Plus-Hex CLINICAL
Introduction
Many dogs find a visit to the veterinary clinic stressful and associate the environment with negative experiences. The clinic may be a new environment or already associated with unpleasant experiences and an inability to avoid a potentially threatening situation. In a database of 26,555 responses, 41 % of companion dogs displayed mild to moderate fearful behaviour when examined by a veterinary surgeon, and 14 % exhibited severe or extreme fear, according to their guardians [ 1 ].
Veterinary practice guidelines, such as those provided by Hammerle et al. [ 2 ] and Yin [ 3 ], increasingly emphasise the need to strive to create a low-fear and low-stress environment for patients, staff and owners. Many physiological and behavioural signs of pain, discomfort or problematic behaviour are harder to distinguish when the dog experiences stress [ 4 ]. If the dog is stressed during an examination, difficulty confirming a correct diagnosis may result in a lower quality of subsequent treatment [ 5, 6 ].
A clinical examination normally encompasses primary objective measurements such as respiratory rate( RR), blood pressure, body temperature and heart rate( HR). All of these are prone to distortion by short-term stress reactions [ 7 ]. During stress, the sympathetic nervous system is activated to facilitate the‘ four Fs’ – fawn, freeze, fight or flight responses – and this affects several physiological parameters [ 8 ]. For instance, Bragg et al. [ 7 ] found elevated systolic blood pressure, increased HR, elevated body temperature and panting in dogs examined at the clinic versus at home. Blood pressure( systolic, diastolic and median arterial pressure) was significantly higher in greyhounds when measured in a hospital setting than when measured at home by either their guardian or an investigator [ 9 ].
Dogs that do not allow treatment are challenging and may need to be sedated in order to be examined. Stress in in-patient dogs can also lead to long-term effects such as poorer wound healing, increased susceptibility to infections and gastrointestinal problems [ 10 ]. Dogs under stress also pose a risk of injury to themselves or their human counterparts from displays of spontaneous aggression.
Furthermore, early-life events have a large impact on a dog ' s fear and anxiety in later life. Even a single visit to the veterinary clinic can have a dramatic impact on a pet ' s long-term behavioural wellbeing. For this reason, ensuring a low-stress situation at each visit reduces the risk of having a stressed dog at the following visit. The animal ' s stress-related negative experience can also affect the client ' s willingness to return to the clinic [ 11 ], which will, in turn, affect treatment continuity.
Several studies have identified factors that can be addressed in the clinic to minimise stress [ 12, 13 ]. The patient ' s basic behavioural needs can be better understood and met by integrating basic behavioural management into care [ 2 ]. Some procedures can be adjusted to lower the patient ' s stress levels, for example, by changing the way the animal is physically approached and greeted. Specific elements of the visit that increase the stress response can be identified and modified. Using an examination table that results in a high stress response could contribute to a negative experience, which could then cause increased stress at future clinic visits [ 11 ]. Therefore, it can be preferable to examine some dogs on the floor or, in exceptional cases, outdoors. Altering the physical environment, for example, by addressing auditory and olfactory stimuli, can make a big difference.
Dog owners or veterinary care professionals could potentially prepare the dog ahead of an examination by administering a low-risk stress-lowering agent in the form of a pre-visit pharmaceutical( PVP) or a nutritional supplement. PVPs are drugs with sedative and anxiolytic properties that can be administered in connection with veterinary visits; examples are dexmedetomidine, alprazolam, clonidine, gabapentin, trazodone and imepitoin. Lately, there has been an increase in the number of supplements and supplementary feeds marketed as having an effect in alleviating stress and anxiety in animals [ 14 ]. Supplementary feeds are sometimes used in veterinary care, but so far there are not enough studies to prove their effectiveness [ 15 ].
Two commonly used products were examined in the current study: the dexmedetomidine oromucosal gel Sileo, and the supplementary feed Aptus Relax.
Sileo dexmedetomidine oromucosal gel
Sileo oromucosal gel( Orion Pharma Animal Health)( hereafter referred to as DEXO) is a prescription drug containing the active substance dexmedetomidine. Indicated for sound sensitivity, DEXO is often given before minor procedures, and provides potent reversible sedation.
Dexmedetomidine is a selective alpha-2 adrenoceptor agonist. Alpha-2 agonists inhibit the activation of the sympathetic nervous system by reducing norepinephrine( noradrenaline) [ 16 ]. The levels of the catecholamines norepinephrine and adrenaline are often high when an animal is very nervous, stressed or anxious, which can reduce the pharmacological effect of alpha-2 agonists [ 17 ]. At a sufficiently large dose, dexmedetomidine can achieve general anaesthesia [ 18 ]. Dexmedetomidine easily crosses the blood – brain barrier and is rapidly distributed throughout the body.
The side effects observed are decreased HR, temporary atrioventricular block, initially elevated blood pressure that then drops to a normal or below-normal level, a sporadically decreased RR, decreased activity in the gastrointestinal tract and a slight decrease in body temperature [ 17 ].
Volume 41( 4) • August 2026
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