Study 1

Gamble et al. 2018 [3]

Method:

• Treatment group - CBD oil (dose 2mg/kg). vs control group - placebo oil, every 12 h for 4 weeks
• Dogs were allowed to continue NSAIDs, fish oil, and/or glucosamine/chondroitin sulphate.
• Other analgesic medications used, such as gabapentin and tramadol, were discontinued at least 2 weeks prior to enrolment.

Findings:

• Clinically, canine brief pain inventory and Hudson activity scores showed a significant decrease in pain and increase in activity (p < 0.01) with CBD oil.
• Veterinary assessment showed decreased pain during CBD treatment (p < 0.02).
• No side effects were reported by owners
• Increase in ALP during CBD treatment (p < 0.01).

Study 2

Martello et al. 2019 [4]

Sample:

• 8 client-owned dogs diagnosed with OA.
• Inclusion criteria: confirmed radiographic and clinical signs of OA.
• Exclusion criteria: evidence of other diseases based on clinical history and blood test results, acute pain, recent trauma or surgery on any joint in the previous 6 months, neurological conditions, medications or diet supplements given in the two weeks before the enrolment in the study.

Method:

• Tablets containing a preparation of natural ingredients were administered for 30 days.
• Active ingredients were CBD isolate (99.9%), hempseed oil, Boswellia and powdered melon fruit pulp. CBD dose range given was around 2.56 mg per 15 kg of body weight.

Findings:

• Using Helsinki chronic pain index (HCPI), there was a significant reduction in pain scores after 30 days.

Study 3

Kogan L, Hellyer P & Downing R 2020 [5]

Method:

• Use of NSAIDs, tramadol or amantadine was restricted
• Gabapentin and polysulphated glycosaminoglycan was allowed
• All dogs starting dose of full spectrum CBD at 0.25mg/kg QID on food
• CBD dose was adjusted as needed in response to pain assessment. Dose escalations of 0.5 to 0.75mg/kg BID were made.

Findings:

• A wide range of CBD doses (0.3 to 4.12 mg/kg body weight) were needed to achieve analgesic effects.
• Some dogs responded to small doses of CBD while others required larger doses for the same effect, suggesting different pain tolerance in dogs and different dosage requirements.
• For dogs given gabapentin, the addition of CBD supplementation allowed a third of the dogs to wean off the drug, and another one-third of the dogs were able to have their doses reduced.

Study 4

Brioschi et al. 2020 [6]

Method:

• Dogs randomly divided into two groups:
• Treatment (n = 9) group given CBD @ 2mg/kg BID + pharmaceuticals (NSAID, gabapentin, amitriptyline)
• Control group given pharmaceuticals only, no CBD
• Dogs were evaluated by owners using the Canine Brief Pain Inventory scoring system before treatment initiation (T0), and one (T1), two (T2), four (T3) and twelve (T4) weeks thereafter.

Findings:

• Pain Severity Score was significantly lower in CBD vs control group
• Pain Interference Score was significantly lower in CBD vs control group
• Quality of Life Index was significantly higher in CBD group

Study 5

Verrico et al. 2020 [7]

Sample:

• 20 large client-owned dogs (> 20 kg)
• Inclusion criteria: dogs that 1) received an affirmative diagnosed of OA by a veterinarian and 2) demonstrated signs of pain according to assessment by their owners, detectable lameness on visual gait assessment, and painful joint(s) upon palpation.
• Exclusion: No cases of OA were related to trauma, and no animals with end-stage disease were enrolled.

Method:

• All other medications were discontinued at least 2 weeks prior to enrolment and during the study
• Groups: (1) placebo, (2) 20 mg/day (0.5 mg/kg) naked CBD (99.9% CBD isolate), (3) 50 mg/day (1.2 mg/kg) naked CBD (99.9% CBD isolate), or (4) 20 mg/day liposomal CBD.

Findings:

• Animals given a high dose of naked CBD or a low dose of liposomally-encapsulated CBD experienced significant improvements in quality of life scores
• No significant effect for animals given placebo or those given a low daily dose of naked CBD.

Study 6

Mejia et al. [8]

Method:

• Dogs were randomly allocation to either placebo or CBD treatment for 6 weeks, then 6 weeks with the opposite treatment.
• Outcome measures included objective gait analysis, activity counts (via accelerometry) and clinical metrology instruments.

Findings:

• There were no differences noted between groups at any time point for any of the recorded outcome measures.
• Adverse events associated with CBD administration included elevation in liver enzymes (n = 14) and vomiting (n = 2).