As an 11- β hydroxylase inhibitor, the side effects of metoprolol mainly involve endocrine disorders and gastrointestinal reactions, and in severe cases, may lead to adrenal cortex dysfunction. The following provides a detailed explanation from three aspects: common side effects, symptoms to be aware of, and special precautions.

Common tolerable side effects

1. Digestive system reactions

(1) The incidence of nausea and vomiting is about 30% -40%, mostly occurring in the early stages of medication; (2) Decreased appetite and abdominal discomfort often occur together; (3) Diarrhea is mostly mild and can be relieved by adjusting the medication time.

2. Symptoms of the nervous system

(1) The incidence of dizziness is about 15% -25%, which is related to orthostatic hypotension; (2) Headaches are often transient; (3) Symptoms of drowsiness suggest avoiding driving operations.

Serious side effects to be wary of

1. Adrenal cortex dysfunction

(1) Manifested as extreme fatigue and low blood pressure; (2) Possible occurrence of hyponatremia and hyperkalemia; (3) Regular monitoring of cortisol levels is required to adjust the dosage.

2. Allergic reactions

(1) Rash accompanied by itching; (2) Facial edema; (3) Severe cases may result in bronchospasm.

Special precautions

1. Drug interactions

(1) Combined use with antihypertensive drugs enhances the antihypertensive effect; (2) Alcohol exacerbates central inhibition; (3) Be alert to the effects of CYP3A4 inhibitors.

2. Monitoring requirements

(1) Evaluate adrenal function before treatment; (2) Regularly check electrolytes during medication; (3) If persistent vomiting occurs, seek medical attention immediately.