The goal of pain management in patients with acute spinal pain is not only to relieve the pain they are actively experiencing but also to prevent pathologic or chronic pain from developing. Acute pain is localized pain that is part of the body's mechanism to protect from injury, but chronic pain serves no protective function. Chronic pain can also lead to allodynia, where a minimal stimulus can be perceived as being painful. Medications for acute pain are therefore aimed at preventing peripheral sensitization, transmission of pain, central sensitization, modulation and projection of pain. While non-steroidal antiinflammatories or corticosteroids can help reduce tissue inflammation and reduce pain, other medications and treatment modalities can be considered for dogs whose pain is not well-controlled. In addition to medication, other potential therapies include acupuncture, laser therapy, and physical therapy.
The following chart lists options for medications for pain management:
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Dosage
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Side effects
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Opioids
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Fentanyl patch
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5 mcg/kg/h transdermal
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Sedation, urine retention
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Codeine
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1–2 mg/kg PO q 6–8 h
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Sedation, constipation
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Tramadol
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2–5 mg/kg PO q 6–12 h
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Gastrointestinal upset, sedation, constipation
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Recuvyra (transdermal fentanyl)
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Dosing table from company - requires mandatory training video, cannot redose within 7 days
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Hypothermia, urine retention, sedation, inappetence, nausea
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NMDA receptor antagonists
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Amantadine
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3–5 mg/kg PO q 24 h, may take a couple of weeks to show effect
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Diarrhea, agitation, flatulence
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Anticonvulsants
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Gabapentin
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2–10 mg/kg PO q 8–12 h
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Sedation
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Pregabalin
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4 mg/kg PO q 12 h
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Sedation
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Tricyclic antidepressants
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Amitriptyline
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1–2 mg/kg PO q 12–24 h
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Sedation, vomiting, dysphoria
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Clomipramine
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1–3 mg/kg PO q 12 h (must give for at least 4 weeks)
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Vomiting, diarrhea, sedation, dry mouth, tachycardia
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Muscle relaxant
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Methocarbamol
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15–20 mg/kg PO q 8 h
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Sedation, lethargy, ataxia
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Acupuncture
Acupuncture is generally considered a safe therapy and is becoming more widely available, but the effectiveness for pain relief has not been rigorously tested in dogs following back surgery. In traditional Chinese medicine theory, the insertion of needles along meridians regulates the flow of energy (qi) through the body. Acupuncture may decrease muscle spasms, promote endorphin and serotonin release and may prevent central sensitization in neuropathic pain. A study in dogs reported that electroacupuncture in combination with decompressive spinal surgery helped in alleviating back pain more than decompressive surgery alone.
Laser Therapy
The use of therapeutic lasers is becoming more common in practice. Low-level laser therapy uses light to stimulate cells for tissue healing by stimulating angiogenesis. Low-level laser therapy has also been reported to aid in pain control in dogs. Laser therapy may promote the release of endogenous opioids and suppress the levels of nitric oxide and prostaglandins to aid in pain control. While lasers have been studied, there are no strong evidence-based medicine studies in pets to confirm these claims.
Physical Therapy
There are several aspects of physical therapy that can be utilized to alleviate pain in patients with suspected intervertebral disk disease or postoperative spinal patients. Cold therapy, passive range of motion exercises and massage can be utilized, both in the hospital and by the owner at home, to help with pain management.
References
1. Canapp DA. Select modalities. Clin Tech Small Anim Pract. 2007;22(4):160–165.
2. Cantwell SL. Traditional Chinese veterinary medicine: the mechanism and management of acupuncture for chronic pain. Top Companion Anim Med. 2010;25(1):53–58.
3. Gaynor JS. Acupuncture for management of pain. Vet Clin North Am Small Anim Pract. 2000;30(4):875–884.
4. Grubb T. Chronic neuropathic pain in veterinary patients. Top Companion Anim Med. 2010;25(1):45–52.
5. Hagiwara S, Iwasaka H, Okuda K, et al. CaAlAs (830 nm) low-level laser enhances peripheral endogenous opioid analgesia in rats. Lasers Surg Med. 2007;39:797–802.
6. Laim A, Jaggy A, Forterre F, et al. Effects of adjunct electroacupuncture on severity of postoperative pain in dogs undergoing hemilaminectomy because of acute thoracolumbar intervertebral disc disease. J Am Vet Med Assoc. 2009;234:1141–1146.
7. Mathews KA. Neuropathic pain in dogs and cats: if only they could tell us if the hurt. Vet Clin North Am Small Anim Pract. 2008;38(6):1365–1414.