Once you have made it through Club Neon you will receive a phone call not to talk to the DJ Electrohead. You just have to pick any option but kill him, while speaking to Electrohead. After a little bit of a converstaion Elctrohead will be shot and killed. You will go home and rest. Then talk to the Doctor. Choose every option to not take the medication. When you leave the office without taking the medication you will unlock the Refused Medication achievement. Hope this helped!