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Lectures in Veterinary Anesthesia

Muneer S. Al-Badrany

 Anticholinergics

 Tranquilizers /
 Narcotics
 Neuroleptanalgesics
 Dissociative agents
Preanesthetic drugs will be discussed according to the following five categories:

Lectures in Veterinary Anesthesia

Muneer S. Al-Badrany





All premedication drugs, except the anticholinergics, are considered central nervous system (CNS) depressants
Contraindications
It must be remembered that these drugs will cause a certain degree of respiratory and cardiovascular depression, especially if used in high doses. Thus caution must be exercised when dealing with animals in respiratory or cardiac failure
Animals in hypotensive shock should not receive tranquilizers or narcotics unless careful mon­itoring is combined with the use of intravenous fluids.
Excessive administration of atropine, especially via the intrave­nous route, can lead to atropine poisoning, which can sometimes be fatal.
because they cause a sustained paralysis of the ciliated epithelium in the trachea and bronchi Their use results, on occasion, in overly thick mucous production

Lectures in Veterinary Anesthesia

Muneer S. Al-Badrany

Anticholinergics (sympathomimetics)

Drugs in this category are given primarily to counteract certain actions of tranqulizers, narcotics, and general anesthetics that is, bradycardia, excessive salivation, and increased vagal tone caused by anesthetics, tracheal intubation, or surgical manipulations. Atropine sulfate is a commonly used anticholinergic drug
As an antidote or organophosphate intoxication
As an antispasmodic to control diarrhea and/or vomiting
Advantages
 Stabilization of heart rate by counteracting vagal tone, there by increasing heart
rate
 Prevention of excessive secretions from the salivary and tracheal glands, which results in drying of the mouth and upper respiratory tract


Lectures in Veterinary Anesthesia

Muneer S. Al-Badrany

 The production of excessively thick mucus from the trachea and bronchi

 Increased anatomic dead space caused by a dilation of bronchial
airways, which could be of importance in brachycephalic animals or those with chronic respiratory disease.
In animals with cardiac disease associated with arrhythmias and/or tachycardia
In animals with uncompensating respiratory disease or distress
In constipated animals because of the drug’s antiperistaltic action
In animals with severe renal dysfunction
Precautions
Disadvantages

Lectures in Veterinary Anesthesia

Muneer S. Al-Badrany

Specific examples of anticholinergic drugs:

Atropine sulfate.
Other anticholinergic drugs
Scopolamine hydrobromide (hyoscine). Nicknamed “scope,” it has a sedative action on some species.
Methylatropine nitrate
Aminopentamide
Glycopyrrolate.
Duration of action is almost twice that of atropine. It does not readily cross the blood-brain barrier and is therefore less of a depressant.
Dose of atropine 022 to 0.044 mg/kg). Usually, atropine is given either iv, sc.

Lectures in Veterinary Anesthesia

Muneer S. Al-Badrany





Principles of sedation, analgesia and premeditation
1- Sedation
Effective Sedation :
careful selection of the drugs
Procedures
Species of animals
In all cases Animals is left undisturbed adequate period

Lectures in Veterinary Anesthesia

Muneer S. Al-Badrany

1-Phenothiazine derivatives

Antipsychotics, calming, powerful antiemetic action, didn’t have analgesic effect, action blocking 1 adrenoceptors, antiadrenaline effect, hypotension (peripheral vasodilatation, decrease body temperature
Aceptromazine (Acetylpromazine) Calmivet
Chloropromazine
Propionylpromazine (Comblene)
Dose:
Horse, 0.05-0.1 mg/ kg B.w,
Dogs: 0.05-0.1 mg/kg B.W.
Cattle 0.5-1 mg /kg B. W.