1. Acute poisoning includes palpitation, facial and neck muscle tremor, hand shaking and even inability to stand, dizziness and fatigue. Patients with original arrhythmia are more likely to react, such as tachycardia, premature ventricular contractions, ECG showing S-T segment depression and T wave inversion.

2. The above symptoms are more likely to occur in patients with hyperthyroidism, such as hypertension, coronary heart disease and hyperthyroidism.

3. Combined with glucocorticoid can cause hypokalemia, which leads to arrhythmia.

4. Repeated use will produce tolerance, weaken the effect on bronchiectasis and shorten the duration. Although the residual toxicity of clenbuterol is light, the FDA research shows that people who use sympathomimetic drugs or are allergic to prodrugs have more serious reactions to clenbuterol than normal healthy people.

The FDA is worried that illegal use of clenbuterol may lead to illness or death of workers who produce this drug. The FDA pointed out that the impact of occupational inhalation of clenbuterol on cardiovascular system may be more harmful than food intake, but it needs further confirmation.