EN - Anglická CZ - Česká SK - Slovenská PL - Polská RO - Rumunská RU - Ruská TR - Turecká UA - Ukrajinská
EN - Anglická
  • CZ - Česká
  • SK - Slovenská
  • PL - Polská
  • RO - Rumunská
  • RU - Ruská
  • TR - Turecká
  • UA - Ukrajinská

ROMETAR 20 mg/ml injection solution

Homepage Products Veterinary products ROMETAR 20 mg/ml injection solution

Xylazinum. Injection product for sedation, analgesia and myorelaxation of animals

type of preparative: Analeptic, anaesthetic, hypnotics
target species animals: Dog, Cat, Goat, Sheep, Horse, Cattle

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Composition - 1 ml:

Active substance:

Xylazinum 20 mg (ut xylazini hydrochloridum 23.31 mg) in 1 ml.

Excipients: sodium chloride, methylparabene, water for injection 


Sedative, analgesic, myorelaxant.  For sedation to examine animals or perform less painful procedures (e.g. to calm animals before transfers, weighing, X-raying, treatment of cloven hooves and removing foreign bodies from the oesophagus of big animals etc.).

For painful procedures in combination with local anaesthetics (e.g. dehorning, treatment of paronychia, caesarotomy). In cattle, Rometar is used alone in higher doses for medium and larger procedures, in other animals it is combined with analgesics, hypnotics, injection anaesthetics and myorelaxants. If used in combination, the doses of xylazine and anaesthetic are reduced.


Late stage of pregnancy, dilation and torsion of stomach, blocked oesophagus. Caution should be taken in patients with blood circulation and breathing disorders, hepatic and renal function impairment.  In dogs and cats, diabetes and diseases accompanied with vomitus.
The withdrawal period for food animals only relates to the use of xylazine, without combinations with other drugs.

Adverse effects:

At intravenous administration, the undesirable effects include a temporary reduction of blood pressure, reduced exchange of oxygen and carbon dioxide with external environment, reduced heart activity, reduced breathing frequency (due to a slow conduction of impulse), suppressed control of body temperature with temperature decrease. In horses and cattle, higher doses reduce tension and motility of the digestive tract.  Uterus contraction is increased in pregnant animals. During xylazine effect, increased salivation, micturition and defecation is observed in cattle and cats (seldom in dogs). Vomitus is observed in dogs and cats during the onset of effect. The level of blood sugar is increased temporarily.

Target species:

Horse, cattle, goat, sheep, dog, cat, deer, roe deer and fallow deer.


According to the size of dose, the method of administration and the animal species, the product has a differently expressed sedative (calming), analgesic (pain-killing), anaesthetic (desensitizing) and myorelaxant (reducing a muscle tone) effect.  However, in heavily stimulated and excited animals the product may induce paradoxical (contrary) reactions. Therefore, the animals should be in a quiet environment before and after the product application, until the onset of effect. Xylazine stimulates intensely the parasympathetic nervous system that controls the entrails. It induces bradycardia (reduced heart activity) with AV blockade and increases the sensitivity of myocardium (heart muscle) to catecholamines, which supports the occurrence of arrhythmias. The blood pressure is increased at the beginning, then hypotension (blood pressure reduction) occurs which is more expressive after intravenous application. Breathing is influenced differently in various species and individuals. Breathing frequency and breathing volume per minute are reduced in dogs and cats. In consequence of suppressed thermoregulation mechanisms, the internal body temperature is decreased.

Pharmacokinetic particulars:

Xylazine resorption is fast, the onset of effect after intramuscular and intravenous administration is observed within 5 – 10 minutes and 1 - 5 minutes, respectively. Xylazine is metabolized in the liver, metabolites are excreted via kidneys. The product is excreted via faeces (70%) and urine (30%).


Posology depends on the animal species, the method of administration and the required intensity of effect. The effect of xylazine may be extended by a repeated administration of 1/3 to 1/2 of initial dose.


Rometar alone is applied in doses of 0.6 - 1 mg/kg b.w. (3-5 ml/100 kg b.w.) slowly i.v. Fast intravenous administration may induce a temporary reduction of blood pressure and excitement. In the time of maximum effect, i.e. 2-5 min. after injection, a different sedation is expressed in individuals. When doses are administered at the upper limit, the muscle relaxation is manifested with unsymmetrical motion and just a short loss of soreness. In unquiet, excited and nervous horses sedation is sometimes insufficient.
The product effect persists for 20-30 minutes and subsides after 60 minutes.
The effect of i.m. administration of xylazine in a dose of 7.5-10 ml/100 kg. b.w. is weak.
In case of painful examination, treatment and surgeries in a standing or lying patient, the product is administered in combination with analgesics, hypnotics, injection and inhalation anaesthetics. Most frequently used combination for short procedures on a lying patient: Xylazine 1.1 mg/kg b.w. slowly i.v., 2-3 min. later ketamine 2.2 mg/kg b.w. quickly i.v. The animal lies down spontaneously in 45 seconds to 3 minutes. The duration of effect is individual, from 4 to 30 minutes. The anaesthesia may be prolonged by administration of 1/3 to 1/2 of initial dose at the moment of first symptoms of awakening.
If combined with chloral hydrate, 3-4 ml of Rometar/100 kg b.w. and 4-6 g of chloralhydrate/100 kg b.w. are applied. To induce a general injection desensitization for short-term procedures or to start inhalation anaesthesia, 0.5-0.8 mg of xylazine/kg b.w. is applied i.v., 3-5 min. later guaifenesin (Guajacuran inj.) 8-10 g/100 kg b.w. is administered quickly and strictly i.v., followed immediately with thiopental (Thiopental VÚAB inj.) 4-6 mg/kg b.w. i.v.


