What kind of medecine you have ? QuICK Cure ?
I would go with a good cleaning of gravel BEFORE starting the medecine. Furthermore, remove any active coal filter media from your filter. Then go with half dosage for 5 days, everyday. Remember DO NOT turn on the light of your tank during the treatment. Also, raise temp. to 86°F and if you have any means of improving the oxygenation of your water, do it as higher temp. reduces the amount of O2 disolved in water.
The above applies if your medecine contains Malachite Green and Formalin.
Good luck !
SB