analgesia nd anesthesia in dogs nd cats with drugs dosge in detail
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analgesia anesthesia dogs cats drug dosage veterinary 2024
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Here is a detailed, structured reference on analgesia and anesthesia in dogs and cats with drug dosages.
Analgesia and Anesthesia in Dogs and Cats - Detailed Drug Dosage Reference
1. PRINCIPLES OF VETERINARY PAIN MANAGEMENT
The goal is multimodal analgesia - using drugs with different mechanisms together to achieve better pain control at lower individual doses. The standard approach follows these phases:
- Premedication - sedation + preemptive analgesia before induction
- Induction - render unconscious for intubation
- Maintenance - keep anesthetized during procedure
- Recovery / Post-op analgesia - manage pain as animal wakes and afterwards
2. ANTICHOLINERGICS (Pre-Anesthetic)
Used to prevent bradycardia and reduce secretions. Given SC, IM, or IV.
| Drug | Dog Dose | Cat Dose | Route | Notes |
|---|---|---|---|---|
| Atropine | 0.02-0.04 mg/kg | 0.02-0.04 mg/kg | IV, IM, SC | Rapid acting; use for bradycardia |
| Glycopyrrolate | 0.005-0.02 mg/kg | 0.005-0.01 mg/kg | IM, SC | Does not cross BBB; preferred in cats |
3. SEDATIVES / PREMEDICATION
Phenothiazines (Tranquilizers)
| Drug | Dog Dose | Cat Dose | Route | Notes |
|---|---|---|---|---|
| Acepromazine | 0.02-0.05 mg/kg (max 2 mg total) | 0.05-0.1 mg/kg (max 1 mg total) | IM, SC, IV | No analgesia; reduces MAC of inhalants; avoid in Boxers, sighthounds, MDR1+ dogs; causes hypotension |
Benzodiazepines
| Drug | Dog Dose | Cat Dose | Route | Notes |
|---|---|---|---|---|
| Midazolam | 0.2-0.4 mg/kg | 0.1-0.3 mg/kg | IM, IV | Muscle relaxation, anti-anxiety; minimal cardiovascular effects; reversal: flumazenil |
| Diazepam | 0.25-0.5 mg/kg | 0.25-0.5 mg/kg | IV only | Cannot give IM (precipitation); use for induction co-induction |
Alpha-2 Agonists (Sedation + Analgesia)
| Drug | Dog Dose | Cat Dose | Route | Notes |
|---|---|---|---|---|
| Dexmedetomidine | 2-10 mcg/kg | 10-40 mcg/kg | IM, SC, IV | Profound sedation + analgesia; bradycardia; reversal: atipamezole (5x dose IM); avoid in cardiovascular disease; cats need higher doses |
| Xylazine | 0.5-1.0 mg/kg | 0.5-1.0 mg/kg | IM, IV | Older agent; less selective than dexmedetomidine; reversal: yohimbine or atipamezole |
4. OPIOID ANALGESICS
Pure Mu Agonists (Strongest Analgesia)
| Drug | Dog Dose | Cat Dose | Route | Frequency | Notes |
|---|---|---|---|---|---|
| Morphine | 0.5-1.0 mg/kg | 0.1-0.2 mg/kg | IM, SC (not IV - histamine) | q 4-6 h | Gold standard; causes sedation; avoid rapid IV in dogs; emesis common in dogs; euphoria in cats (use cautiously) |
| Hydromorphone | 0.1-0.2 mg/kg | 0.05-0.1 mg/kg | IM, SC, IV | q 4-6 h | 5x more potent than morphine; preferred to morphine IV; hyperthermia possible in cats |
| Oxymorphone | 0.05-0.1 mg/kg | 0.05-0.1 mg/kg | IM, SC, IV | q 4-6 h | Similar to hydromorphone |
| Fentanyl | 2-5 mcg/kg bolus; CRI 0.1-0.6 mcg/kg/min | 1-3 mcg/kg; CRI 0.05-0.3 mcg/kg/min | IV | Continuous infusion | Ultra-short acting; ideal for intraoperative CRI; fentanyl patch: 25-100 mcg/h (dogs), 25 mcg/h (cats) |
| Methadone | 0.1-0.5 mg/kg | 0.1-0.3 mg/kg | IM, SC, IV | q 4-8 h | NMDA antagonist properties; minimal emesis; good perioperative choice |
Partial Mu Agonist
| Drug | Dog Dose | Cat Dose | Route | Frequency | Notes |
|---|---|---|---|---|---|
| Buprenorphine | 0.01-0.02 mg/kg | 0.01-0.03 mg/kg | IM, IV, OTM | q 6-12 h | OTM (oral transmucosal) very effective in cats; ceiling effect at high doses; partial reversal only with naloxone; long duration |
Kappa/Mixed Agonist-Antagonists
| Drug | Dog Dose | Cat Dose | Route | Frequency | Notes |
|---|---|---|---|---|---|
| Butorphanol | 0.1-0.4 mg/kg | 0.1-0.4 mg/kg | IM, SC, IV | q 1-2 h | Moderate analgesia; mild sedation; short duration; good as premedication; reverses pure mu effects if given after |
Opioid Reversal
| Drug | Dose | Route | Notes |
|---|---|---|---|
| Naloxone | 0.01-0.04 mg/kg | IV, IM | Reverses all opioid effects including analgesia; titrate carefully |
5. NSAIDs (Non-Steroidal Anti-Inflammatory Drugs)
Critical notes: Only give if patient is well-hydrated, normotensive, and not bleeding. Do NOT combine two NSAIDs. Do NOT use with corticosteroids. Cats are very sensitive - use with extreme caution and at lower doses.
