeeding, but regular blood monitoring is needed and dose adjustments may be required.
- Inform your doctor if you have heart disease, diabetes, or adrenal problems before starting.
- Some medications and supplements, including iron, calcium, antacids, and certain epilepsy drugs, can interact with levothyroxine.
Interactions with Food, Drink, and Other Medications
- Caffeinated drinks and calcium-rich foods can reduce absorption; maintain timing gaps as recommended.
- Avoid kelp supplements and discuss biotin use with your doctor.
- Soya can interfere with levothyroxine effectiveness, possibly requiring extra blood tests.
Common Questions and Additional Information
- Levothyroxine does not typically affect fertility or driving ability.
- Alcohol is permitted but may worsen some side effects.
- Hair loss is related to hypothyroidism, not the medication itself—hair regrowth can take several months after treatment is established.
- Patients with hypothyroidism are entitled to free prescriptions in the UK with a medical exemption certificate.