How Long Does Detox Take for Fentanyl or Methadone?

Fentanyl and methadone are both potent opioids, but they affect the body in different ways, which leads to distinct detox experiences. Fentanyl is a potent, often short-acting synthetic opioid. Methadone is a long-acting opioid often used to treat heroin or other opioid addictions. Both can cause physical dependence, so withdrawal from either one calls for medical supervision.

Attempting to detox at home can be both difficult and dangerous. The intensity of withdrawal symptoms often leads to a quick relapse, which can be life-threatening because tolerance crashes soon after quitting. If someone may be overdosing, call 911. If you or someone you know is thinking about suicide or self-harm, call or text 988.

Medical detox is a structured setting where nurses monitor withdrawal symptoms, the team responds to complications, and care is adjusted to the person’s condition and treatment plan.

Fentanyl is known for its rapid onset and short half-life, so its effects are felt quickly and leave the body relatively fast. That means withdrawal begins sooner and can be intense, with early symptoms often appearing in the first 6 to 12 hours after the last use. Typical timelines vary from person to person. How long a person stays in medical detox is determined by medical necessity, not a fixed schedule.

First 6–12 hours:

Early flu-like symptoms begin to appear. Your loved one may have muscle aches, anxiety, a runny nose, and be restless. They might feel irritable and have trouble sleeping.

Days 1–3 (peak symptoms):

Withdrawal symptoms typically peak during this time, though they may peak between days three and five. This is the most challenging phase. Symptoms can include severe muscle and bone pain, abdominal cramps, nausea, vomiting, and diarrhea. Intense cravings, anxiety, and depression are also common.

Days 4–7:

The most severe physical symptoms usually start to subside. Your loved one will likely still feel physically weak and emotionally drained. Cravings and mood swings can persist.

After week 1:

While the acute physical symptoms have passed, psychological symptoms can linger. This is known as post-acute withdrawal syndrome (PAWS), which can include anxiety, depression, insomnia, and mood swings for several weeks or months.

Why isn't the timeline more predictable?

The exact timeline can vary based on factors like the type of fentanyl used, the duration of use, the amount used, and the person's overall health. Short-acting but potent fentanyl will have a different withdrawal pattern than extended-release fentanyl. Co-occurring mental or physical health issues can also prolong withdrawal symptoms. How long a full medical detox takes is determined by medical necessity and reviewed throughout the person's care.

Medical detox at Sheridan Grove Recovery in Aurora, CO, is medically supervised withdrawal management. Here is what the team does.

• 24/7 nursing support: Nurses monitor vital signs and withdrawal symptoms and respond if complications arise.
• Medication-assisted treatment (MAT): Licensed prescribers can prescribe medications like buprenorphine (Subutex) to ease withdrawal symptoms and reduce cravings.
• Hydration and meals: Dehydration and poor appetite are common during withdrawal. Nurses watch for dehydration, and meals are provided throughout the stay.
• A bridge to ongoing treatment: Detox is the first step. We prepare each person for the next phase of care, such as residential treatment, where they can address the underlying causes of addiction.

We know that watching a loved one go through detox is difficult. Our medical team uses evidence-based protocols to manage withdrawal symptoms from fentanyl, methadone, and other substances with compassion and dignity. Medicaid, commercial insurance and private pay are accepted. Coverage check happens on the call. Admissions answers 24/7.