Levothyroxine (Elderly)

How it works

It is converted to active triiodothyronine (T3) and restores physiological thyroid hormone levels, normalising metabolic rate and tissue function.

Prescribing in practice

• In older patients, and especially those with ischaemic heart disease, start at a low dose and titrate slowly, as rapid correction can precipitate angina, arrhythmia or myocardial ischaemia.
• Take on an empty stomach and apart from interacting agents such as calcium and iron salts, which impair absorption; consistent timing relative to food and other drugs is important.
• Over-replacement risks atrial fibrillation and accelerated bone loss, both of particular concern in older people.

Monitoring

Monitor thyroid function (TSH, with free T4) some weeks after initiation or dose changes and periodically thereafter, allowing time to reach steady state.

Counselling the patient

• Take at the same time each day, usually before food, and separately from calcium or iron supplements.
• Report palpitations, chest pain, tremor or unexpected weight change.
• Do not change the dose yourself; adjustments are guided by blood tests.

Evidence & guidelines

UK thyroid guidance recommends low starting doses and gradual titration of levothyroxine in older patients and those with cardiac disease to avoid precipitating ischaemic events.