| Drug | Dog Dose | Cat Dose | Route | Frequency | Notes |
|---|---|---|---|---|---|
| Meloxicam | 0.2 mg/kg loading, then 0.1 mg/kg | 0.1 mg/kg single dose (1x); long-term: 0.025-0.05 mg/kg | SC, PO | q 24 h | Drug of choice for cats - use once or very cautiously long-term; GI/renal risk |
| Carprofen | 4 mg/kg/day (or 2.2 mg/kg BID) | Not recommended | SC, PO | q 24 h (or q 12 h) | Dogs only; hepatotoxicity reported |
| Robenacoxib | 1-2 mg/kg | 1 mg/kg | PO, SC | q 24 h | COX-2 selective; approved for cats |
| Grapiprant | 2 mg/kg | Not approved | PO | q 24 h | EP4 receptor antagonist; spares COX pathway |
| Ketoprofen | 1-2 mg/kg | 1 mg/kg (max 5 days) | IM, SC, PO | q 24 h | Short-term use; avoid in renal disease |
6. ANESTHETIC INDUCTION AGENTS
Propofol
| Species | Dose | Route | Notes |
|---|---|---|---|
| Dog | 4-6 mg/kg (unpremedicated); 1-4 mg/kg (premedicated) | IV slowly | Inject 1 mg/kg q 15 sec to effect; apnea if too fast; short duration (10-15 min); no analgesia |
| Cat | 4-8 mg/kg (unpremedicated); 2-4 mg/kg (premedicated) | IV slowly | Repeated use causes Heinz body anemia in cats; use cautiously |
Ketamine
| Species | Dose | Route | Notes |
|---|---|---|---|
| Dog | 5-10 mg/kg IM (1-3 mg/kg IV with benzodiazepine) | IM or IV | Dissociative anesthetic; maintains airway reflexes; increases HR and BP; provides analgesia; always combine with benzodiazepine to prevent muscle rigidity and seizures |
| Cat | 10-20 mg/kg IM; 2-5 mg/kg IV | IM or IV | Very common induction in cats; "Kitty Magic" combination used widely |
Alfaxalone
| Species | Dose | Route | Notes |
|---|---|---|---|
| Dog | 1-3 mg/kg IV (premedicated); up to 2 mg/kg IM | IV, IM | Neurosteroid; smooth induction; repeated IM dosing possible |
| Cat | 2-5 mg/kg IV; 5-10 mg/kg IM | IV, IM | Excellent for cats; less cumulative effect than propofol |
Thiopental (Thiopentone)
| Species | Dose | Route | Notes |
|---|---|---|---|
| Dog | 10-12 mg/kg IV (unpremedicated); 4-8 mg/kg (premedicated) | IV | Largely replaced by propofol; causes dose-dependent cardiovascular depression; greyhounds metabolize slowly |
| Cat | Not recommended | - | Cats metabolize poorly |
7. COMMON INDUCTION DRUG COMBINATIONS
| Combination | Dog Dose | Cat Dose | Notes |
|---|---|---|---|
| Ketamine + Midazolam ("K/M") | 5 mg/kg K + 0.28 mg/kg M | 5-10 mg/kg K + 0.25 mg/kg M | IM or IV; can mix in same syringe; 10-20 min duration |
| Ketamine + Diazepam | 5 mg/kg K + 0.25 mg/kg D | Same | Diazepam IV only |
| Ketamine + Dexmedetomidine + Butorphanol ("Doggie/Kitty Magic") | 1-3 mg/kg K + 2-10 mcg/kg D + 0.1-0.2 mg/kg B | 5-10 mg/kg K + 20-40 mcg/kg D + 0.2-0.4 mg/kg B | IM; excellent field anesthesia; provides analgesia + anesthesia |
| Tiletamine + Zolazepam (Telazol) | 2 mg/kg IV; 5 mg/kg IM | 4-6 mg/kg IM | Fractious animals; longer recovery; rough emergence |
| Propofol + Fentanyl | 3-5 mg/kg P + 2-5 mcg/kg F | 3-5 mg/kg P + 1-3 mcg/kg F | IV; smooth induction with analgesia |
8. INHALANT ANESTHETIC MAINTENANCE
| Drug | Induction Concentration | Maintenance Concentration | Notes |
|---|---|---|---|
