SciaticaEarly Phase 1NCT04982965
Brain Mechanisms Supporting Cannabis-induced Pain Relief
A Early Phase 1 study testing Active Cannabis in people with Sciatica and Lumbar Radiculopathy, run by University of California, San Diego at 1 site in United States.
Trial summary
Chronic low back pain is a common and disabling condition that affects millions of people in the United States. Many people with chronic low back pain do not get enough relief from current treatments. Read more about this study
- Who is it for?
- Ages 21 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Sciatica, Lumbar Radiculopathy, Lower Back Pain
- What is being tested?
- Active Cannabis
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 100 participants
- Where
- 1 siteUnited States
- Study dates
- 7 May 2021to 15 Mar 2027
- Phase
- Early Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 21 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Between 21-65 years old
- Currently 30 days cannabis free
- Lower back pain for three months or more
- Are not taking opioids
- If female and of a child bearing potential age, are not pregnant or nursing mothers
- Do not have mental or neurological conditions inhibiting sensory/motor functions
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- Do not have a lifetime history of dependence on cannabis
- Do not have a lifetime history of DSM-IV schizophrenia, bipolar disorder, panic disorder, or psychosis
- Prior THC-containing cannabis experience within the past two years
- Agrees not to use cannabis outside of the study during participation in the study
- Agrees not to use opioids or barbiturates during participation in the study
- Agrees not to drive a motor vehicle within 4 hours following last use of inhaled cannabis during participation in the study
Who cannot join
- Active pulmonary disease
- Allergy or past adverse effects or negative past experiences from cannabis
- Positive urine drug test for THC, barbiturates, opioids, oxycodone, or methadone
- Any significant illness, including cardiovascular disease, diabetes, renal and liver disease.
- Any current or history of an immunocompromising disease or condition (such as lupus, psoriasis, multiple sclerosis, etc.)
- Any current or history of neurologic conditions, including Parkinson disease, dementia, cognitive impairment, history of seizure disorder, and history of traumatic brain injury/head injury
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- Any current major psychiatric illness, such as bipolar disorder, major depression, psychosis, substance use disorder, or schizophrenia
- Any current or history of suicidal ideation or attempt
- Overt sensitivity to thermal stimulation
- Resting blood pressure > 140/90
- Resting heart rate > 100 beats/minute
- Prisoner
- Institutionalized
- Claustrophobia
- MRI contraindications
- Participation in any new (within 2 weeks prior or any time after enrollment) pain management procedures during the study period
- Known history of vasovagal fainting, syncope, or severe adverse reactions associated with blood draws or needle procedures
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Center for Functional MRI - W.M.Keck Building
La Jolla, California, 92093
Madelynn Meredith, BS, 619-431-1850, mameredith@health.ucsd.edu
Yasmeen Esshaki, MA, 619-786-0375, yesshaki@health.ucsd.edu
About this study
Chronic low back pain is a common and disabling condition that affects millions of people in the United States. Many people with chronic low back pain do not get enough relief from current treatments. Cannabis may help reduce pain, but researchers do not fully understand how it affects the brain in people with chronic pain. The purpose of this study is to examine how inhaled cannabis changes brain activity and reduces pain in people with chronic low back pain. Results from this study may help researchers better understand how cannabis works for pain and support the development of improved pain treatments.
Read the detailed description
Chronic low back pain is one of the most common causes of pain and disability in adults. Unfortunately, treatments that can directly reduce chronic low back pain remain limited. Cannabis has shown promise for pain relief, but researchers do not yet fully understand how it affects the brain or reduces pain in people with chronic pain.
The purpose of this study is to examine how inhaled (vaporized, not smoked) cannabis affects pain responses and brain activity in adults with chronic low back pain. Researchers will compare the effects of cannabis containing tetrahydrocannabinol (THC) to a placebo cannabis containing 0% THC.
