Zithromax (Azithromycin) is an antibiotic very popular in primary care. E ‘widely used for a number of indications, as a community acquired respiratory tract infections and tonsillitis. I find it particularly useful because it is easy once daily dosing and short course of five days. Compliance patient has improved. Zithromax when it was first introduced and are educated me drugs, I noticed that there was a possibility of zithromax increase the effect of raising Coumadin and a patient of INR. For a couple of years, every patient I had to Coumadin had their INR’s been a couple of extra times during therapy with zithromax.

Once I did not find any significant changes in their INR. Because of cost and time, I stopped doing the extra work laboratory. I recently treated a male patient in his mid sixties with zithromax for the community has acquired bronchitis. He is to anticoagulant Coumadin for a mechanical aortic valve. For months, his INR was constant, without changes in the dosage of his Coumadin.

Two weeks after starting his zithromax, his respiratory symptoms had improved. He came to the office, however, for serious the left side and front of thigh pain. He requested urgent evaluation and possible hospitalization for a serious anaemia. His haemoglobin had fallen to 79. Addominale TAC has revealed a large retroperitoneal hematoma the left side. INR his admission was 15. He responded to transfusions and reversal of its anticoagulant with vitamin K. On the final review, zithromax would appear to be the culprit for the significant change in this INR patient and has made substantial bleed. We have examined other antibiotics commonly used to treat community acquired respiratory tract infection.

Many drug monographs state that no significant effects on the INR was observed clinically, but then give a disclaimer that patients should have their follow INR during therapy. From now on in my practice, every patient Coumadin requires that antibiotic therapy will have to put up with repeated checks INR. I am not going to risk the kind of reaction I’ve seen in this patient described.