Elderly people are at high risk of pulmonary embolism and often have a combination of chronic diseases such as hypertension, diabetes, and coronary heart disease. However, after having a pulmonary embolism, many medications can interact with warfarin, and special caution is needed when taking the medication. This drug makes the INR go up? That drug makes the INR go down? But these are all drugs that must be taken to cure the disease, and it is not possible to stop any of them, so how should I take them? First point: read the instructions. Any kind of drug will come with instructions. Before taking it, you must carefully look at whether it interacts with anticoagulants (warfarin), and if so, you need to ask your primary care physician before eating it, weighing the pros and cons to see whether to adjust the dose or switch to a different drug. If it is not written, the patient can take it without worry. In the absence of instructions, you can check the Internet or put it aside for a while and come to the hospital to ask your primary care doctor, do not take the medicine blindly by yourself. Many patients think that a cold is a small thing, take some antibiotics, reduce inflammation, it does not bother, who know that when the INR review was shocked. Antibiotics can also affect the anticoagulant effect. Below I will list the common drugs that affect the efficacy of warfarin, so that patients can have some idea when they are taking multiple drugs. The drugs that enhance the anticoagulant effect of warfarin Antibiotics: 1, cephalosporin antibiotics; 2, macrolide antibiotics (erythromycin, roxithromycin, azithromycin, clarithromycin, etc.); 3, quinolone antibiotics, which are commonly used xx fascias. Antifungal drugs: azoles such as fluconazole, itraconazole, etc. The interaction of these drugs with warfarin can cause serious bleeding. Antacids commonly taken by patients with stomach acid: cimetidine, ranitidine, omeprazole, etc.; Common anti-arrhythmic drugs: amiodarone, propafenone, quinidine, propyzamide, etc.; Aspirin, clopidogrel, ibuprofen, etc. Some herbs that activate blood circulation and remove blood stasis can also enhance the effect of warfarin. Drugs that reduce the effect of warfarin Drugs of the vitamin K class, sodium phenytoin, barbiturates (phenobarbital, etc.), carbamazepine, paracetamol, corticosteroid inhibitors (amiloride, mitotane, bosentan), glucocorticoids, estrogens, oral contraceptives, rifampin, rifapentine, spironolactone, chlorothiazide, etc. How can you remember so many medications? So it is better to consult your doctor carefully and elaborate your disease situation truthfully, so that your doctor can understand your medication and help you use it reasonably.