Acute Pain Analgesia in Cats: Moving Beyond the Drug

For many years, the focus in pain management revolved around which drug, what dose, and what frequency. However, our understanding has evolved. We now recognize that effective acute pain management requires a well-thought-out analgesic plan, which encompasses the pharmacological protocol but also the emotional needs of the cat, fine-friendly handling techniques, and a focus on minimizing stress and anxiety.

Key Considerations for Your Analgesic Plan

Before diving into specific drugs, several general considerations are crucial:

· Feline Drug Metabolism: Cats metabolize and eliminate drugs differently than dogs. For example, drugs metabolized by glucuronidation (like paracetamol, which should never be given to cats, as well as ketoprofen and morphine) are excreted more slowly. Conversely, some drugs undergoing oxidation (like meloxicam, robenacoxib, buprenorphine, and meperidine) are eliminated more rapidly in cats. Understanding these differences is vital for choosing appropriate drugs, dosages, and administration intervals.

· Comorbidities: The presence of conditions like chronic kidney disease (CKD), which affects a significant portion of older cats, necessitates adjustments in drug selection and dosing intervals. The effects of drugs may be less predictable in these patients. For instance, the accumulation of ketamine and its active metabolite can occur in cats with impaired kidney function. While NSAID use in stable IRIS 1 and 2 CKD cats has been discussed, caution and minimum effective doses are key. Similarly, gabapentin doses may need reduction in CKD patients due to renal excretion.

Principles Guiding Acute Pain Management

The foundation of effective acute pain management in cats rests on these principles:

· Preventive Analgesia: This concept goes beyond preemptive analgesia (administering analgesics before surgery) and includes all peroperative techniques aimed at decreasing postoperative pain, such as administering NSAIDs at the end of a procedure or early postoperative opioid doses. Analgesics should be administered whenever needed for pain relief.

· Multimodal Analgesia: This involves using two or more analgesics with different mechanisms of action to achieve a synergistic effect, allowing for lower doses of each drug and minimizing adverse effects. Importantly, multimodal analgesia includes not only drugs but also non-pharmacological therapies.

Building Your Analgesic Protocol: Key Questions

When constructing an analgesic protocol, consider these questions:

1. Is there a local anesthetic block that I can use? Local blocks (e.g., for castration, ovariohysterectomy, dental procedures) provide early postoperative analgesia, reduce anesthetic requirements, and can blunt sympathetic responses to surgery. Don't underestimate the value of these "day one skills".

2. What is my opioid of preference? While morphine and hydromorphone are effective, their association with peroperative vomiting often leads to the preference of other opioids like methadone (for moderate to severe pain) and buprenorphine (for mild to moderate pain, especially in combination with local anesthetics and NSAIDs). Fentanyl or remifentanil infusions may be used when required. Opioid-sparing approaches, using a single dose of buprenorphine in combination with NSAIDs and local blocks, are also showing promise.

3. Are there any contraindications for nonsteroidal anti-inflammatory drugs (NSAIDs)? NSAIDs are valuable for managing inflammation associated with surgery. However, strict contraindications (e.g., anorexia, vomiting, diarrhea, hypovolemia, severe dehydration, unstable renal or liver disease) must be respected. When appropriate, meloxicam and robenacoxib have evidence for safe use over multiple days. Fear alone should not prevent the responsible use of NSAIDs.

4. Is there a need for adjuvant analgesics? These drugs enhance analgesia when used as part of a multimodal plan. Examples include dexmedetomidine (for sedation, reduced anesthetic requirements, and some visceral analgesia), ketamine infusions (for preventing or treating central sensitization), tramadol (injectable form widely used in some regions, oral form has palatability challenges in cats), and gabapentin (potential role in peroperative pain management and anxiety reduction).

The "TALES" concept (Type of noxious stimulation, Anticipated duration, Location, Patient - inpatient/outpatient, Severity) can further guide your choices of analgesic drugs, doses, frequency, and routes of administration.

The Crucial Role of a Holistic Approach

Effective pain management extends beyond drugs:

· Pre-anesthetic Care: Consider pre-medication starting at home for anxious cats, potentially including gabapentin to reduce stress during transportation.

· Anti-emetics: Addressing nausea and vomiting, especially with opioids, is vital for patient comfort. Maropitant, a neurokinin-1 receptor antagonist, is particularly useful in this regard.

· Nursing Care: The importance of skilled veterinary nurses and technicians cannot be overstated. Their role in patient positioning, environmental comfort, nutritional support, fluid therapy, bladder care, and feline-friendly handling is fundamental.

· Non-Pharmacological Therapies: Proper wound care is essential, and the impact of bandaging on feline stress should be considered carefully. Cold therapy may have a role in reducing localized inflammation.

· Environment: Creating a calm, quiet, and comfortable hospital environment, separating cats from dogs, and providing hiding spaces are crucial for minimizing stress.

· Home Medications: Clear instructions to owners regarding a comfortable home environment and ensuring palatable medication administration are essential for continued pain management.

Looking Towards the Future

The field of feline pain management is continually advancing, with exciting developments like monoclonal antibodies for chronic pain and the FDA approval of transdermal buprenorphine for postsurgical pain offering new options. The development of automated pain assessment tools using artificial intelligence also holds great promise.

The Indispensable Role of Pain Assessment

Finally, remember that a well-designed analgesic plan must always include pain assessment to ensure its effectiveness. Utilize available resources like the Feline Grimace Scale to objectively evaluate your patients' pain levels.

Conclusion

Achieving optimal acute pain analgesia in cats requires a multifaceted approach. By understanding feline physiology, embracing preventive and multimodal strategies, carefully selecting analgesic drugs, addressing non-pharmacological factors, and continuously assessing our patients, we can significantly improve their comfort and well-being. Don't forget to consult the ISFM acute pain management guidelines for a comprehensive resource!