| Isoflurane | 3-5% | 1.5-2.5% | Most common; depresses cardiovascular system dose-dependently; MAC dog ~1.3%, cat ~1.6% |
| Sevoflurane | 5-8% | 2.5-3.5% | Faster induction/recovery; less pungent; better for mask induction especially cats; more expensive |
| Desflurane | Not for mask induction | 6-10% | Fastest recovery; requires specialized vaporizer; pungent - avoid mask use |
MAC-sparing through multimodal analgesia (CRIs, epidurals, local blocks) reduces inhalant requirements by 20-50%.
9. CONSTANT RATE INFUSIONS (CRI) - Intraoperative Analgesia
MLK Protocol (Morphine + Lidocaine + Ketamine)
Dogs: Mix 60 mg Morphine + 500 mg Lidocaine + 60 mg Ketamine in 500 mL LRS; deliver at 1 mL/kg/hr
Loading doses first:
- Morphine: 0.5 mg/kg IM or slow IV
- Lidocaine: 0.5-1.0 mg/kg IV
- Ketamine: 0.25-0.5 mg/kg IV
Not recommended in cats (lidocaine CRI can be toxic)
Individual CRIs
| Drug | Dog CRI | Cat CRI | Notes |
|---|---|---|---|
| Fentanyl | 0.1-0.6 mcg/kg/min | 0.05-0.3 mcg/kg/min | Excellent intraoperative opioid CRI |
| Morphine | 0.1-0.3 mg/kg/h | Use cautiously 0.05-0.1 mg/kg/h | |
| Ketamine | 0.1-0.6 mg/kg/h | 0.1-0.3 mg/kg/h | Sub-anesthetic; NMDA antagonist analgesia |
| Lidocaine | 25-80 mcg/kg/min | Avoid CRI | Systemic local anesthetic; anti-inflammatory; reduce inhalant requirements |
| Dexmedetomidine | 0.5-3 mcg/kg/h | 0.5-1 mcg/kg/h | Alpha-2 sedation/analgesia CRI |
10. LOCAL AND REGIONAL ANESTHESIA
| Drug | Dose (Dog & Cat) | Route | Duration | Notes |
|---|---|---|---|---|
| Lidocaine 2% | 2-4 mg/kg (dog); 2 mg/kg max (cat) | Infiltration, nerve block | 1-2 h | Faster onset; add epinephrine to prolong |
| Bupivacaine 0.25-0.5% | 1-2 mg/kg (dog); 1 mg/kg max (cat) | Infiltration, nerve block, epidural | 4-8 h | Slower onset, longer duration; cardiotoxic if IV - never exceed dose |
| Ropivacaine 0.2-0.5% | 1-3 mg/kg | Nerve block, epidural | 4-6 h | Less cardiotoxic than bupivacaine |
| Epidural Morphine | 0.1 mg/kg in 0.1 mL/kg saline | Lumbosacral epidural | 12-24 h | Excellent post-op analgesia for hindlimb/abdominal surgery |
| Epidural Bupivacaine | 1 mg/kg | Lumbosacral | 4-6 h | Motor block too |
Common blocks:
- Dental/maxillary/mandibular nerve blocks: lidocaine or bupivacaine (vital for dental procedures)
- RUMM block / PECS block: thoracic surgery
- Intercostal blocks: thoracotomy
- Brachial plexus block: forelimb surgery
- Femoral + sciatic nerve block: hindlimb surgery
11. ADJUNCT ANALGESICS
| Drug | Dog Dose | Cat Dose | Route | Notes |
|---|---|---|---|---|
| Tramadol | 2-5 mg/kg | 1-2 mg/kg | PO | q 8-12 h; mu-agonist + monoamine reuptake inhibitor; less effective in dogs (poor metabolism to active M1); useful in cats |
| Gabapentin | 5-10 mg/kg | 5-10 mg/kg | PO | q 8-12 h; neuropathic pain; chronic pain; pre-operative anxiolysis; sedation common |
| Amantadine | 3-5 mg/kg | 3-5 mg/kg | PO | q 24 h; NMDA antagonist; used for chronic pain/wind-up |
| Maropitant (Cerenia) | 1 mg/kg | 1 mg/kg | SC, PO | Pre-op 1-2h; anti-emetic with visceral analgesic properties; 1 mg/kg SC pre-operatively reduces inhalant requirements |
