My fiance is from Costa Rica.. I asked her and apparently as long as you arent near the border you shouldnt have many problems getting whatever you want.. At the border prices are jacked for everything.. No scrips at the pharmacies, but good luck getting them to understand you if you dont speak spanish..
Also, a little american $$ goes a long way in Costa Rica.. watch out tho, San Jose has a high percentage of people infected with STD's..