This study involves one visit to the Keck Center for Functional MRI at UC San Diego. Participants will complete screening procedures, questionnaires, and pain testing using heat stimulation applied to the calf. Participants will be trained to rate their pain intensity and unpleasantness. A straight leg raise maneuver will also be performed to assess low back pain and any pain radiating down the leg.
Participants will inhale either THC-containing cannabis or placebo cannabis (no THC) using a vaporization device under study staff supervision. Brain imaging, heat pain testing, leg raise assessments, and pain ratings will be collected before and after cannabis administration to evaluate changes in pain processing and brain activity. Researchers will also assess self-reported pain, mood, sleep, stress, and cannabis-related effects using standardized questionnaires.
This study may improve understanding of how cannabis influences the brain and pain systems in people with chronic low back pain, and findings may help support the development of improved treatments for chronic pain.
- Conditions
- Sciatica, Lumbar Radiculopathy, Lower Back Pain, Degenerative Disc Disease, Chronic Low-back Pain (cLBP), Chronic Low Back and Leg Pain
- Being tested
- Active Cannabis, Placebo Cannabis
- Keywords
- Cannabis, Vaporized cannabis, THC, chronic low back pain
- Medical subject headings
- Sciatica, Radiculopathy, Low Back Pain, Intervertebral Disc Degeneration, Back Pain, Marijuana Abuse
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Active CannabisDrug
400 mg of vaporized and inhaled active cannabis (5.1%)
Placebo CannabisDrug
Also called Non-Active cannabis
400 mg of vaporized and inhaled placebo cannabis (<.1%)
| Study group | Role | What they receive |
|---|---|---|
| Active THC | Experimental | Participants will be administered 400mg of vaporized cannabis (5.1%) before pain testing and fMRI. Receives: Drug: Active Cannabis |
| Placebo THC | Placebo comparator | Participants will be administered 400mg of vaporized cannabis (<.1%) before pain testing and fMRI. Receives: Drug: Placebo Cannabis |
What is being measured
The primary outcome is the main question the study is designed to answer.
Cerebral Blood Flow (CBF)
Changes in brain blood flow and oxygen levels will be measured using non-invasive MRI-based brain imaging methods. These scans will assess how much blood is reaching brain tissue and how oxygen levels in the brain change over time.
Measured: All data will be collected at the single study session (Day 1).
Secondary outcomes (1)
Pain Ratings
Pain ratings will be assessed in response to noxious heat stimulation. Pain intensity and pain unpleasantness will be measured using a 0-10 Visual Analog Scale (VAS), where 0 indicates "no pain" and 10 indicates "most intense imaginable pain" or "most unpleasant imaginable pain." Higher scores indicate greater pain intensity or unpleasantness. Subjective response to cannabis will be assessed using a 0-10 Numeric Rating Scale (NRS), with higher scores indicating greater subjective effects.
Measured: All data will be collected at the single study session (Day 1).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Jul 2021
- Study start7 May 2021
- Primary completion15 Jan 2027 (estimated)
- Study completion15 Mar 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for SciaticaStudies of the same condition, open and under way.
- More trials run by University of California, San DiegoThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, San Diego
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Fadel Zeidan, University of California, San Diego
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04982965
- Sponsor's protocol ID
- 200011
- Status last verified
- Jan 2026
- First submitted
- 7 Jul 2021
- Last updated
- 3 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Brain Mechanisms Supporting Cannabis-induced Pain Relief
- ClinicalTrials.gov ID
- NCT04982965
- Acronym / sponsor ID
- 200011
- Conditions
- Sciatica, Lumbar Radiculopathy, Lower Back Pain, Degenerative Disc Disease, Chronic Low-back Pain (cLBP), Chronic Low Back and Leg Pain
- Keywords
- Cannabis, Vaporized cannabis, THC, chronic low back pain
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- University of California, San DiegoUniversity, hospital or other
- Study start
- 7 May 2021 (actual)
- Primary completion
- 15 Jan 2027 (estimated)
- Study completion
- 15 Mar 2027 (estimated)
- First posted
- 29 Jul 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Chronic low back pain is a common and disabling condition that affects millions of people in the United States. Many people with chronic low back pain do not get enough relief from current treatments. Cannabis may help reduce pain, but researchers do not fully understand how it affects the brain in people with chronic pain. The purpose of this study is to examine how inhaled cannabis changes brain activity and reduces pain in people with chronic low back pain. Results from this study may help researchers better understand how cannabis works for pain and support the development of improved pain treatments.
