Romifidine: veterinary dose and monograph

At a glance

Drug class

Sedative / anaesthetic

Also known as

Sedivet, Romifidine HCl

Species with doses

Dogs, Cats, Cattle and Horses

General dose range

0.04–0.12 mg/kg IV single dose (reversible) — check the species tables for the indication

Routes

IV, IM, Epidural

Last reviewed

1 October 2026

Indications

• Standing sedation in horses for clinical/diagnostic and minor procedures (less ataxia)
• Premedication / component of balanced anaesthesia (horses)
• Sedation/restraint with reduced head-lowering for dental/standing work
• Sedation in cattle (off-label) and, less commonly, dogs

Romifidine 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

• Sedation / pre-anaesthetic: Plumb’s p.1048 (Romydis label): 40–120 µg/kg IV, IM or SC — IV sedation within about 5 min; IM/SC onset about 30 min and shallower. Induce anaesthesia about 10 min after IV (10–15 min after IM/SC). Reverse with atipamezole (200 µg/kg IM reverses 120 µg/kg). Papich 5e: small-animal doses not established. (40–120 µg/kg = 0.04–0.12 mg/kg.)
• Analgesic adjunct (low dose): Plumb’s p.1048 (Lamont & Tranquilli 2002): 10–20 µg/kg IM or SC in exercise-tolerant dogs without heart disease; may combine with an anticholinergic.

Cats

• Sedation / pre-anaesthetic: Plumb’s p.1048 (Romydis label): 200–400 µg/kg IV or IM; 200 µg/kg IM sedates in about 10 min for about 60 min. Pre-anaesthetic: 200 µg/kg IM 10–15 min before ketamine 10 mg/kg IM gives up to 30 min surgical anaesthesia (400 µg/kg extends it). Reverse with atipamezole IM (400 µg/kg reverses 400 µg/kg). (200–400 µg/kg = 0.2–0.4 mg/kg.)
• Analgesic adjunct (low dose): Plumb’s p.1048 (Lamont & Tranquilli 2002): 20–40 µg/kg IM or IV in healthy cats without heart disease.

Cattle

• Epidural analgesia (flank laparotomy): Plumb’s p.1048 (Anderson 2006): romifidine 50 µg/kg plus morphine 0.1 mg/kg epidurally; analgesia up to 12 h. Not FDA-approved in food animals — obtain a FARAD withdrawal. Plumb’s 10e p.1130 gives the same 50 µg/kg + morphine 0.1 mg/kg epidural (analgesia 12 h maximum) and notes epidural romifidine alone at 30–50 µg/kg in dairy cows caused dose-dependent sedation (deep at 50 µg/kg). No systemic sedative dose for cattle in Papich 5e or Plumb’s 10e.

Horses

• Standing sedation: Papich 5e and Plumb’s p.1048 (Sedivet label): 40–120 µg/kg IV slowly once (0.4–1.2 mL per 100 kg of 10 mg/mL); sedation is dose-dependent, onset 0.5–5 min, subsiding over 2–4 h; analgesia is shorter than sedation. Often combined with butorphanol. (40–120 µg/kg = 0.04–0.12 mg/kg.)
• Pre-anaesthetic: Papich 5e and Plumb’s p.1048 (label): 100 µg/kg as a slow single IV injection; induce once maximal sedation is reached. Romifidine is anaesthetic-sparing — reduce induction doses. (100 µg/kg = 0.1 mg/kg.)

Buffalo

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

• Epidural analgesia (flank laparotomy): Plumb’s p.1048 (Anderson 2006): romifidine 50 µg/kg plus morphine 0.1 mg/kg epidurally; analgesia up to 12 h. Not FDA-approved in food animals — obtain a FARAD withdrawal. Plumb’s 10e p.1130 gives the same 50 µg/kg + morphine 0.1 mg/kg epidural (analgesia 12 h maximum) and notes epidural romifidine alone at 30–50 µg/kg in dairy cows caused dose-dependent sedation (deep at 50 µg/kg). No systemic sedative dose for cattle in Papich 5e or Plumb’s 10e.

Contraindications

Significant cardiovascular disease (bradyarrhythmia/AV block), shock/hypovolaemia, and late pregnancy (uterine/fetal effects). Respiratory compromise. Use reduced doses in debilitated animals. Concurrent IV potentiated sulfonamides in horses (alpha-2 agonist + IV TMP-sulfa has caused fatal arrhythmias). Known hypersensitivity.

Species-specific warnings

Cattle: Cattle are highly alpha-2 sensitive — use much lower doses than horses; off-label.

Horses: Avoid concurrent IV trimethoprim-sulfonamide (alpha-2 + IV TMP-sulfa has caused fatal arrhythmias in horses).

Adverse effects

• Bradycardia and AV block; initial hypertension then hypotension
• Reduced cardiac output, ataxia (less than xylazine/detomidine), sweating
• Diuresis, hyperglycaemia, reduced GI motility
• Muscle relaxation; penile prolapse in stallions (transient)

Drug interactions

• Other sedatives/anaesthetics/opioids: additive sedation and cardiorespiratory depression (often combined deliberately, e.g. with butorphanol)
• IV potentiated sulfonamides (TMP-sulfa) in horses: fatal arrhythmias reported with alpha-2 agonists — avoid concurrent IV use
• Atipamezole: reversal agent
• Anticholinergics: variable (may worsen hypertension) — use judiciously for bradycardia

Pregnancy and lactation

Avoid in late pregnancy (alpha-2 effects on uterine tone/fetus).

Monitoring

• Heart rate/rhythm (bradycardia/AV block), mucous membranes, blood pressure
• Depth/duration of sedation; respiratory rate
• Avoid concurrent IV TMP-sulfa in horses
• Recovery quality (reverse with atipamezole if needed)

Toxicity and overdose

Overdose deepens the alpha-2 cardiovascular effects — profound bradycardia/AV block, hypotension, marked CNS and respiratory depression. Generally survivable with reversal because the effect is specifically antagonisable.

Management: Antidote: ATIPAMEZOLE reverses sedation and cardiovascular effects (dose per product/clinical judgement). Support ventilation/oxygenation; treat clinically significant bradycardia per anaesthetic judgement; IV fluids for hypotension after the vasoconstrictive phase.

Clinical pearls

• The alpha-2 of choice for many standing equine procedures — similar sedation to xylazine/detomidine but with LESS ataxia and head-lowering (the horse stays steadier/head higher)
• Longer-acting than xylazine; commonly combined with butorphanol for standing work
• Class cardiovascular effects apply (bradycardia, AV block) — and atipamezole reverses it
• In horses, do NOT give IV potentiated sulfonamides concurrently with alpha-2 agonists (fatal arrhythmias reported)

Mechanism of action

A selective alpha-2 adrenoceptor agonist: central (brainstem/locus coeruleus) alpha-2 stimulation reduces noradrenaline release → sedation and analgesia, while peripheral vascular alpha-2 receptors cause initial vasoconstriction (transient hypertension with reflex bradycardia) followed by reduced sympathetic tone. Its receptor/pharmacokinetic profile yields sedation with comparatively less ataxia and head-lowering than other equine alpha-2 agonists.

Formulations and products

• Injection 10 mg/mL (Sedivet)
• Sedivet (Boehringer Ingelheim) — 10 mg/mL, Injection

Storage

Injection: 15–30 °C, protect from light; do not freeze.

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

• Midazolam
• Pentobarbital (Pentobarbitone)
• Phenobarbital
• Propofol
• Sevoflurane
• Thiopental Sodium
• Tiletamine–Zolazepam
• Trazodone

Frequently asked questions