Clinical Update: "Treatment of Acute and Recurrent Idiopathic Pericarditis"  
Circ April 23 2013
http://circ.ahajournals.org/content/127/16/1723.full
"Summary

Appropriate therapy for acute idiopathic pericarditis is an NSAID for ≈2 weeks, and it is also reasonable to prescribe colchicine for up to 3 months (the duration used in clinical trials), especially to reduce the rate of recurrence. For initially refractory symptoms, the parenteral NSAID ketorolac may be beneficial. For recurrent episodes of pericarditis, treatment with an NSAID plus colchicine is recommended, but for a more prolonged course. During NSAID treatment, concurrent gastric protection therapy should be considered. Only for truly refractory cases should glucocorticoid therapy be used."