Detailed description
Chronic low back pain is one of the most common causes of pain and disability in adults. Unfortunately, treatments that can directly reduce chronic low back pain remain limited. Cannabis has shown promise for pain relief, but researchers do not yet fully understand how it affects the brain or reduces pain in people with chronic pain.
The purpose of this study is to examine how inhaled (vaporized, not smoked) cannabis affects pain responses and brain activity in adults with chronic low back pain. Researchers will compare the effects of cannabis containing tetrahydrocannabinol (THC) to a placebo cannabis containing 0% THC.
This study involves one visit to the Keck Center for Functional MRI at UC San Diego. Participants will complete screening procedures, questionnaires, and pain testing using heat stimulation applied to the calf. Participants will be trained to rate their pain intensity and unpleasantness. A straight leg raise maneuver will also be performed to assess low back pain and any pain radiating down the leg.
Participants will inhale either THC-containing cannabis or placebo cannabis (no THC) using a vaporization device under study staff supervision. Brain imaging, heat pain testing, leg raise assessments, and pain ratings will be collected before and after cannabis administration to evaluate changes in pain processing and brain activity. Researchers will also assess self-reported pain, mood, sleep, stress, and cannabis-related effects using standardized questionnaires.
This study may improve understanding of how cannabis influences the brain and pain systems in people with chronic low back pain, and findings may help support the development of improved treatments for chronic pain.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Active THC | Experimental | Drug: Active CannabisParticipants will be administered 400mg of vaporized cannabis (5.1%) before pain testing and fMRI. |
| Placebo THC | Placebo comparator | Drug: Placebo CannabisParticipants will be administered 400mg of vaporized cannabis (<.1%) before pain testing and fMRI. |
Who may qualify
- Ages
- 21 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (12 listed)
- Between 21-65 years old
- Currently 30 days cannabis free
- Lower back pain for three months or more
- Are not taking opioids
- If female and of a child bearing potential age, are not pregnant or nursing mothers
Key exclusion criteria (17 listed)
- Active pulmonary disease
- Allergy or past adverse effects or negative past experiences from cannabis
- Positive urine drug test for THC, barbiturates, opioids, oxycodone, or methadone
- Any significant illness, including cardiovascular disease, diabetes, renal and liver disease.
- Any current or history of an immunocompromising disease or condition (such as lupus, psoriasis, multiple sclerosis, etc.)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Active Cannabis400 mg of vaporized and inhaled active cannabis (5.1%) | Drug | Active THC |
| Placebo CannabisAlso: Non-Active cannabis400 mg of vaporized and inhaled placebo cannabis (<.1%) | Drug | Placebo THC |
Primary outcome
Cerebral Blood Flow (CBF)
Time frame: All data will be collected at the single study session (Day 1).
Changes in brain blood flow and oxygen levels will be measured using non-invasive MRI-based brain imaging methods. These scans will assess how much blood is reaching brain tissue and how oxygen levels in the brain change over time.
1 secondary outcome
Pain Ratings
Time frame: All data will be collected at the single study session (Day 1).
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Jun 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing Active Cannabis in people with Sciatica and Lumbar Radiculopathy, run by University of California, San Diego at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 12 inclusion and 17 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 3 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Madelynn Meredith, BS (619-431-1850, mameredith@health.ucsd.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Cerebral Blood Flow (CBF) (time frame: All data will be collected at the single study session (Day 1).). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Jun 2026.