Is marijuana effective for pain management?

Medical Marijuana for Pain Management

Medical cannabis may be considered as an adjuvant therapy for chronic pain management after conventional treatments have failed, but should not be used as first-line therapy due to limited evidence of efficacy and potential risks. 1

Evidence-Based Recommendations for Cannabis Use in Pain Management

Current Clinical Guidelines Position

• Cancer-Related Pain: The American Society of Clinical Oncology states that clinicians may follow specific state regulations allowing access to medical cannabis for patients with chronic pain after considering potential benefits and risks. However, there is insufficient evidence to recommend cannabis as first-line management. 1

• HIV-Associated Neuropathic Pain: Medical cannabis may be effective in appropriate patients with HIV-associated neuropathic pain, with a weak recommendation based on moderate-quality evidence. 1

• General Chronic Pain: Cannabis offers modest analgesia with minimal mild adverse effects. Evidence suggests it may be more effective for patients with a history of prior cannabis use. 1, 2

Specific Pain Conditions Where Cannabis May Be Beneficial

1. Neuropathic Pain: Low-strength evidence supports cannabis for alleviating neuropathic pain 3, 4

   • Cannabis-based medicines may increase the number of people achieving 50% or greater pain relief compared to placebo (21% vs 17%)
   • More effective for pain relief of 30% or greater (39% vs 33%)

2. Multiple Sclerosis-Related Pain: Modest evidence supports use 2

3. Cancer Pain: May be useful as adjuvant therapy 2

Practical Considerations for Clinical Use

Patient Selection

• Consider cannabis only after failure of conventional treatments:

  • NSAIDs
  • Acetaminophen
  • Adjuvant analgesics (gabapentin, pregabalin, duloxetine)
  • Topical analgesics 1

• Contraindications:

  • History of psychosis
  • Preexisting severe lung disease
  • Cannabis use disorder
  • Pregnancy 1

Risks and Adverse Effects

• Common adverse effects:

  • Nervous system disorders (61% vs 29% with placebo) 3
  • Psychiatric disorders (17% vs 5% with placebo) 3
  • Somnolence, sedation, amnesia, euphoric mood 1, 2
  • Hyperhidrosis, paranoia, confusion 2

• Serious concerns:

  • Increased risk for motor vehicle accidents 4
  • Psychotic symptoms 4
  • Short-term cognitive impairment 4
  • Potential for cannabis use disorder 1, 5

• Withdrawal rates:

  • 10% of participants withdrew from studies due to adverse events with cannabis-based medicines versus 5% with placebo 3

Formulations and Administration

• No particular preparation of cannabis has been proven superior to others 1
• The FDA has not approved any drug product containing or derived from botanical marijuana 1
• An 8% dermal patch or cream of capsaicin can provide pain relief for at least 12 weeks in HIV-associated peripheral neuropathic pain 1

Clinical Decision Algorithm

1. First-line treatments (try these before considering cannabis):

   • Gabapentin for neuropathic pain
   • NSAIDs/acetaminophen for inflammatory pain
   • Topical analgesics for localized pain
   • Non-pharmacological approaches (physical therapy, CBT)

2. If inadequate response to first-line treatments:

   • Consider adjuvant medications (SNRIs, TCAs)
   • Consider referral to pain specialist

3. If still inadequate pain control:

   • Evaluate patient for cannabis therapy risks:
     • History of substance use disorder?
     • Psychiatric comorbidities?
     • Cardiovascular or respiratory disease?
     • Operating heavy machinery/driving requirements?

4. If appropriate candidate for cannabis:

   • Follow state regulations
   • Start with low THC/high CBD formulations
   • Monitor for efficacy and adverse effects
   • Reassess regularly for continued benefit and development of adverse effects

Important Caveats

• The potential benefits of cannabis-based medicine might be outweighed by potential harms 3
• There is no strong evidence to recommend cannabis to decrease opioid use in patients with chronic pain 2
• Long-term risks have not been systematically analyzed 3
• The quality of evidence for pain relief outcomes is limited by exclusion of participants with history of substance abuse and other significant comorbidities from studies 3
• Cannabis may be associated with higher risk for behavioral health issues, including anxiety and depression, particularly in older adults 5