Found this online, can't find anything about coral
Treats a wide variety of parasitic diseases including velvet, anchor worm, fish lice, hole-in-the-head disease (Hexamita spp. & Spironucleus spp.), gill & skin flukes (Dactylogyrus spp. & Gyrodactylus spp.). This medication will not color the aquarium water.
General Cure contains Praziquantel which is as safe in a reef tank as any medication, and Metronidazole which has activity against anaerobic bacteria. Neither of these chemicals will hurt the nitrifying bacteria that metabolize ammonia into nitrate, but it could suppress your denitrifying bacteria that break down nitrate. Why do you think that you need to use General Cure? It's best used for treating internal parasites, and the best way to use it for that is mixed into food.