Moderate to severe renal impairment (serum creatinine >160 micromol/L); suspected or confirmed cerebrovascular bleeding, hemorrhagic diatheses including coagulation disorders, complete or partial nasal polyps syndrome, angioedema or bronchospasm; hypovolemia, dehydration, history of asthma, patients under operation w/ high risk of hemorrhage haemostasis, on anticoagulant including low dose heparin (2,500-5,000 u 12 hrly); history of SJS or vesicular bullous rash. Neuraxial (epidural or intratechal) administration; prophylaxis before major surgery or intraoperatively when haemostasis is critical due to increased risk of bleeding. Pregnancy, labor, delivery or lactation. Childn <16 yr.