For educational use only. MedTime is not medical advice. Consult a licensed clinician or pharmacist before making medication decisions.

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Thyroid
Oral

Methimazole

Thionamide

Also sold as Tapazole

Onset of effect
1 day – 2 days
Felt/clinical effect
Tmax (peak blood level)
1 hr – 2 hr
Pharmacokinetic peak
Duration of effect
12 hr – 1 day
Per single dose

Cumulative therapeutic effect

Clinical euthyroidism typically reached over 4–8 weeks.

Effect timeline

Approximate single-dose timeline. Onset shows when effects are felt; Tmax shows when blood levels peak.

6 hr12 hr18 hr
Onset of effectTmax (peak blood level)Wears off

Notes

Hyperthyroidism; agranulocytosis warning.

What this is

Methimazole is a thionamide given by the oral route. It's typically used in the thyroid category.

What the numbers mean

After one oral dose you'd typically start noticing the effect in 1 day – 2 days. The drug reaches its highest blood level in about 1 hr – 2 hr, and a single dose usually keeps working for around 12 hr – 1 day.

Practical tips

Take consistently — the full benefit builds over time, not from a single dose. Swallow with water; check the label for food restrictions. Long-acting — take at roughly the same time each day for steady levels.

Important

Don't combine with other products in the same drug class without checking with a pharmacist. Stop and seek medical advice if you have an unexpected reaction, severe side effect, or symptoms that don't improve.

All timings are approximate population ranges for a typical adult dose. Individual response varies with age, genetics, formulation, food, and other medications.

Typical dosing

Source: OpenFDA drug label · adult dosing unless noted

Doses vary by age, weight, kidney/liver function, and indication. Don't change your dose without talking to your prescriber.

Verify on the exact label used:DailyMed search·OpenFDA record

Side effects & warnings

Source: OpenFDA drug label

Verify on the exact label used:DailyMed search·OpenFDA record

Educational information only — not medical advice. Times vary by person, dose, and formulation. Always consult a doctor or pharmacist for personal guidance.