Midazolam: veterinary dose and monograph

At a glance

Drug class

Sedative / anaesthetic

Also known as

Versed, Dormicum

Species with doses

Dogs, Cats, Cattle, Horses, Sheep, Pigs, Birds, Rabbits, Ferrets, Guinea pigs, Chinchillas, Rats, Hedgehogs, Sugar gliders and Primates

General dose range

0.1–0.3 mg/kg IM once (premed) or CRI — check the species tables for the indication

Routes

IV, IM

Last reviewed

1 October 2026

Indications

• Co-induction with ketamine / propofol / alfaxalone
• Premedication in paediatric, geriatric or critically ill patients
• Status epilepticus (IV / IM / intranasal)
• Sedation in birds and exotics

Midazolam dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• Co-induction / premed: Papich 5e: 0.1–0.25 mg/kg IV or IM. Plumb’s p.837: 0.2–0.4 mg/kg IV or IM with an opioid (Day 2002); 0.1–0.5 mg/kg IV (Hellyer 2005); 50:50 v/v with ketamine at 1 mL per 9.1 kg (≈0.28 mg/kg midazolam + 5.5 mg/kg ketamine). Can cause excitement if given alone to healthy dogs. Reverse with flumazenil.
• Status epilepticus: Plumb’s p.837: 0.25 mg/kg IV (Knipe 2006); 0.2–0.4 mg/kg IV or IM, may repeat once — not per rectum (Hopper 2006); 0.07–0.2 mg/kg IV or IM, then CRI 0.05–0.5 mg/kg/h if seizures recur (Thomas 2010). Papich 5e: 0.1–0.2 mg/kg IV, or 0.2 mg/kg intranasally (5 mg/mL); CRI 0.1–0.3 mg/kg/h.

Cats

• Co-induction / premed: Plumb’s p.837: 0.05–0.5 mg/kg, 0.3 mg/kg most effective mixed with ketamine for intubation (Reed 2002); 0.2–0.4 mg/kg IV or IM with an opioid. Papich 5e: sedation 0.05 mg/kg IV; induction 0.3–0.6 mg/kg IV with ketamine 3 mg/kg.

Cattle

• Calves — anaesthetic induction (with xylazine + ketamine): Plumb’s 10e p.883 (extra-label): calves — induced general anaesthesia with xylazine 0.05 mg/kg IV followed by ketamine 2 mg/kg and midazolam 0.1 mg/kg IV, which allows endotracheal intubation. This is the only cattle dose in Plumb’s 10e and applies to calves within that protocol; Papich 5e lists sheep only. Obtain a FARAD withdrawal.

Horses

• Anaesthetic adjunct (with ketamine): Papich 5e: 0.1 mg/kg IV given with ketamine 2.2 mg/kg or other anaesthetics (e.g. xylazine). Reverse with flumazenil.
• Neonatal foal seizures: Papich 5e: 0.1–0.2 mg/kg (5–10 mg per foal) IV over 15–20 min or IM, then about 3 mg/h CRI. Plumb’s p.837: 2–5 mg TOTAL IV (or IM) for a 50 kg foal, repeated to effect; CRI 1–3 mg/h for a 50 kg foal (Bentz 2006). Rapid IV can cause apnoea and hypotension. (The previous 0.1–0.2 mg/kg/h CRI was several-fold too high.) (Plumb’s 2–5 mg per 50 kg foal = 0.04–0.1 mg/kg; Papich 0.1–0.2 mg/kg.)

Sheep

• Short-term sedation: Papich 5e: sheep 0.5 mg/kg IV or IM for short-term sedation. Extra-label in a food animal — obtain a FARAD withdrawal.

Pigs

• Miniature/pet pig — sedation / premed: Carpenter Exotic Animal Formulary 6th ed, Table 12-4 (p.665–666): miniature pigs 0.1–0.5 mg/kg IM or IV; 0.2–0.4 mg/kg intranasal. Widely combined with ketamine/azaperone/dexmedetomidine. Reverse with flumazenil. Papich 5e: pigs up to 0.5 mg/kg IM, usually with ketamine.

Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

• Calves — anaesthetic induction (with xylazine + ketamine): Plumb’s 10e p.883 (extra-label): calves — induced general anaesthesia with xylazine 0.05 mg/kg IV followed by ketamine 2 mg/kg and midazolam 0.1 mg/kg IV, which allows endotracheal intubation. This is the only cattle dose in Plumb’s 10e and applies to calves within that protocol; Papich 5e lists sheep only. Obtain a FARAD withdrawal.

Birds

• Sedation / premedication: Plumb’s p.837: 1–2 mg/kg IM or IV with an analgesic (Clyde & Paul-Murphy 2000); 1 mg/kg IM premed for anxious birds (up to 6 mg/kg gives heavy sedation); with ketamine 10–30 mg/kg, midazolam 2–6 mg/kg (Morrisey 2010). Reverse with flumazenil 0.1 mg/kg.

Rabbits

• Sedation / premedication: Plumb’s p.837: rabbits 1–2 mg/kg IM or IV (Ivey & Morrisey 2000); premedication 0.5–5 mg/kg IM or IV; IV induction adjunct 0.05–0.5 mg/kg to effect with pre-oxygenation and intubation (Vella 2009). Reverse with flumazenil.

