What Research Actually Shows About Cannabis and Sickle Cell Pain
Sickle cell disease is a group of inherited blood disorders in which abnormal hemoglobin causes red blood cells to become rigid, sticky and sickle-shaped. These cells can block blood flow, leading to anemia, episodes of severe pain and complications such as infection, stroke and acute chest syndrome. Symptoms vary widely, but chronic pain and sudden vaso-occlusive crises can significantly affect daily life.
How sickle cell disease is managed
Treatment is individualized according to a person’s disease type, symptoms and complications. Standard care may include hydroxyurea, L-glutamine, crizanlizumab, blood transfusions and prescription pain medicines. Some people may also be candidates for a bone marrow transplant or gene therapy. The National Heart, Lung, and Blood Institute’s treatment overview provides a current summary of these options.
Infection prevention is especially important during childhood. Daily penicillin is commonly prescribed for young children with HbSS, the most common and often most severe form of sickle cell disease, generally until at least age 5. Some people continue taking it longer, particularly if they have had their spleen removed or experienced certain serious infections. It is not accurate to suggest that every adult with sickle cell disease takes lifelong antibiotics.
What the research says about cannabis
Several studies have examined cannabis use among people with sickle cell disease, but they do not establish cannabis as a proven treatment.
A 2005 questionnaire study of 86 adults in the United Kingdom found that 31 participants—36 percent—had used cannabis in the previous year to relieve symptoms associated with sickle cell disease. Among those users, pain relief was the most frequently cited reason, followed by relaxation or relief of anxiety and depression. However, the study measured patients’ experiences and opinions rather than testing cannabis against a placebo. Participants also reported side effects, including sleepiness and mood changes.
A 2018 study of adults receiving care at Yale similarly documented marijuana use and interest in medical cannabis. Among 58 surveyed patients, 42 percent reported using marijuana during the previous two years. Urine testing also detected cannabinoids in some patients. The researchers concluded that the findings supported further research, not that cannabis had been shown to relieve sickle cell pain. Because the study was observational, it could not determine whether cannabis improved symptoms or whether people with more severe pain were simply more likely to use it.
The strongest clinical evidence so far
In 2020, researchers published a small randomized clinical trial in JAMA Network Open. The study included 23 adults with sickle cell disease and chronic pain. During two five-day treatment periods, participants inhaled either vaporized cannabis containing approximately equal amounts of THC and CBD or a placebo preparation. Participants continued to receive their usual opioid treatment.
The trial found that vaporized cannabis was generally safe over the short study period. It did not, however, produce a statistically significant reduction in pain ratings or most measures of pain interference compared with placebo. The cannabis group did show a significant improvement in how much pain interfered with mood. The study was small, lasted only five days for each treatment period and was not designed to determine long-term benefits or risks.
What patients should take from the evidence
Research to date suggests that some people with sickle cell disease use cannabis to manage pain, sleep difficulties, anxiety or other symptoms. It also suggests that cannabis may warrant larger and longer clinical trials. But the available evidence remains limited, and the best randomized study did not show a significant reduction in pain itself.
Cannabis should not replace disease-modifying treatment, prescribed pain care or urgent evaluation during a pain crisis. Products can vary in their THC and CBD content, and cannabis may cause sedation, dizziness, anxiety, impaired judgment or drug interactions. Anyone considering medical cannabis should discuss it with a hematologist or other qualified clinician, particularly when taking opioids or other medicines.
