Page 2927 - Cote clinical veterinary advisor dogs and cats 4th

Hydromorphone + Diazepam (or Hydromorphone + Midazolam)

Expected observable effect: heavy sedation. The animal may remain conscious Advantages: minimal cardiovascular depression
but likely will be unable to walk. Hyperresponsiveness to sound is common Drawbacks: nausea, panting
Expected duration of effect/recovery: sedative effects typically are longer than
(avoid loud noises).
VetBooks.ir Dosage and route (dog or cat): hydromorphone 0.05-0.2 mg/kg IV or IM + either butorphanol + diazepam/midazolam. Animals regain the ability to walk within
30 minutes of administration.
diazepam IV 0.1-0.2 mg/kg or midazolam 0.1-0.2 mg/kg IV or IM. The two
should be in separate syringes if diazepam is used.
dexmedetomidine 0.005 mg/kg IM or IV.
Pain control: moderate Alternatives: for greater sedation, omit diazepam/midazolam and replace with
Time to desired effect of sedation: 1-2 minutes (IV) or 5-15 minutes (IM). Notes and comments: midazolam is now available as generic (cost is similar to
Indications: sedation for restraint or minimally painful procedures that are likely diazepam).
to take < 30 minutes
Contraindications: vomiting/nauseated patient; noisy environment; liver disease
(diazepam, midazolam); hypovolemia, dehydration, marked acid-base imbalance,
or other instances of severe systemic illness
Ketamine + Diazepam*
Expected observable effect: altered consciousness and immobilization Expected duration of effect/recovery: 30-180 minutes to regain the ability to
Dosage and route (dog or cat): ketamine 3 mg/kg IV + diazepam or midazolam walk
0.1 mg/kg IV. The two drugs can be combined and given to effect. Alternatives: immobilization: propofol 3-6 mg/kg IV to effect, or dexmedetomi-
Pain control: mild dine 0.005 mg/kg IM or IV. Addition of acepromazine 0.025-0.05 mg/kg
Time to desired effect of sedation: immediate IV to ketamine + diazepam produces immobilization for 20-60 minutes (but
Indications: immobilization not analgesia). Alternatives for analgesia (see above): butorphanol + diazepam/
Contraindications: heart, liver, or neurologic disease, systemic hypertension midazolam or hydromorphone + diazepam/midazolam
Advantage: inexpensive Notes and comments: prolonged recovery, inability to reverse the drugs, and
Drawbacks: prolonged and dysphoric recovery, tachycardia; multiple contrain- multiple relative contraindications mean that this protocol has largely been
dications replaced by newer ones.
Dexmedetomidine
Expected observable effect: moderate sedation. Bursts of regained mentation can Drawbacks: causes systemic hypertension (may be marked)
occur for a few seconds spontaneously or in response to sound. Expected duration of effect/recovery: gradual over 20-30 minutes (IV)
Dosage and route (dog or cat): 0.005-0.01 mg/kg (5-10 mcg/kg) IM or IV. The Alternatives: often combined with hydromorphone 0.05-0.2 mg/kg IM or IV,
higher dose is preferred for cats. or butorphanol 0.2-0.4 mg/kg IM or IV for profound sedation and analgesia
Pain control: moderate Notes and comments: drug of choice for cats with hypertrophic or hypertro-
Time to desired effect of sedation: <1 minute (IV) or ≈5 minutes (IM) phic-obstructive cardiomyopathy. Reflex bradycardia is expected and is gen-
Indications: immobilization; component of analgesic protocol erally not treated (response to dexmedetomidine-induced marked systemic
Contraindications: systemic hypertension; AV block hypertension).
Advantages: IM injection not painful (e.g., useful for fractious cats); reversible
with same volume of atipamezole (Antisedan)

Propofol*
Expected effect: immobilization and altered/depressed consciousness without Advantages: short-lived cardiovascular depression; rapid hepatic metabolism (no
loss of pain perception accumulation in body fat)
Dosage and route (dog or cat): 3-6 mg/kg IV to effect, then titrated as needed Drawbacks: respiratory depression-apnea is common initially. No analgesic ef-
to maintain stable plane fect
Pain control: none Expected duration of effect/recovery: very brief (several minutes)
Time to desired effect of sedation: immediate Alternatives: isoflurane, sevoflurane, or other inhalant anesthetic, or alfaxalone
Indications: rapid induction of immobilization; seizure control, especially when Notes and comments: Due to (often very marked) respiratory depression, it is
caused by hepatic encephalopathy prudent to be prepared to intubate the patient and provide oxygen/ventilatory
Contraindications: respiratory compromise; cyanosis support if apnea occurs.

Ketamine
Expected observable effect: altered consciousness and decreased aggression Advantages: inexpensive, small volume to inject minimal physical effects at this
Dose and route (cat): ketamine 5-10 mg/kg IM; can be supplemented with dose. This is the author’s sedation of choice for extremely fractious cats.
2 mg/kg IV if needed Drawbacks: injection is painful, poor muscle relaxation
Pain control: mild to moderate Expected duration of effect/recovery: 10-20 minutes
Time to desired effect of sedation: 10-15 minutes Alternative: Alfaxalone
Indications: immobilization of fractious cats; they may still vocalize Notes and comments: can add butorphanol (0.1-0.5 mg/kg) or buprenorphine
Contraindications: use with caution in animals with decreased renal function (0.005-0.02 mg/kg) for added sedation and analgesia
Alfaxalone*
Expected observable effect: heavy sedation to light anesthesia Drawbacks: expensive. Bottle should be discarded within 6 hours of initial use
Dose and route: 2-4 mg/kg IM, 5 mg/kg IM (IM route is for cats and small (package insert).
dogs less than 5 kg) Expected duration of effect/recovery: 5-15 minutes. Recovery is slower after IM
Pain control: minimal at subanesthetic doses administration, and muscle tremors may be seen.
Time to desired effect of sedation: IV: seconds; IM: 5-15 minutes Alternatives: isoflurane, sevoflurane, or other inhalant anesthetic or propofol
Indications: immobilization of fractious animals and induction of general Notes and comments: due to (often marked) respiratory depression, it is prudent
anesthesia to be prepared to intubate the patient and provide oxygen/ventilatory support if
Contraindications: respiratory compromise apnea occurs. Apnea is more likely at higher dosages or in debilitated patients.
Advantages: animals usually tolerate large-volume IM injections well. Works
well for very fractious animals. Good muscle relaxation

*An asterisk indicates the drugs or drug combinations that are appropriate for anesthetic induction.