Methimazole
(Redirected from Tapazole)
| Drug monograph · NCLEX study reference | |
| Trade names | Tapazole |
|---|---|
| Therapeutic class | Antithyroid |
| Pharmacologic class | Thioamide |
| Onset / peak / duration | Effect over 1 to 3 weeks as stored hormone depletes. |
| Half-life / level | Half-life 4 to 6 hours; monitor thyroid labs. |
| Routes | PO (oral) |
| High-alert (ISMP) | No |
| Black box warning | None |
| Antidote / reversal | None; discontinue. |
| Pregnancy / lactation | Avoid in the first trimester; can be used later. |
Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.
Methimazole (brand name Tapazole) — Antithyroid; Thioamide.
Identification
- Therapeutic class: Antithyroid.
- Pharmacologic class: Thioamide.
Pharmacology
- Mechanism of action: Inhibits thyroid hormone synthesis by blocking iodine organification.
- Onset / peak / duration: Effect over 1 to 3 weeks as stored hormone depletes.
- Half-life / therapeutic level: Half-life 4 to 6 hours; monitor thyroid labs.
Clinical use
- Indications: Hyperthyroidism, Graves disease, preoperative preparation.
- Usual dose, route, frequency: 5 to 40 mg PO daily.
- Maximum dose / adjustments: Titrate to thyroid labs.
Safety
- Contraindications: First-trimester pregnancy (PTU preferred then), known agranulocytosis with thioamides.
- Black box warning: None.
- Interactions: Warfarin, digoxin, beta blockers, theophylline (levels change as thyroid status normalizes).
- Pregnancy / lactation: Avoid in the first trimester; can be used later.
- High-alert: No.
Adverse effects
- Common side effects: Rash, GI upset, arthralgia.
- Serious effects to report: Agranulocytosis (fever, sore throat), hepatotoxicity.
- Antidote / reversal: None; discontinue.
Nursing process
- Assessment before administration: Thyroid labs, baseline CBC and LFTs.
- Interventions during therapy: Teach to report fever or sore throat promptly.
- Monitor: Thyroid labs, CBC, LFTs.
- Evaluation / expected outcome: Normalized thyroid function.
Patient teaching
- Patient teaching: Report any sign of infection immediately.
- Notify provider if: Fever, sore throat, yellowing of skin, easy bruising.
- Administration tips: Consistent daily timing.