Veterinary Anesthesia Dose Calculator — Dog, Cat, Rabbit, Horse

How to Use This Calculator

1. Select species (dog, cat, rabbit, horse).
2. Enter patient weight in kg.
3. Select drug from the list (premedication, induction, or sedation agents).
4. Low and high dose range and volume appear instantly.
5. Use the Premedication tab to select doses by ASA status.
6. Use the Induction tab for titration guidance and premedication adjustment.
7. Use the Reversal tab to calculate atipamezole and flumazenil doses.

Formula

Example

Frequently Asked Questions

• How are veterinary anesthesia doses calculated? ▼
  Veterinary anesthesia doses are calculated using weight-based (mg/kg) dosing, with the dose in mg per kg multiplied by the patient's body weight in kilograms to give the total dose. The volume to administer is then calculated by dividing the total dose (mg) by the drug concentration (mg/mL). For example, propofol at 4 mg/kg for a 20 kg dog at 10 mg/mL concentration: 4 × 20 = 80 mg ÷ 10 mg/mL = 8 mL. Most induction agents are given "to effect" — the calculated dose represents a target starting point, but the drug is administered incrementally (titrated), observing the patient's response (loss of pedal withdrawal reflex, jaw tone relaxation, smooth induction) and stopping when the desired plane of anesthesia is achieved, rather than giving the full calculated dose rapidly. Titration is especially important because individual variation in drug sensitivity is substantial, and factors including health status (ASA grade), concurrent medications, breed, age, body condition, and prior drug exposure all affect the effective dose. Premedicated animals consistently require lower induction doses — typically 50–75% of the unpremedicated dose.
• Why are sighthounds and brachycephalic breeds higher anesthetic risk? ▼
  Sighthounds (Greyhounds, Whippets, Salukis, Borzois, Afghan Hounds) have two specific anesthetic concerns: first, they have very low body fat percentages (often < 10% compared to 20–30% in typical breeds), which means highly lipid-soluble drugs such as propofol, thiopental, and alfaxalone cannot be redistributed into fat stores and instead have prolonged circulating times, causing extended recovery. Thiopental is considered contraindicated in sighthounds for this reason; propofol and alfaxalone are preferred with reduced dosing and slow titration. Second, sighthounds appear to have reduced hepatic clearance of certain drugs due to lower cytochrome P450 enzyme activity, further extending drug duration. Brachycephalic breeds (Bulldogs, French Bulldogs, Pugs, Persian cats, etc.) have anatomical airway abnormalities — stenotic nares, elongated soft palate, hypoplastic trachea — that severely increase anesthetic risk. They are prone to airway obstruction on induction and recovery, hypoxaemia, regurgitation and aspiration (increased reflux due to conformation and increased respiratory effort), and difficult intubation. Key safety steps include: pre-oxygenation for 3–5 minutes before induction, having multiple ET tube sizes ready, rapid secure intubation, minimising extubation time (extubate late when fully awake), and recovery in sternal recumbency with head elevated.
• What is ASA grading in veterinary anesthesia? ▼
  The ASA (American Society of Anesthesiologists) Physical Status Classification System is used in veterinary anesthesia identically to its human application, with five grades: ASA I — normal healthy patient, no underlying disease (elective procedures, spay/neuter in young healthy animals); ASA II — mild systemic disease that does not limit normal activity (mild dehydration, early cardiac murmur, well-controlled diabetes, overweight); ASA III — moderate systemic disease that limits activity (moderate dehydration, cardiac disease with clinical signs, controlled renal disease, anaemia); ASA IV — severe systemic disease, constant threat to life (severe dehydration, significant cardiac or respiratory compromise, uncontrolled diabetes, uraemia, peritonitis); ASA V — moribund patient unlikely to survive 24 hours without surgery (haemoabdomen with shock, GDV with cardiovascular collapse, severe head trauma). The E suffix indicates emergency. Higher ASA grades require more conservative anesthetic protocols — reduced drug doses, invasive monitoring, and greater readiness for cardiovascular support. ACVAA and AAHA guidelines recommend that ASA III-V cases be managed by or in consultation with a board-certified veterinary anesthesiologist or experienced anesthesia team.
• What reversal agents are used in veterinary anesthesia? ▼
  Several anesthetic drugs used in veterinary practice have specific pharmacological reversal agents. Atipamezole (Antisedan) reverses alpha-2 adrenergic receptor agonists including dexmedetomidine and medetomidine. The dose is 5 times the dexmedetomidine dose in micrograms per kilogram, given intramuscularly (not IV, as rapid IV reversal can cause cardiovascular instability). Onset is typically 5–15 minutes IM. Flumazenil reverses benzodiazepines (midazolam, diazepam) at 0.01 mg/kg IV; its short half-life (30–60 minutes) means re-sedation can occur if the benzodiazepine duration exceeds that of flumazenil, requiring monitoring for 1–2 hours. Naloxone reverses opioid-induced respiratory depression and sedation at 0.02–0.04 mg/kg IV or IM; it also reverses analgesia, so judicious dosing is important to avoid leaving the patient in pain. Neostigmine (with glycopyrrolate or atropine) reverses non-depolarising neuromuscular blockers but is rarely needed with modern short-acting agents and appropriate monitoring. Yohimbine can reverse xylazine (an older alpha-2 agonist) but is not effective for dexmedetomidine — atipamezole is preferred. Physostigmine reverses anticholinergic toxicity (atropine overdose) in small animals.
• What monitoring is required during veterinary anesthesia? ▼
  ACVAA (American College of Veterinary Anesthesia and Analgesia) monitoring standards require specific minimum monitoring for all anesthetised patients. Essential monitoring includes: heart rate and rhythm (stethoscope or ECG — ECG mandatory for high-risk cases or procedures > 30 min); respiratory rate and character; SpO2 (pulse oximetry — probe on tongue, lip, toe, or vulva); end-tidal CO2 (ETCO2 — capnography, mandatory for intubated patients, target 35–45 mmHg); mucous membrane colour and capillary refill time; and core temperature (thermometer, rectal or oesophageal, every 15 minutes — hypothermia is common and causes prolonged recovery, coagulopathy, and cardiovascular depression). Strongly recommended additional monitoring includes: arterial blood pressure (non-invasive oscillometric or Doppler for maintenance; invasive arterial catheter for high-risk cases); depth of anaesthesia assessment (jaw tone, eye position, response to stimulation); and fluid administration rates. For equine anaesthesia, direct arterial pressure monitoring is essentially mandatory due to the high risk of hypotension-associated myopathy. Temperature management (warm air blankets, circulating warm water blankets, warm IV fluids) is critical for small patients (cats, rabbits, small dogs) who lose heat rapidly under anaesthesia.

Related Calculators