Ankara University Faculty of Veterinary Medicine, Department of Pharmacology and Toxicology, ANKARA.
Akdeniz University Faculty of Veterinary Medicine, Department of Pharmacology and Toxicology, BURDUR.
- Ali BİLGİLİ
- Levent ALTINTAŞ
- Fatma ŞAHİNDOKUYUCU
Within the scope of this review, information about the use and effects of sedative and immobilising drugs applied in cats and dogs
and for this purpose the drugs commonly used in cats and dogs were tabulated.
INTRODUCTION
Veterinarians use tranquilisers and immobilisers at a higher rate than estimated in clinical practice (12). Sedatives are used in many applications in cats and dogs,
The use of tranquilisers and general anaesthetics greatly reduces the stress and pain of the animal. Diagnostic procedures such as radiography, ultrasound and biopsy can be performed in sedated animals.
more easily realised. In addition, these applications It is also ensured that the personnel work comfortably (24). In the light of this information, in this article, in cats and dogs substances used as sedatives and immobilisers and It is aimed to give information about doses.
Sedation and Immobilisation of Animals Points to be considered while performing the prayer
Decision on sedative medication for cats and dogs when some animal-specific conditions (pregnancy, etc.) are considered to take into account the appropriate equipment and tools
is important. In particular, it is important to ensure that the animal whether the patient has been given sedatives and anaesthesia practices, food and fluid consumption, medication and
information about the last food eaten from the animal owner must be collected. If the owner of the animal immobilised for a long period of time during sedative medication
the dose of the medication used should be reduced. Manual intervention to painful animals is very difficult. Because the animal reacts to protect itself. Sedatives
the animal's reactions to these interventions they prevent it. The animal owner is asked to provide the animal's previous when informed about the exercise status of the animal
is mobile or runs tirelessly after a ball "the animal's cardiovascular system is normal" you could say. However, this is not the case for cats.
Physical conditions of cats may cause mistakes (28). Age and breed of the animal are also important in drug selection. is one of the factors. Most young animals (less than 12 weeks old cats or dogs) or elderly animals in need of care cannot metabolise drugs as well as healthy animals. This means that animals usually have central nervous system (CNS) are more sensitive to the effects of suppressors; therefore The dose of CNS suppressors in older animals is not expected to be as high as in healthy animals. reducing the dose given to animals by 15-30 per cent required (3).
With sedation or chemical suppression Facilitated Applications
1. Inspection (17),
2. Minor surgical interventions,
3. Wound care (13),
4. Routine maintenance operations: Examination or radiography When a sedative is used for sedation, the animal is still sedated. blood and urine samples can be taken on the go or nail clipping
additional applications such as this can be performed (17). Low doses given oral examination of the animal with propofol, sutures and external examination of the ear and eye
is provided (11).
5. Bathing and nail trimming (14, 17),
6. Drains, bandages, collars, intravenous (DI)
and excretory catheters and cage rest. increase tolerance (13, 17).
Duration of the Sedative Effect
Veterinarians recommend that cats and dogs be sedated while waiting for them to quickly recover from their condition. They prefer a long and sustained low-level state. If a continuous low level of stabilisation is to be established the route of administration as well as the characteristics of the drug to be used is important. In this case, long-acting drugs are preferred. For example, asepromazine applications provide 6-12 hours of sedation. state, while in some animals a longer lasting effect may also occur. The duration of telazol and ketamine depends on the dose.
It lasts 2-4 hours. Alpha-2 adrenergic receptor stimulants are more have long lasting effects. Benzodiazepines (BZ) and The efficacy of butorphanol lasts for 1-2 hours (17).
Characteristics of an Ideal Immobilizing Drug It should be effective in small quantities, durable, rapidly absorbed from the systemic circulation, produce an immobilizing effect in a short time and have a sufficiently long duration of action. The safety margin should be wide (at least 3-fold), should not cause significant side effects in pregnant animals, should be excreted from the body in a short time, should not c a u s e permanent damage to animals, should not cause irritating effects on tissues, and should have little or no effect on the cardiovascular and respiratory systems. The onset and withdrawal periods of anesthesia should be uneventful, comfortable and calm, and should be safe for the personnel administering it. An ideal immobilizing drug should reduce the animal's fear, stress and pain, cut off its interest in the environment and have a special antidote against the undesirable effects of the drug (6, 8, 25).Drugs Used and Their Classification Medicines used as sedatives and chemical inactivators are divided into 3 groups:
Sleep Inducers and Sedatives
Sleep-inducing and sedative drugs cause sedation and sleep in cats and dogs by moderately or moderately depressing the CNS. Drugs in this class can be used subcutaneously (DA), intramuscularly (IM), intravenously and orally in all animal species, especially cats and dogs (4, 18). This group includes alpha-2 adrenergic receptor stimulants, BZs, barbiturates and propofol (17).
