Mixing drugs does not always produce stronger effects, but may bring risks due to interactions, such as reduced efficacy and increased toxicity. However, in certain cases, reasonable drug combinations can produce synergistic effects to enhance efficacy, such as: - **Combined use of antibiotics** - **β-lactams and aminoglycosides**: β-lactam antibiotics (such as penicillins and cephalosporins) inhibit bacterial cell wall synthesis, and aminoglycosides (such as gentamicin and streptomycin) hinder bacterial protein synthesis. The combination of the two has a synergistic bactericidal effect on a variety of Gram-positive and Gram-negative bacteria, and can be used to treat severe infections such as enterococcal endocarditis. - **Sulfonamides and trimethoprim**: Sulfonamides inhibit dihydrofolate synthase, and trimethoprim inhibits dihydrofolate reductase, which double blocks bacterial folate synthesis, enhances antibacterial effects by several to dozens of times, and reduces drug resistance. Commonly used to treat respiratory tract infections, urinary tract infections, etc. - **Combination of cardiovascular system drugs** - **Nitrates and beta-blockers**: Nitrates (such as nitroglycerin) dilate blood vessels and reduce cardiac preload, while beta-blockers (such as metoprolol) slow heart rate and reduce myocardial oxygen consumption. Combined use can enhance the anti-anginal effect and reduce the risk of myocardial infarction, and is often used to treat angina pectoris in coronary heart disease. - **Calcium channel blockers and beta-blockers**: Calcium channel blockers (such as amlodipine) inhibit calcium ion influx and dilate blood vessels, while beta-blockers inhibit cardiac beta receptors. The combination of the two can effectively control blood pressure, especially for hypertensive patients with a fast heart rate. - **Combination of anti-tuberculosis drugs** - **Isoniazid, rifampicin, pyrazinamide and ethambutol**: Isoniazid inhibits the synthesis of the cell wall of Mycobacterium tuberculosis, rifampicin inhibits RNA synthesis, pyrazinamide exerts an antibacterial effect in an acidic environment, and ethambutol inhibits bacterial protein synthesis. The combination of the four drugs is a common treatment for pulmonary tuberculosis, which can improve the cure rate and reduce the recurrence rate. The combination of drugs should be used with caution and should be decided by the doctor based on a comprehensive assessment of the patient's specific condition and physical condition, and the doctor should closely monitor the patient during the medication process to ensure safety and effectiveness.