# Effect of Guanfacine on Opioid-induced Hyperalgesia (OIH) and Tolerance

> **NCT01681264** · PHASE4 · TERMINATED · sponsor: **Massachusetts General Hospital** · enrollment: 137 (actual)

## Conditions studied

- Chronic Pain

## Interventions

- **DRUG:** Morphine
- **DRUG:** Guanfacine 1mg
- **DRUG:** Guanfacine 2mg
- **DRUG:** Placebo

## Key facts

- **NCT ID:** NCT01681264
- **Lead sponsor:** Massachusetts General Hospital
- **Sponsor class:** OTHER
- **Phase:** PHASE4
- **Study type:** INTERVENTIONAL
- **Status:** TERMINATED
- **Start date:** 2014-09
- **Primary completion:** 2022-12
- **Final completion:** 2023-12
- **Target enrollment:** 137 (ACTUAL)
- **Why stopped:** End of NIH funding
- **Last updated:** 2026-04-24

## Collaborators

- [object Object]
- [object Object]

## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT01681264

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT01681264, "Effect of Guanfacine on Opioid-induced Hyperalgesia (OIH) and Tolerance". Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/clinical/NCT01681264. Licensed CC0.

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