Single dose dipyrone for acute renal colic pain.

Renal colic pain is extremely painful and requires immediate treatment with strong analgesics. Dipyrone is the most popular non-opioid first line analgesic in many countries but in others it has been banned (e.g. USA, UK) because of its association with blood dyscrasias such as agranulocytosis. Since dipyrone is used in many countries (e.g. Brazil, Spain) there is a need to determine the benefits and harms of its use to treat renal colic pain.