12. NEUROMUSCULAR BLOCKING AGENTS (if needed)
| Drug | Dog Dose | Duration | Notes |
|---|---|---|---|
| Atracurium | 0.1-0.4 mg/kg IV; CRI 3-9 mcg/kg/min | 20-40 min | Non-depolarizing; reversal: neostigmine |
| Vecuronium | 0.1 mg/kg IV | 25 min | Non-depolarizing; must have ventilator support |
| Pancuronium | 0.05-0.1 mg/kg IV | 45-60 min | Longer duration |
| Succinylcholine | 0.3 mg/kg IV | 5-10 min | Depolarizing; rapid onset; for intubation; causes fasciculations |
Critical: Never use NMBAs without full inhalant anesthesia and ventilatory support. These cause paralysis but NOT anesthesia or analgesia.
13. SPECIES-SPECIFIC CONSIDERATIONS
Dogs
- Acepromazine max 2 mg total dose regardless of weight
- Avoid acepromazine in Boxers (vasovagal syncope risk), sighthounds (slow metabolism), MDR1+ breeds (Collies, Shelties, Aussies - use 50% dose reductions for many drugs)
- Lidocaine CRI is safe and useful in dogs
- NSAIDs generally well-tolerated with appropriate patient selection
Cats
- Avoid: aspirin, ibuprofen, acetaminophen (paracetamol) - highly toxic, can be fatal
- Acepromazine max 1 mg total dose
- Ketamine commonly used - must combine with a benzodiazepine or alpha-2 agonist
- Propofol with repeated dosing causes Heinz body anemia - use alfaxalone as alternative
- Morphine can cause hyperthermia (pyrexia) and excitation - monitor closely
- Buprenorphine OTM (oral transmucosal) is highly effective due to cat's alkaline saliva
- Lidocaine CRI - use with extreme caution or avoid in cats (low therapeutic index)
- Meloxicam in cats: approved for single perioperative dose SC; long-term use is controversial but used at very low doses (0.025 mg/kg/day)
14. ANALGESIC LADDER BY PAIN SEVERITY
| Pain Level | Drug Choice |
|---|---|
| Mild (minor wounds, dental) | NSAIDs ± butorphanol or buprenorphine, gabapentin |
| Moderate (soft tissue surgery) | Opioid (hydromorphone/buprenorphine) + NSAID + local block |
| Severe (orthopedic, thoracic) | Full mu opioid (morphine/fentanyl CRI) + NSAID + local/regional block + ketamine CRI |
| Chronic/Neuropathic | Gabapentin + amantadine + tramadol ± NSAID |
15. QUICK REFERENCE - ANESTHESIA PROTOCOL SUMMARY
Standard Protocol (Healthy Dog or Cat):
- Premedicate (IM, 15-20 min before): Dexmedetomidine 5 mcg/kg + Hydromorphone 0.1 mg/kg ± Acepromazine 0.02 mg/kg
- Induce (IV): Propofol 1-4 mg/kg to effect, OR Alfaxalone 1-2 mg/kg to effect
- Intubate and maintain on Isoflurane 1.5-2.5% in oxygen
- Intraoperative analgesia: Fentanyl CRI 0.1-0.3 mcg/kg/min ± local blocks
- Recovery: NSAID (meloxicam/carprofen) + buprenorphine or hydromorphone
- Home: NSAID ± tramadol (dogs) or buprenorphine OTM (cats)
Important disclaimer: All doses listed are general veterinary guidelines. Actual dosing must be individualized based on patient signalment, body condition score, organ function, concurrent medications, and clinical judgment. Always consult current formularies (Plumb's Veterinary Drug Handbook) and a veterinary anesthesiologist for complex cases. Drug availability and regulatory status varies by country.
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