If the oromucosal gel is swallowed it will become ineffective. Therefore feeding the dog or giving it treats within 15 minutes after administration of the gel should be avoided. In case the gel is swallowed the dog can be given another dose if necessary 2 hours after the previous dose.
In extremely nervous, excited or agitated animals, the levels of endogenous catecholamines are often high. The pharmacological response elicited by alpha-2 agonists (e.g. dexmedetomidine) in such animals may be reduced.
The safety of administering dexmedetomidine to puppies younger than 16 weeks and dogs over 17 years of age has not been studied.
The safety of Sileo has not been established during pregnancy and lactation in the target species. Therefore, the use of the product during pregnancy and lactation is not recommended.
Do not use in dogs with severe cardiovascular disorders.
Do not use in dogs with severe systemic disease (graded as ASA III-IV) e.g. end stage renal or liver failure.
Do not use in case of hypersensitivity to the active substance or to any of the excipients.
Do not use in dogs obviously sedated from previous dosing.
The use of other central nervous system depressants is expected to potentiate the effects of dexmedetomidine and therefore an appropriate dose adjustment should be made.
Due to peripheral vasoconstriction, transient paleness of mucous membranes at the application site may be observed. Other commonly observed adverse events in clinical trials were sedation, emesis and urinary incontinence.
Uncommon adverse reactions in clinical trials were anxiety, periorbital oedema, drowsiness and signs of gastroenteritis.
The frequency of adverse reactions is defined using the following convention:
- very common (more than 1 in 10 animals displaying adverse reactions during the course of one treatment)
- common (more than 1 but less than 10 animals in 100 animals)
- uncommon (more than 1 but less than 10 animals in 1,000 animals)
- rare (more than 1 but less than 10 animals in 10,000 animals)
- very rare (less than 1 animal in 10,000 animals, including isolated reports).
Signs of sedation may occur when the dose is exceeded. The level and duration of sedation is dose dependent. If sedation occurs, the dog should be kept warm.
Reduced heart rate may be seen after administration of higher than recommended doses of Sileo gel. Blood pressure decreases slightly below normal levels. Respiration rate can occasionally decrease.
Higher than recommended doses of Sileo gel may also induce a number of other alpha-2 adrenoceptor mediated effects, which include mydriasis, depression of motor and secretory functions of the gastrointestinal tract, temporary AV-blocks, diuresis and hyperglycaemia. A slight decrease in body temperature may be observed.
The effects of dexmedetomidine can be eliminated using a specific antidote, atipamezole (alpha-2 adrenoceptor antagonist). In case of overdose, the appropriate dose of atipamezole calculated in micrograms is 3 times (3X) the dose of administered dexmedetomidine hydrochloride in Sileo gel. Atipamezole (at the concentration of 5 mg/ml) dose in millilitres is one sixteenth (1/16th) of the dose volume of Sileo gel.
In case of accidental ingestion or prolonged mucosal contact, seek medical advice immediately and show the package leaflet or the label to the physician. Do not drive as sedation and changes in blood pressure may occur.
Avoid skin, eye or mucosal contact. Wear impermeable disposable gloves when handling the veterinary medicinal product.
In case of skin contact wash the exposed skin immediately after exposure with large amounts of water and remove contaminated clothes. In case of eye or oromucosal contact, rinse abundantly with fresh water. If symptoms occur, seek the advice of a physician.
People with known hypersensitivity to dexmedetomidine or any of the excipients should avoid contact with the veterinary medicinal product.
Pregnant women should avoid contact with the product. Uterine contractions and decreased foetal blood pressure may occur after systemic exposure to dexmedetomidine.
Advice to the Doctor:
Dexmedetomidine, the active ingredient of Sileo is an alpha-2 adrenoceptor agonist. Symptoms after absorption may involve clinical effects including dose-dependent sedation, respiratory depression, bradycardia, hypotension, a dry mouth, and hyperglycaemia. Ventricular arrhythmias have also been reported. Since effects are dose dependent they are more pronounced in small children than adults.
Respiratory and haemodynamic symptoms should be treated symptomatically. The specific alpha-2 adrenoceptor antagonist, atipamezole, which is approved for use in animals, has been used in humans but only experimentally to antagonize dexmedetomidine-induced effects.