Analgesia & Pain Management – Veterinary Anesthesia Lecture

Vocabulary flashcards covering key terms, neurotransmitters, drug classes, and pain-pathway concepts discussed in the veterinary analgesia lecture.

Analgesia

The absence or relief of pain without loss of consciousness.

Nociception

The physiologic process of detecting and transmitting noxious (painful) stimuli through the nervous system.

Transduction (Pain Pathway Phase 1)

Conversion of a noxious stimulus at peripheral receptors into an electrical nerve impulse.

Transmission (Pain Pathway Phase 2)

Conduction of the pain impulse along peripheral nerves to the spinal cord and brainstem.

Modulation (Pain Pathway Phase 3)

Alteration of the pain signal within the spinal cord through excitatory or inhibitory neurotransmitters.

Perception (Pain Pathway Phase 4)

Recognition of pain in the cerebral cortex, producing the conscious experience of 'ouch'.

Multimodal Analgesia

Using different drug classes and techniques to target multiple points along the pain pathway for superior pain control.

Preemptive Analgesia

Administration of analgesics before a painful stimulus to prevent central sensitization and reduce postoperative pain and anesthetic needs.

Wind-up Phenomenon

Exaggerated and persistent pain caused by repeated nociceptive stimulation leading to spinal cord hypersensitization.

CSU Pain Score System

Colorado State University’s 0–4 behavioral scoring scale for assessing canine pain.

Feline Grimace Scale

Behavioral tool that evaluates cat facial expressions (ears, eyes, muzzle, whiskers, head) to grade pain.

Hyperalgesia

Heightened or exaggerated response to a normally painful stimulus.

Allodynia

Perception of pain from a stimulus that is normally non-painful (e.g., gentle touch after injury).

Opioids

Gold-standard analgesics that bind opioid receptors (μ, κ, δ) to inhibit pain transmission, modulation, and perception.

NSAIDs (Non-Steroidal Anti-Inflammatory Drugs)

Drugs that reduce pain, inflammation, and fever primarily by inhibiting cyclooxygenase enzymes.

Cyclooxygenase (COX) Enzymes

COX-1 and COX-2 convert arachidonic acid into prostaglandins; inhibition provides NSAID effects.

COX-1

‘Constitutive’ enzyme supporting gastric mucosa, renal blood flow, and platelet function; inhibition leads to many NSAID side-effects.

COX-2

‘Inducible’ enzyme up-regulated during inflammation; selective inhibition yields analgesia with fewer GI/renal effects.

GABA (Gamma-Aminobutyric Acid)

Major inhibitory neurotransmitter that can dampen pain signals; mimicked by drugs such as gabapentin.

Gabapentin

Synthetic GABA analogue used orally for neuropathic pain and modulation of spinal transmission.

Substance P

Excitatory neurotransmitter that enhances pain transmission in the spinal cord.

Glutamate

Primary excitatory amino-acid neurotransmitter that amplifies nociceptive signaling.

Glycine

Inhibitory neurotransmitter that can suppress pain transmission within the spinal cord.

EP4 Receptor

Prostaglandin E2 receptor subtype implicated in pain and inflammation; specifically blocked by grapiprant (e.g., Galliprant).

Fentanyl

Potent μ-opioid agonist used IV bolus, CRI, transdermal patch for acute analgesia; very short plasma half-life IV.

Constant Rate Infusion (CRI)

Continuous IV delivery of a drug (e.g., fentanyl, lidocaine) to maintain steady analgesic plasma levels.

Epidural Analgesia

Administration of analgesic drugs (e.g., preservative-free morphine) into the lumbosacral epidural space for long-lasting regional pain control.

Fentanyl Patch

Transdermal system releasing micrograms of fentanyl per hour; portion can be ‘dosed’ by covering part of the patch, not by cutting.

Somatic Pain

Pain originating from skin, muscle, joints, or bones; often sharp and well localized.

Visceral Pain

Pain arising from internal organs; often dull, diffuse, and harder to localize (e.g., colic).

Ketamine (Analgesic Role)

NMDA-receptor antagonist providing strong somatic analgesia and preventing central sensitization (wind-up).

Lidocaine (Vocal-Fold Desensitization)

Local anesthetic applied topically (≈0.1 mL total in cats) to laryngeal folds to reduce intubation-related laryngospasm.

Robenacoxib (Onsior)

COX-2-selective NSAID labeled for cats and dogs; available injectable and oral; short postoperative dosing courses.

Carprofen (Rimadyl)

Veterinary NSAID (preferential COX-2) widely used for chronic canine arthritis; requires periodic liver monitoring.

Meloxicam

COX-2-preferential NSAID; chronic feline use controversial in U.S. due to potential renal/liver risks.

Grapiprant (Galliprant)

EP4-receptor antagonist NSAID-like drug that controls pain and inflammation without inhibiting COX enzymes.