CBD prevented morphine-induced pain hypersensitivity and partially reduced withdrawal in rats

What the researchers found

In rats made physically dependent on morphine (10 days of twice-daily treatment), repeated CBD (30 mg/kg) prevented thermal hyperalgesia in both males and females. When withdrawal was induced with naloxone, morphine-dependent female rats predominantly showed rearing behavior while males showed teeth chattering. CBD treatment on day 11 partially attenuated withdrawal behavior in males, with milder effects in females (only in high withdrawal responders).

Why it matters

Opioid use disorder involves both tolerance-related hyperalgesia and withdrawal symptoms, and current treatments have significant limitations. Finding that CBD can prevent opioid-induced hyperalgesia while partially managing withdrawal symptoms opens a potential complementary treatment pathway.

The numbers in context

CBD 30 mg/kg; morphine 7.89 mg/kg twice daily for 10 days; naloxone 2 mg/kg for withdrawal; CBD prevented hyperalgesia in both sexes; partial withdrawal attenuation in males; females showed different predominant withdrawal behavior

How the study worked

Male and female rats underwent morphine-induced physical dependence protocol (7.89 mg/kg twice daily for 10 days). Nociception measured with hot plate test. Naloxone-precipitated withdrawal behavior scored after 11 days. CBD (30 mg/kg) tested for effects on both hyperalgesia and withdrawal.

What this study cannot tell us

Animal study that may not translate to human opioid dependence. Single CBD dose tested. Withdrawal attenuation was partial, not complete. Sex differences in response complicate translation. Naloxone-precipitated withdrawal differs from spontaneous withdrawal.

How to read the evidence

Well-controlled preclinical study with sex comparison provides preliminary mechanistic evidence, but animal model results require human validation.

When this study was published

2025 publication

The bigger picture

The opioid crisis demands alternatives for managing both pain and opioid side effects. These findings suggest CBD could complement opioid therapy by preventing the pain hypersensitivity that develops with chronic opioid use, potentially reducing the need for dose escalation.

Questions still open

• Would higher CBD doses produce more complete withdrawal attenuation? Why does CBD affect morphine-related outcomes differently in males versus females?

Common questions

Read the original research

Morphine-induced side effects can be differentially modulated by cannabidiol in male and female rats.

Behavioural pharmacology, 36(1), 1-15

Citation

Alves Jesus, Carlos Henrique; Volpe, Jaqueline; Sotomaior, Bruna Bittencourt; Barbosa, Maria Augusta Ruy; Ferreira, Matheus Vinicius; Fiatcoski, Fernanda; Genaro, Karina; de Souza Crippa, José Alexandre; Pires Souto, Dênio Emanuel; Maria da Cunha, Joice. (2025). Morphine-induced side effects can be differentially modulated by cannabidiol in male and female rats.. Behavioural pharmacology, 36(1), 1-15. https://doi.org/10.1097/FBP.0000000000000803

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