Midazolam is a water-soluble benzodiazepine used for seizure control, sedation and balanced anesthesia. It is frequently combined with other sedatives or anesthetics to provide muscle relaxation and reduce the amount of accompanying drugs required. Its injectable formulation also supports nonintravenous seizure-rescue applications in selected veterinary patients.
Midazolam acts as a positive allosteric modulator at benzodiazepine-sensitive GABA-A receptor complexes. In the presence of GABA, it increases the frequency of chloride-channel opening and strengthens inhibitory neurotransmission. Reduced neuronal excitability produces anticonvulsant effects, while action in other central pathways contributes to sedation, anxiolysis and muscle relaxation.
2 mg/mL syrup; extrapolated from paediatric use rather than established veterinary efficacy.
Opioid-associated premedication
0.2–0.4 mg/kg
IV, IM
With an appropriate opioid; hydromorphone examples are 0.1 mg/kg IV or 0.2 mg/kg IM.
Status epilepticus
0.07–0.2 mg/kg
IV, IM
Short effect; transition to a monitored infusion if seizures recur.
Status-epilepticus infusion
0.05–0.5 mg/kg/hour
IV
Continuous
IV anaesthetic adjunct
0.1–0.5 mg/kg
IV
Status epilepticus
0.25 mg/kg
IV
Once
Cats
Use / stage
Dose
Route
Schedule
Instructions
Sedation
0.05 mg/kg
IV
Ketamine-associated induction
Reference only
IV
Midazolam 0.3-0.6 mg/kg with ketamine 3 mg/kg IV; additional ketamine 1-2 mg/kg may be used as needed. A combination protocol is required.
Opioid-associated premedication
0.2–0.4 mg/kg
IV, IM
With an appropriate opioid; hydromorphone examples are 0.1 mg/kg IV or 0.2 mg/kg IM.
Status epilepticus
0.07–0.2 mg/kg
IV, IM
Short effect; transition to a monitored infusion if seizures recur.
Status-epilepticus infusion
0.05–0.5 mg/kg/hour
IV
Continuous
IV anaesthetic adjunct
0.1–0.5 mg/kg
IV
Pigs
Use / stage
Dose
Route
Schedule
Instructions
Sedation or anaesthetic adjunct
0.5 mg/kg
IM
Reported upper dose; usually combined with ketamine, not evidence of a lower endpoint.
Horses
Use / stage
Dose
Route
Schedule
Instructions
Neonatal seizures — Loading
0.1–0.2 mg/kg
IV, IM
Foals only. IV delivery over 15-20 minutes; the fixed 5-10 mg example is not a universal dose.
Neonatal seizure infusion
Reference only
IV
Reported guidance states 3 mg/hour IV after loading, but the accompanying 2-6 mL/hour range and nominal 0.5 mg/mL mixture do not define a consistent patient-specific rate. A fixed mg/hour infusion requires a patient-specific delivery plan.
Anaesthetic induction adjunct
Reference only
IV
Midazolam 0.1 mg/kg with ketamine 2.2 mg/kg IV and appropriate sedative premedication; not a stand-alone anaesthetic regimen.
Neonatal seizure example
Reference only
IV
For a 50 kg foal: 2-5 mg IV; CRI example 1-3 mg/hour. This remains a weight-qualified patient example, not a universal fixed foal dose. Rapid IV administration can cause apnoea and hypotension.
Neonatal seizure example
Reference only
IM
For a 50 kg foal: 2-5 mg IM, repeated only to effect; do not infer a general dose from the example weight.
Sheep
Use / stage
Dose
Route
Schedule
Instructions
Short-term sedation
0.5 mg/kg
IV, IM
Rabbits
Use / stage
Dose
Route
Schedule
Instructions
Sedation adjunct
1–2 mg/kg
IM, IV
Preanaesthetic anxiolysis
0.5–5 mg/kg
IM, IV
Titrated IV induction adjunct
0.05–0.5 mg/kg
IV
Preoxygenate and provide intubation/ventilation; administer to effect, especially after fentanyl.
Mice
Use / stage
Dose
Route
Schedule
Instructions
Preanaesthetic anxiolysis
3–5 mg/kg
IM, IV
Sedation adjunct
1–2 mg/kg
IM
Rats
Use / stage
Dose
Route
Schedule
Instructions
Preanaesthetic anxiolysis
3–5 mg/kg
IM, IV
Sedation adjunct
1–2 mg/kg
IM
Gerbils
Use / stage
Dose
Route
Schedule
Instructions
Preanaesthetic anxiolysis
3–5 mg/kg
IM, IV
Sedation adjunct
1–2 mg/kg
IM
Hamsters
Use / stage
Dose
Route
Schedule
Instructions
Preanaesthetic anxiolysis
3–5 mg/kg
IM, IV
Sedation adjunct
1–2 mg/kg
IM
Guinea pigs
Use / stage
Dose
Route
Schedule
Instructions
Preanaesthetic anxiolysis
3–5 mg/kg
IM, IV
Sedation adjunct
1–2 mg/kg
IM
Chinchillas
Use / stage
Dose
Route
Schedule
Instructions
Preanaesthetic anxiolysis
3–5 mg/kg
IM, IV
Sedation adjunct
1–2 mg/kg
IM
Birds
Use / stage
Dose
Route
Schedule
Instructions
Analgesia-associated sedation
1–2 mg/kg
IM, IV
With a suitable analgesic; midazolam itself is not adequate analgesia.
Stress-reduction premedication
1 mg/kg
IM
Higher doses up to 6 mg/kg are described but require species- and procedure-specific titration.
Nayzilam 5 mg/0.1 mL nasal spray Human single-dose nasal product; amount is per 0.1 mL, not per mL. Not automatically interchangeable with a measured veterinary nasal rescue volume.
Give IV doses slowly and monitor respiration and blood pressure.
Acidic pH maintains solubility. Compatible water-soluble anaesthetics may be mixed immediately before administration, but storage compatibility must not be assumed.
The described foal infusion recipe adds 50 mg to 100 mL saline and calls the final concentration 0.5 mg/mL; added drug volume changes the final volume, so do not use this as a verified final concentration.
The equine preoperative range printed as 0.011-0.0.44 mg/kg IV has a malformed upper endpoint and is not repaired by guessing. The 50:50 ketamine/midazolam volume mixture assumes exact concentrations: 1 mL/9.1 kg is described as about 0.28 mg/kg midazolam plus 5.5 mg/kg ketamine; no route is supplied for that mixture entry. Bird combination ketamine 10-30 mg/kg plus midazolam 2-6 mg/kg requires an independently defined administration route and analgesia plan.
