Table 1.
Characteristics of included studies.
| First author, year | Study design | Study population | Intervention (n) | Control (n) | Treatment duration | Funding source |
|---|---|---|---|---|---|---|
| Single arm study | ||||||
| Kogan, 2020 (24) | Single arm | Client-owned dogs with osteoarthritis | Oral full-spectrum CBD oil 0.25 mg/kg once daily for 3 days, then escalated to 0.50–0.75 mg/kg every 12 h until pain severity score (0–10) was 0–1 (n = 37) (dogs were allowed to continue using gabapentin, polysulfated aminoglycan, and acupuncture) | No control group | 12 weeks | Not reported |
| Parallel randomized controlled study | ||||||
| Brioschi, 2020 (22) | - Parallel - Randomized - Owner blinded |
Client-owned dogs with radiographic-confirmed osteoarthritis | Oral transmucosal full-spectrum CBD oil 2 mg/kg every 12 h plus standard of care [combination of NSAIDs (or corticosteroid if NSAIDs were contraindicated), gabapentin, and amitriptyline] (n = 9) | Standard of care [combination of NSAIDs (or corticosteroid if NSAIDs were contraindicated), gabapentin, and amitriptyline] (n = 12) | 12 weeks | No external funding received |
| Verrico, 2020 (27) | - Parallel - Randomized - Placebo-controlled - Veterinarian and owner blinded |
Client-owned dogs with osteoarthritis | - Oral isolated CBD oil 0.5 mg/kg every 12 h (n = 5) - Oral isolated CBD oil 1.2 mg/kg every 12 h (n = 5) - Oral liposomal CBD oil 0.5 mg/kg every 12 h (n = 5) |
Placebo oil (fractionated coconut oil) (n = 5) | 4 weeks | -Medterra CBD, Inc. - Baylor College of Medicine—NIH |
| Cross-over randomized controlled study | ||||||
| Gamble, 2018 (18) | - Cross-over - Randomized - Placebo-controlled - Veterinarian and owner blinded |
Client-owned dogs with radiographic-confirmed osteoarthritis | Oral full-spectrum CBD oil 2 mg/kg every 12 h plus standard of care (NSAIDs, fish oil, and/or glucosamine sulfate, chondroitin sulfate) (n = 16) | Placebo oil (olive oil with 10 PPT anise oil and 5 PPT peppermint oil) plus standard of care (NSAIDs, fish oil, and/or glucosamine sulfate, chondroitin sulfate) (n = 16) | 10 weeks (4-2-4)* | Ellevet LLC |
| Mejia, 2021 (26) | - Cross-over - Randomized - Placebo-controlled - Veterinarian and owner blinded |
Client-owned dogs with radiographic-confirmed osteoarthritis | Oral full-spectrum CBD oil 2.5 mg/kg every 12 h (n = 23) | Placebo oil (n = 23) | 12 weeks (6-0-6)* | Not reported |
*Three numbers in parenthesis indicate (1) duration of treatment A, (2) wash-out period before cross-over, and (3) duration of treatment B. CBD, cannabidiol; NSAIDs, nonsteroidal anti-inflammatory drugs; PPT, parts per thousands.