**7. Main drugs implicated in reactions**

Drug classes most frequently associated with ADRs in both inpatients and outpatient populations are non steroidal anti-inflamatory drugs (NSAIDs), diuretic, anticoagulants, antiobiotics and antineoplastic agents.

Antibiotic and vaccination reactions are more frequent in the 0 –to-9 year age group.

In adults and elderly people, there a great variety of drugs causing adverse drug reactions. However, it depends the type of hospitalization, the deparment, etc, the type of adverse reactions and drugs implicated are quite different. Pimohamed et al. (2004) found that aspirin was the casual agent in 18% of cases of all admission for ADRs, while other NSAIDs and diuretics were implicates in 12% and 27% respectively. The most common ADRs of NSAIDs were GI bleeding, peptic ulcerations, haemorrhagic cerebrovascular accident, renal impairment, wheezing and rash. Grenouillet-Delacre et al. (2007) found that psychotropic drugs, immunosuppressive drugs, anticoagulants and antibiotics were more than 50% of life-threatening adverse drug reactions at admission to medical intensive care. In Spain, antibiotic and anticoagulants are the drugs more frequently implicated in ADRs appeared during hospitalization but in another epidemiologic study (Carrasco Garrido, 2010) found that main drugs implicated in admission into the hospital were antineoplastics and immunosuppressive therapy. However there are very few studies that show antineoplastics and immunosuppressive therapies as the cause of adverse drug reactions although they are being increasingly used and promote the appearance of infections, medullar aplasia, etc. Also cardiovascular drugs, mainly diuretics and hypotensors drugs account for some common ADRs.
