When a person does a detox from fentanyl at home by going cold turkey, they will experience intense withdrawal symptoms and cravings within about hours. At that point, if the person abusing fentanyl has easy access to the drug, they will likely relapse too quickly in the unpleasant withdrawal symptoms and drug cravings, the success rates with opioid addiction treatment using methadone or buprenorphine are much higher than quitting cold turkey still going through fentanyl withdrawal.