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The effects of preemptive analgesia with NSAIDs or tramadol in dogs undergoing cutaneous tumor removal
Purpose of Study
This study is to test if dogs with tumors benefit from treatment with pain medications prior to removal of those tumors.
Cancer is highly prevalent among dogs; over 50% of dogs over 10 years of age die from or are euthanized due to cancer. Studies in human oncology patients have shown that 30-50% of cancer patients will experience moderate to severe pain. Tramadol is widely used in human and veterinary medicine for mild to moderate pain relief. Cancer pain can be characterized by components of bone, visceral and neuropathic pain, and many patients have central as well as peripheral sensitization. The World Health Organization considers NSAIDs to be the first tier of pain control in cancer patients, as inflammation is a major component of oncologic pain. Common side effects of NSAIDs in dogs are GI toxicity, impairment of renal blood flow, hepatopathy and impairment of coagulation. Thus, preoperative administration of NSAIDs is not appropriate for many oncologic patients. One study demonstrated that preemptive use of gabapentin for forelimb amputations in greyhounds with osteosarcoma was ineffective. The pharmacologic activity of tramadol includes weak mu opioid receptor agonism, inhibition of norepinephrine and serotonin reuptake and inhibition of 5HT reuptake. Thus, tramadol can potentially provide pain control at multiple points in the pain pathway, including the inflammatory pathway via inhibition of 5HT reuptake. Studies in human oncologic patients have shown that preemptive use of tramadol can reduce postoperative analgesia requirements. To date, no studies have compared the efficacy of NSAIDs to tramadol in veterinary oncologic patients.
To qualify for enrollment in this study, dogs must:
- Dogs with diagnosed skin tumors (sarcomas, carcinomas, melanomas, histiocytic sarcomas, mast cell tumors and benign tumors such as lipomas and adenomas) that measures at least 1cm in size are eligible for enrollment. Must be a low-risk anesthetic candidate.
- Dogs must not currently be receiving any nonsteroidal anti-inflammatory drugs (NSAIDs), steroids or pain medications.
- Dogs must be free from any serious underlying disorder (i.e., kidney, liver or heart disease).
- Dogs must be ≥ 5kg.
Your dog will need to have diagnosis of a skin tumor (sarcomas, carcinomas, melanomas, histiocytic sarcomas, mast cell tumors and benign tumors such as lipomas and adenomas) to participate in this study. Initially your dog will undergo a series of diagnostic tests, which may include blood tests, urinalysis, needle aspirations of the tumor and lymph nodes, chest x-rays/ultrasound and examination of the abdomen. The results of these initial staging tests will determine if your dog is eligible to enter this clinical trial. These tests are routinely performed when evaluating dogs with skin tumors. Once your dog has been deemed eligible to enter the study, he/she will be randomized to receive no treatment, an NSAID, or a low level narcotic for two days prior to surgery. You will also be required to complete a survey that helps to categorize your dog’s pain before treatment, prior to surgery, and post-surgery. Lastly, your dog’s pain will be assessed by study team members before and after treatment
Clients participating in this study will be given special financial considerations. The study will pay for preoperative pain medication, the initial oncology consultation, preoperative diagnostics and a portion of the subsequent surgery up to a total of $1000. Clients will be responsible for all additional costs.
Phillip Lerche, BVSc, PhD, DACVA; Nicole Karrasch, DVM