Metyrapone is an inhibitor of adrenal steroid synthesis, primarily used in conjunction with other diagnostic tests to identify adrenal cortex insufficiency in adult and pediatric patients. Its pharmacological mechanism involves blocking the 11-β-hydroxylation reaction in the adrenal cortex, thereby reducing the synthesis of cortisol and corticosterone.

What Are the Side Effects of Metyrapone?

Common Side Effects

Cardiovascular system: Hypotension, which may occur after the use of metyrapone, leading to a drop in blood pressure.

Digestive system: Nausea, vomiting, abdominal discomfort or pain are relatively common gastrointestinal manifestations of this medication.

Central nervous system: Headache, dizziness, and sedation may affect the patient’s cognitive and motor abilities.

Skin system: Allergic reactions such as skin rashes.

Hematological system: Rare but possible reactions include leukopenia, anemia, and/or thrombocytopenia.

Severe Side Effects of Metyrapone

Acute Adrenal Cortex Insufficiency

This is one of the most serious risks.

Especially in patients with pre-existing partial hyposecretion or panhypopituitarism, there is a potential risk of developing acute adrenal cortex insufficiency after medication administration.

Close observation is required for the following symptoms: severe or persistent nausea and vomiting, abdominal pain, severe hypotension, weakness, or disturbance of consciousness.

Once clinical manifestations suggestive of adrenal insufficiency appear, the medication must be discontinued immediately. As soon as possible, glucocorticoid replacement therapy and supportive treatments such as fluid replacement should be administered.

Drug Overdose Reactions

In addition to causing adrenal cortex hypofunction, drug overdose may also induce arrhythmia, dehydration, and severe electrolyte disturbances.

In such cases, activated charcoal should be administered orally promptly (if the overdose is detected within 1 hour of medication intake). Additionally, intravenous infusion of hydrocortisone, normal saline, and glucose should be initiated as soon as possible to stabilize vital signs.

Precautions for Metyrapone

Contraindications

Contraindicated in patients with adrenal cortex insufficiency.

Contraindicated in patients with hypersensitivity to this product or any of its excipients.

Administration Method

This product is available in capsule form. The recommended single dose is 30 mg/kg (with a maximum dose not exceeding 3 grams), to be taken at midnight together with milk, yogurt, or snacks to reduce gastrointestinal irritation.

To prevent the occurrence of acute adrenal cortex insufficiency in certain high-risk patients, glucocorticoids may be administered as appropriate after blood collection for prevention.

When used in pediatric populations, testing must be performed under the close supervision and guidance of a physician. Dosages should be strictly controlled, and individualized administration based on body weight is required.