Barbiturates
Barbiturates were among the first drugs used to suppress the CNS. Today, BZs have replaced barbiturates (9). Phenobarbital and barbital are used as sedatives and sleep inducers in cats and dogs. barbiturates (Table 1) (4).
Phenobarbital
In cats and dogs, phenobarbital is usually used orally as a sedative and sleep-inducer, the DI route is not preferred, and it is also used to immobilize aggressive cats and dogs.
It is also used to make it. Excessive during use causes saliva secretion. Therefore, an anticholinergic drug such as atropine should be given before use (4, 24, 29).
Barbital
Barbital was the first barbiturate derivative used for sedative and sleep-inducing purposes. Its duration of action is slightly shorter than phenobarbital. DI applications are not preferred because it causes medullary paralysis (17, 24).
Benzodiazepines
BZs potentiate the effects of many anesthetics and
narcotic painkillers. They are very safe drugs and generally
have few respiratory and cardiovascular effects.
Combinations of ketamine and diazepam, midazolam and
narcotic analgesics, tiletamine and zolazepam are frequently
used. Members of this group are diazepam and midazolam
(Table 2) (1, 9, 13).
Diazepam
Diazepam can be used alone or in combination with
other drugs. It is teratogenic; therefore, it should not be used
in pregnant cats and dogs (5, 18). It is also not suitable as a
sedative in old and very young cats and dogs (14, 15).
Diazepam is not preferred as a sedative and
tranquilizer because it can cause stimulation and unpleasant
behavior in cats. The side effects of diazepam are reversed
using flumazeril. Flumazeril is a specific antagonist of
diazepam receptors (25, 30).
Midazolam
Midazolam has similar efficacy to diazepam, but with
a shorter duration of action. The drug has an efficacy 3-4
times stronger than diazepam and 20 times stronger than
thiopental. Midazolam shows all the characteristic features of
BZs (4, 5, 14, 26). The drug can be administered to animals
by all routes. It is also used in combination with other drugs
such as ketamine and thiobarbiturates (9, 16).
1.3. Alpha-2 Adrenergic Receptor Stimulants
Drugs known as alpha-2 adrenergic receptor stimulators are in the class of analgesics and are widely used in veterinary medicine as sedatives and immobilizers (27).
1.3.1. Thiazines
They act on presynaptic and postsynaptic alpha-2 adrenergic receptors in the central and peripheral nervous system. Alpha-2 adrenergic receptors in the CNS are involved in the perception of pain, such as the ability to understand, excitability, insomnia, regulation of endocrine and cardiovascular system functions are responsible for the functions of the sympathetic nervous system. Drugs in this group also have such effects. In cats and dogs, they sometimes cause a stimulant effect instead of a
sedative effect; therefore, they should be used in combination with other drugs (9, 24).
Barbital Orally150-1000
mg/dog
100-300 mg/cat
Sleep
fertility
Among thiazine derivatives, xylazine and medetomidine are
used in cats and dogs (30).
1.3.1.1. Xylazine
Xylazine is an alpha-2 adrenergic receptor stimulant that was first used in veterinary medicine for pain relief and sedative purposes (14, 15, 20, 23, 30). It provides good sedation when given to cats and dogs at a dose of 1-3 mg/kg via the PI route and shows its effect within 3-6 minutes. When xylazine is used via DI route, the dose should be reduced. It shows its effect i n 1-2 minutes when administered in this way (5). The major side effect of xylazine in cats and dogs is vomiting (14, 15, 18, 20, 23). Its effects on the cardiovascular system are dose-dependent and cardiac depression and hypotension are observed at doses higher than 3 mg/kg. In cases where very high doses are used, respiratory system depression is observed in addition to cardiovascular system (14, 18, 23). It also causes unconsciousness (not responding to external stimuli) and prolonged recovery from anesthesia. Therefore, its use in high doses is not recommended. The undesirable effects of xylazine can be prevented with anticholinergics such as atropine; however, sometimes the desired results cannot be obtained from the use of atropine and hypotension with tachycardia occurs (14). The dose of xylazine is reduced when used in combination with other sedative drugs, tranquilizers, opioids, or general anesthetics. Xylazine should not be used in animals with renal, hepatic, respiratory or cardiac insufficiency and in pregnant animals (23, 26). The recommended doses of xylazine in cats and dogs are 0.25-0.50 mg/kg by DI route, and 0.5-1.0 mg/kg by KI route (23).
