What problems can occur in the combination of antihypertensive drugs? (1) The combination of antihypertensive drugs, calcium antagonists and ACEI can enhance the antihypertensive effect of most of them, but at the same time, the toxic side effects also increase. (2) The combination of felodipine and melotol may increase the blood concentration of the latter by 35%, which increases both efficacy and toxicity. (3) The combination of propranolol and nifedipine can enhance the antihypertensive effect, but be alert to hypotension and heart failure. (4) Calcium antagonists (such as slightly benzodipine, diltiazem) and day receptor blockers (such as metoprolol, atenolol) in combination, can occur cumulative synergistic therapeutic and toxic effects. (5) The combination of metoprolol and atenolol with verapamil can cause heart failure and conduction abnormalities. (6) The combination of verapamil and other antihypertensive drugs has synergistic effects, but the former dose should be adjusted. (7) Captopril combined with verapamil and atenolol, the former can reduce the pharmacological effect of the latter. (8) Central antihypertensive drugs (methyldopa, colistin) have synergistic effects when combined with other antihypertensive drugs. (9) Diuretics as basic hypotensive drugs used in combination with various antihypertensive drugs will play a role in reducing the dose of antihypertensive drugs and enhancing the antihypertensive effect, reducing adverse reactions. (10) When combined with sialogens, captive receptor blockers can increase plasma LDL, triglyceride and cholesterol. (11) Diuretics should not be used for hypertension combined with gout. (12) In cases of hypertension combined with renal impairment, the use of salivary voice and parotid precipitates is not recommended. (13) The combination of salivary voice and ginkgo preparation can increase blood pressure, but the mechanism is unknown. (14) Potassium-protecting diuretics (spironolactone, aminopterin) and ACEI, when used together, can increase potassium concentration and cause hyperkalemia, resulting in serious arrhythmias and even arrest. (15) The combination of diuretic and antihypertensive drugs such as pyridapamide, hydrochlorothiazide and ACEI is more likely to cause renal damage than using them alone.