Ferrets

• Sedation / premedication: Carpenter's 6th ed (Ferret restraint/anaesthetic table): 0.25–0.3 mg/kg SC/IM, or 0.25–0.5 mg/kg SC/IM/IV — mild sedation/premedication. Combos: midazolam 0.2 mg/kg + butorphanol 0.2 mg/kg IM for minor procedures; or with ketamine 5–10 mg/kg IV for induction. Reversible with flumazenil.

Guinea pigs

• Sedation / premedication: Plumb’s p.837 (Adamcak & Otten 2000): hamsters, gerbils, mice, rats, guinea pigs and chinchillas 1–2 mg/kg IM; rodent premedication 3–5 mg/kg IM or IV.

Chinchillas

• Sedation / premedication: Plumb’s p.837 (Adamcak & Otten 2000): 1–2 mg/kg IM; rodent premedication 3–5 mg/kg IM or IV.

Rats

• Sedation / premedication: Plumb’s p.837 (Adamcak & Otten 2000): 1–2 mg/kg IM; rodent premedication 3–5 mg/kg IM or IV; injectable anaesthesia midazolam 5 mg/kg + ketamine 100 mg/kg + buprenorphine 0.05 mg/kg IP (Bennett 2009).

Hedgehogs

• Sedation / anaesthesia (with ketamine): Carpenter Exotic Animal Formulary 6th ed, Table 8-4 (p.516): hedgehogs — ketamine 30 mg/kg + midazolam 1 mg/kg IM; also part of midazolam-butorphanol ± ketamine sedation protocols. Preferred over diazepam for IM use. Reverse with flumazenil.

Sugar gliders

• Sedation / premedication: Carpenter Exotic Animal Formulary 6th ed, Table 7-3 (p.500): sugar gliders 0.1–0.5 mg/kg SC/IM or intranasal. Combine with ketamine/butorphanol; give preemptively to reduce postsurgical self-mutilation. Reverse with flumazenil.

Primates

• Sedation / premedication (monkeys): Carpenter Exotic Animal Formulary 6th ed, Table 13-4 (p.697): monkeys 0.05–0.1 mg/kg IM/slow IV; brown lemurs/prosimians 0.1–0.3 mg/kg IM/IV; with ketamine helps prevent seizures in lemurs. Reversible with flumazenil.

Contraindications

Sole sedative in healthy excitable adults (can cause paradoxical excitation). Severe hepatic impairment (prolonged effect). Reverse with flumazenil if needed.

Adverse effects

• Paradoxical excitation / dysphoria when used alone in healthy animals
• Mild respiratory depression (additive with opioids)
• Minimal cardiovascular effect (a benzodiazepine advantage)

Drug interactions

• Inhalational anaesthetics: midazolam DECREASES the dose required
• Thiopental: midazolam decreases the dose required
• Azole antifungals (ketoconazole, itraconazole, fluconazole): may INCREASE midazolam levels
• Calcium-channel blockers (diltiazem, verapamil): may increase midazolam levels
• Macrolides (erythromycin, clarithromycin): may increase midazolam levels
• Cimetidine: may increase midazolam levels
• Other CNS depressants: increased risk of respiratory depression
• Opiates: may increase the hypnotic effect of midazolam; hypotension has been reported with meperidine (pethidine)
• Phenobarbital: may DECREASE peak levels and AUC of midazolam
• Rifampin: may decrease peak levels and AUC of midazolam
• Propofol: synergistic — midazolam plasma concentrations may rise by up to 20% (Plumb's propofol monograph)

Pregnancy and lactation

Crosses the placenta; reserve for when benefits outweigh risks. Reversible with flumazenil.

Toxicity and overdose

Plumb's p.836: very limited information. The IV LD50 in mice is reported as 86 mg/kg. Accidental overdoses should be managed supportively, as for diazepam. FLUMAZENIL can antagonise midazolam, but because midazolam is short-acting and flumazenil is expensive, supportive therapy is usually more appropriate for all but the largest overdoses. The practical hazard is respiratory depression, especially when stacked with opioids or other CNS depressants.

Clinical pearls

• Reliable IM absorption and non-irritant — the benzodiazepine of choice when IV access is difficult
• Best combined with an opioid or dissociative — alone in healthy adults it can cause dysphoria, not sedation
• Excellent cardiovascular stability makes it ideal for sick / cardiac patients

Mechanism of action

Plumb's p.836: benzodiazepine. Depresses the subcortical CNS — primarily limbic, thalamic and hypothalamic levels — producing anxiolysis, sedation, skeletal muscle relaxation and anticonvulsant activity. The exact mechanism is unknown; postulated contributions are antagonism of serotonin, increased release and/or facilitation of GABA activity, and diminished release or turnover of acetylcholine in the CNS. Benzodiazepine-specific receptors are found in mammalian brain, kidney, liver, lung and heart, and are absent from white matter in every species studied. Midazolam's distinguishing property is its solubility: water-soluble in the vial but LIPID-soluble at body pH, which gives a very rapid onset after injection, and it has roughly TWICE the benzodiazepine-receptor affinity of diazepam.

Formulations and products

• Midazolam 5 mg/mL injection
• Midazolam 1 mg/mL injection

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other sedatives and anaesthetics

• Guaifenesin (GGE)
• Isoflurane
• Ketamine HCl
• Medetomidine
• Pentobarbital (Pentobarbitone)
• Phenobarbital
• Propofol
• Romifidine

Frequently asked questions