1.3.1.2. Medetomidine
Medetomidine is an alpha-2 adrenergic receptor stimulant that has recently been used in cats and dogs (9). It is 40 times more potent than xylazine (7, 31). Medetomidine causes a profound sedation when administered to dogs at a dose of 40 μg/kg CI (14, 23, 32) and does not cause much change in blood pressure when used at this dose. Repeated administration of the drug causes respiratory irregularity. Vomiting occurs in approximately 20% of dogs given medetomidine. The dose of medetomidine is based on body surface area rather than body weight. Therefore, drug doses in small animals are higher than doses in large animals (14, 23). Medetomidine provides maximal sedation in mediumsized and calm dogs at a dose of 20 μg/kg by the DI route. The time to reach maximum sedation is 15-20 minutes with KI injections. The drug has recently begun to replace xylazine in cats. Administration of the drug at 80 μg/kg bw produces a good sedation equivalent to xylazine at 3 mg/kg bw. The maximum effect occurs within 10-15 minutes. The time to awakening is also dose-dependent, but at a dose of 80 μg/kg the clinical effect of the drug is over in about 1 hour. It takes 2.5-3 hours for the animal to fully recover. Side effects of the drug are similar to xylazine. Bradycardia in cats is corrected with atropine or glycopyrrolate (15, 32). The effects of the drug are reversed with atipamezole (6, 7).
Medetomidine causes hypoinsulinemia and hyperglycemia; therefore it should not be used in dogs and cats with diabetes. Also shock, heat stress, exhaustion, It should also not be used in animals with liver, kidney,
cardiovascular and respiratory system failure (23).
1.4. Propofol
Propofol is a rapidly metabolized, non-barbiturate
sedative-sleep-inducing drug used for the induction and
maintenance of general anesthesia. In dogs and cats, it is
administered by the IV route for sedation and anesthetic
effect (1, 11, 16). T h e d r u g i s u s e d
i n patients with renal and hepatic
can also be used in animals (1, 11).
2.Tranquilizers and Neuroleptics
Tranquilizers are used to make sedation safe and
prolong its duration, to reduce fear and stress during transport
and to prevent complications caused by this stress.
2.1. Phenothiazine Derivatives
Asepromazine is the most commonly used drug in
this group. It is even recommended as the only drug for
sedation and premedication of dogs. Other phenothiazine
derivatives such as propiopromazine, promazine,
promethazine, trimeprazine and chlorpromazine can also be
used for sedation (10, 13).
2.1.1. Asepromazine
Asepromazine is one of the drugs commonly used as
a sedative in dogs and cats (9, 20, 30). The response of dogs
to asepromazine varies according to body temperature,
physical condition and nutritional status of the animal. Large
breeds such as Newfoundland are highly sensitive to these
drugs and even doses of 0.03 mg/kg cause sedation. Mediumsized dog breeds such as Greyhounds are also sensitive to
these drugs. These animals may develop hypotension as well
as sedation. Small breeds such as terriers are very resistant to
these drugs and may not be sedated even when given in large
doses. In boxer breeds, by the BM route
Rapid sedation even with 0.02 mg/kg dose of asepromazine
takes shape.
In dogs, injections of 0.03-0.05 mg/kg bw are usually
sufficient to induce sedation. Even if these doses are
exceeded, no significant increase in sedative efficacy is
observed. Asepromazine and atropine can be mixed in the
same syringe and administered via DI route (14).
In cats, asepromazine is used as a sedative at a dose
of 0.03-0.05 mg/kg via the SI route (15).
3. Cyclohexylamines
Cyclohexylamines used in cats and dogs are ketamine
and tiletamine (Table 3). These two drugs are widely used in
mammals (25, 30). They have great advantages in terms of
capturing and safely holding domestic animals of all species,
especially wild and feral animals, inducing anesthesia easily
and without any drawbacks, and providing versatile positive
interactions with similar drugs (26).
3.1. Ketamine
Ketamine was initially introduced into veterinary practice as a cataleptoid anesthetic for cats. In recent years it has been used in all animals for chemical fixation, immobilization, preanesthetic medication, induction of anesthesia and general anesthesia.
However, the drug also has a strong analgesic effect (26, 27). It is used in doses of 2-50 mg/kg between species. Doses of 10-30 mg/kg are sufficient for the capture of wild animals (25). Immobilization with ketamine alone usually r e s u l t s i n excessive salivation, muscle stiffness and convulsions. Xylazine is very effective to prevent muscle rigidity caused by ketamine (18, 28). Ketamine is used safely in dogs as well as cats. In cases where animals need to be restrained, it is sufficient to administer xylazine at a dose of 2.2 mg/kg via the SI route and ketamine at a dose of 11 mg/kg via the same route 10 minutes later. For the same purpose, ketamine (22 mg/kg) +asepromazine (1.1 mg/kg) can also be used together (18). The effect of ketamine is reversed with doxapram. Muscle contractions and moderate tonic contractions that may occur are controlled with short-acting barbiturates, diazepam and midazolam (25).