Intramuscular administration is preferable. At i.v. administration, the i.m. dose should be reduced by 1/3 to 1/2 and should be applied slowly. The size of intramuscular dose depends on the required intensity of effect.
Dose I – 0.25 ml/100 kg b.w. i.m.: Sedation for calming and small surgeries in local anaesthesia.
Dose II – 0.5 ml/100 kg b.w. i.m.: Medium sedation, weaker relaxation and analgesia. The patient may already lie down.
Dose III - 1 ml/100 kg b.w. i.m.: Very strong sedation with intense CNS depression, longer muscle relaxation and medium analgesia, suitable for a majority of surgical interventions in a lying patient (supplemented with local anaesthesia in case of need).
Dose IV – 1.5 ml/100 kg b.w. i.m.: Induces the state of general anaesthesia with expressive side effects (suppressed breathing, reduced heart activity, flatulence, salivation). It is used exceptionally.
The sedative effect of Rometar in cattle starts, according to the size of dose and the method of administration, within 5-10 min. after i.m. injection and within 1-3 min. after i.v. application and persists from 30 min. to several hours.
Analgesia and myorelaxation (painlessness and relaxation of muscles) 45 to 90 minutes.

Sheep, goat:

0.05 mg/kg b.w. for sedation, 0.2-0.4 mg/kg b.w. i.m. for general anaesthesia. In goats, higher doses cause a more intense suppression of breathing, deceleration of heart activity and salivation.


The product is ineffective.


For sedation 1-3 mg/kg b.w. (0.05-0.15 ml/1 kg b.w.) i.m. after 24-hour starvation and premedication with atropine 0.05 mg/kg b.w. s.c. or i.m. In old patients, obese patients, patients with a higher weight or an impaired state of health, lower limit doses should be selected. In big breeds of dogs (bandog, basset) flatulence may occur occasionally. In combination with local, general injection and inhalation anaesthetics for painful examination, treatment and surgeries. If combined, the doses of Rometar and used anaesthetic should be reduced to one half or third.


For sedation 1-2 mg per kg. b.w. (0.05-0.1 ml/kg b.w.) s.c. or i.m. (upper limit doses induce depressed breathing) after necessary 24 to 36-hour starvation and premedication with atropine. During the onset of effect, vomitus or emesis occur frequently.
In combination with injection anaesthetics (most frequently with ketamine) to induce general anaesthesia before a majority of surgeries.

European deer:

Xylazine after i.m. application of 1-2 mg/kg b.w. (0.05-0.1 ml/kg b.w.) induces strong sedation within 10-15 minutes after administration. A dose of 3-4 mg/kg b.w. i.m. paralyzes the animals for 40-60 minutes.

Roe deer:

The roe deer is very sensitive to the effect of xylazine. The dose of 0.5-1 mg/kg b.w. (0.025-0.05 ml/kg b.w.) i.m. induces deep sedation, and frequently paralyzation that may be achieved reliably with a dose of 1.5-2 mg/kg b.w. i.m.

Fallow deer:

The European fallow deer manifests a higher resistance to xylazine and should be administered a dose of 6-10 mg/kg b.w. i.m. for paralyzation. Identical dosage may be used for the moufflon.
Route of administration: Subcutaneously (s.c.), intramuscularlu (i.m.) and intravenously (i.v.).

Special precautions for dosage:

In case of overdose and related intense bradypnoea (reduced breathing frequency) or apnoea (respiratory arrest), use xylazine antagonists, i.e. yohimbine in the recommended dose of 0.1 – 0.2 mg per kg b.w. and tolazoline (Divascol Spofa inj.) in a dose of 1.5 mg per kg b.w.

Special precautions:

During the onset of effect the animals should not be disturbed with noise or other stimuli. Flatulence in lying cattle should be prevented by keeping the animal in lying position on the sternum.
During surgeries in lateral or dorsal position, the head should be held in a lower position to prevent  inspiration of salivas. During anaesthesia the animals should not be exposed to low or high temperatures of environment which could act as an additional stress factor. Maintenance of normal body temperature is inevitable mainly in case of long-term desensitization. Vomiting in cats and dogs may be prevented with a 12-hour starvation as a minimum.

Withdrawal period:

No withdrawal period for the cattle and horse meat. No withdrawal period for cow’s milk. Do not use in other species which meat is intended for human consumption.

Special precautions for storage:

Keep out of the reach of children.Store at a temperature not exceeding 25°C, protect from the light.

Shelf life:

2 years, 28 days after the first opening (application).


50 ml

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