Substance guides

Opioid withdrawal timeline: What to expect day by day

Published August 5, 2025 · 8 min read · Updated April 2026

Reviewed for accuracy by licensed clinical professionals.

Opioid withdrawal is intensely uncomfortable but rarely life-threatening. The timeline depends on whether you are withdrawing from short-acting (heroin, oxycodone) or long-acting (methadone, fentanyl) opioids.

Short-acting opioids (heroin, oxycodone)

Symptoms begin 8-12 hours after last dose. Muscle aches, anxiety, restlessness, runny nose, sweating. Peak at 36-72 hours with nausea, vomiting, diarrhea, abdominal cramping, dilated pupils, and rapid heartbeat. Physical symptoms largely resolve by days 5-7.

Long-acting opioids (methadone)

Symptoms begin 24-36 hours after last dose. Peak at days 3-5. May persist for 2-3 weeks due to slower clearance. Generally less intense but more prolonged than short-acting withdrawal.

Fentanyl complication

Street fentanyl accumulates in fat tissue and releases slowly, creating unpredictable withdrawal timing. Symptoms may begin, improve, then return as stored fentanyl releases. This complicates Suboxone induction and is why many clinicians now use micro-dosing protocols.

Post-acute withdrawal

After acute physical symptoms resolve, psychological symptoms persist for weeks to months: insomnia, anxiety, depression, irritability, difficulty concentrating, and reduced stress tolerance. This is when relapse risk is highest.

Authoritative sources

This article references guidelines from: NIDA · SAMHSA · CDC

Frequently asked questions

How long does opioid withdrawal last?

Acute physical symptoms: 5-7 days for short-acting opioids, 2-3 weeks for methadone. Post-acute symptoms may persist for months.

Can opioid withdrawal kill you?

Rarely directly fatal, but severe dehydration from vomiting and diarrhea can be dangerous. Medical supervision is recommended.

What helps with opioid withdrawal?

MAT (buprenorphine or methadone) eliminates withdrawal entirely. Comfort medications include clonidine, anti-nausea drugs, anti-diarrheal agents, and sleep aids.

Disclaimer: Informational only. Not medical advice. SAMHSA: 1-800-662-4357.