Sedatives!

. Describe the concept of sedation, tranquilisation and anxiolysis; discuss how these overlap in veterinary pharmacology. 2. List four “classes” of sedatives commonly used in veterinary medicine: a2-agonists, phenothiazines, benzodiazepines, and butyrophenones. 3. Discuss the mechanisms of action of each of the above. 4. Discuss the routes of administration of each of these four classes of sedatives. 5. Discuss the main effects of these agents including side effects.

define sedative

low dose = calm, drowsy

high dose = sleep, NOT anaesthetised

define tranquiliser

low dose = calm, altert, responsive

high dose = catalepsy, altered state of consiousness

define anxiolytic

calm, with no altered responses to stimuli, no fight / flight.

What are the four main classes of sedatives?

alpha 2 agonists

phenothiazines

butyrophenones

benzodiazepines

name the four main classes of sedatives and give an example for each

alpha 2 agonists - medetomidine

phenothiazines - acepromazine

butyrophenones - fluanisone

benzodiazepines - midazolam

What is the MOA of a2 agonists

bind to a2 receptors in neurones, block noradreniline.

in PNS - post synaptic, symapthomimetic (vasocons)

in CNS - pre synaptic, sympatholytic (sedation)

medetomidine

What beneficial effects do a2agonists have

sedation, analgesia, muscle relaxation

medetomidine

what adverse effects do a2 agonists have?

Cv - vasoconstriction

diruesis

hyperglycaemia

muscle relaxation

sweating

medetomidine

What drug is used to antagonise a2 agonists

atipamezole

what is the MOA of phenothiazides

antagonises a1-adrenoreceptors → vasodilation

antagonises dopamine 2 receptors → sedation, muscle relaxation

acepromazine

what are the beneficial effects of phenothiazines

sedation, muscle relaxation, ani-emetic, anti-histamine, long lasting

acepromazine

what are the adverse effects of phenothiazines

redcued contractility - hypotension

syncope in brachycephalics

long-lastin g

acepromazine

what is the MOA of butyphenones?

dopamine-2 receptor antagonist → sedation, muscle relaxation

histamine receptor anatagonist → anti-emetic, reduces hypersensitivites

• Azaperone (pig)

• Fluanisone (rabbits & guinea pigs)

what are the beneficial effects of butyrophenones

sedation

muscle relaxation

anti emetic, anti histamine

long lasting

• Azaperone (pig)

• Fluanisone (rabbits & guinea pigs)

what are the adverse effects of butyrophenones

vasodilation, long lasting.

• Azaperone (pig)

• Fluanisone (rabbits & guinea pigs)

What is the MOA of benzodiazepines?

binds to GABA receptors

eg - diazepam, midazolam

What are the beneficial effects of benzodiazepines?

sedation

muscle relaxation

minimal CV / resp effects!

eg - diazepam, midazolam

what are the adverse effects of benzodiazepines

can cuse exitement, no analgesia

eg - diazepam, midazolam

What drug can antagonise benzodiazepines

flumazenil