3.2. Tiletamine
Tiletamine is 3-4 times more potent than ketamine.
When used alone, it shows pharmacologic effects similar to
ketamine, but its duration of action is longer. It is generally
used in combination with zolazepam (18, 21, 22, 25, 30).
Zolethyl has a wide range of uses in most animal
species. It is used for immobilization, introduction and
maintenance of anesthesia in cats and dogs (22, 25). The
positive aspects of the drug are its wide safety margin, rapid
and comfortable entry into anesthesia, good muscle relaxation
and pain relief, minimal suppressive effect on cardiac and
respiratory systems, and rapid and comfortable emergence
from anesthesia. T h e negative aspects of the drug are that
it increases saliva secretion and the prepared solution must be
consumed within 3 days (if stored in the refrigerator, the time
may be longer) (5). When tiletamine is used together with
zolazepam, convulsions that occur when the drug is
administered alone are prevented (21, 25).
The size, age, temperament and general condition of
the animal should be taken into account before using Zoletil.
Gender is also something to be taken into consideration.
Because male and female animals respond differently to
zoletil (21).
Phenothiazine and Opioid Mixtures Usually one of the phenothiazines is used in combination with opioids to provide simple sedation (30). The doses of both drugs are the doses used in premedication. The combination of methadone + propionylpromazine + atropine is widely used in Europe for sedation. Another combination used is papaverine (20 mg) + scopolamine (0.4 mg)+asepromazine (0.3 mg), used as a sedative in German
Shepherd dog breeds. Another recommended combination is a
mixture of acepromazine (0.07 mg/kg)+buprenorphine (9 μg/kg)
or pethidine (3.3 mg/kg) administered via the SI route.
Xylazine or medetomidine can also be used instead of
asepromazine. The combination of medetomidine (40
μg/kg)+butorphanol (0.05 mg/kg) in combination with the
administration of medetomidine (40 μg/kg)+butorphanol (0.05
mg/kg) provides a more profound effect than the sedation
achieved with medetomidine alone. Opioids such as fentanyl or
etorphine are also used to provide deep sedation (14).
As is well known, cats respond to opioids with a
strong stimulus. Therefore, they are not used in cats.
However, when opioids such as pethidine (1-2 mg/kg) are
given together with asepromazine at low doses, a sedative
effect may occur; but in this case, the dose of asepromazine
should be kept low (15).
Concomitant Medicines
The aim of the combined use of drugs for sedation and
immobilization in cats and dogs is to increase the effects of the
drugs, reduce the side effects and the dose administered (Table
5).
Medicines to be used in special cases
Animals that are restless after the operation are
sedated with sedatives such as asepromazine. The animal may
be sleep deprived due to pain or being in a busy area prior to
the operation, resulting in a deep or prolonged period of
sleep. This can mistakenly lead the physician to believe that
the animal does not need opioid painkillers or that an
overdose has occurred. The effects of opioids are enhanced
by other sedatives.
In some cases it is difficult to decide whether the
animal's restless state is due to pain or a systemic disorder. A
physical examination of the respiratory, circulatory and
excretory systems is necessary. A good physical examination
is necessary to prevent stress in the animal (17).
An animal that is excited, in pain or frightened will
have increased sympathetic stimulation and increased blood
flow to the heart, muscles and liver. In these animals,
sedatives or tranquilizers can reduce these effects.
In weak animals, slow and careful DI injection of sedatives
and anesthetics may be the preferred technique. This is because
these animals are sensitive to high doses of the drugs used. In
animals with heart failure (heart failure due to heart disease
and hypovolemia and usually old or sick animals), the time to
onset of action may be longer than in normal animals. This may
result in high doses of medication being administered.
Ketamine 2.0-10.0
DI, KI
It should not be used alone in
dogs.
Immobili
zing effect in cats is 5-30 minutes.
This is because the time for the drugs to reach the target organs
has increased. The physician is advised to identify these animals
and wait before increasing the dose. DA in animals with
reduced heart rhythm
Tiletamine
/
Zolazepam
(Zoletil)
2.0-8.0
KI, DI
It should be used within a
short time after preparation.
Immobilizing effect 20 minutes to
1 hour
In injections, the drug is absorbed slowly, which is due to lack of
perfusion in the skin. In this type of animal, DA is not absorbed
from injections
should be avoided.
It is known that the effects of sedative or tranquilizing substances are increased in a certain way in animals that are generally calm and kept in a quiet environment during drug administration. However, in painful and stressful interventions, the expected effect may decrease (17).
Preparations
The preparations of substances used as sedatives and immobilizers in cats and dogs available in Turkey are given in Table 6.
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