Practical 6: Sedatives

Observation of the effect of chlorpromazine and xylazine.

What is a sedative?

A sedative is a substance that induces sedation by reducing irritability or excitement.

• injected either into a muscle or directly into vein.

• used in combo as pe-anaesthetics before general anesthesia to relax and sedate the animal. Some also giving analgesia.

What is neuroleptanalgesia?

a state of sedation and pain control induced for a medical procedure by a combination of opioids analgesics and neuroleptics (sedatives/benzodiazepines).

what is neuroleptanesthesia?

Refers to the state after the inclusion of anesthetics, where the animal is not only sedated but also fully anesthetized for more invasive procedures.

Name five major classes of sedative drugs in veterinary medicine.

1. Phenothiazines - acepromazine

2. a2-adrenergic agonists - xylazine, detomidin, medetomidin, dexmedetomidin, romifidin

3. benzodiazepines - diazepam, zolazepam, midazolam

4. butyrophenones - azaperone

5. Rauwolfa alkaloids

To Phenothiazines belong?

Acepromazine

To a2-adrenergic agonists belong?

1. xylazine

2. detomidin

3. medetomidin

4. dexmedetomidin

5. romifin

To butyrophenones belong?

azaperone

Chlorpromazine is used as?

tranquilizer and antiemetic in small animals, also as a pre-operative medication sometimes. It gives a calming effect, but lacks the analgesic effect, thus a local anaesthetic must be used at surgcial operations.

What effects does Acepromazine have on animals?

Acepromazine decreases anxiety, causes CNS depression, and results in a drop in blood pressure and heart rate.

How is Acepromazine often used with other medications?

Acepromazine is commonly used with atropine as a pre-operative medication and can be combined with opiates and sedatives in dogs.

What are the advantages of using Xylazine?

Xylazine is a potent alpha2-adrenergic agonist that acts as a sedative/analgesic with muscle relaxant properties, causing skeletal muscle relaxation.

What is the sensitivity of ruminants to Xylazine?

Ruminants are extremely sensitive to xylazine and typically require about 1/10th of the dosage used for horses to achieve the same effect.

What types of procedures can Detomidine be used for in animals?

Detomidine have analgesic properties, used for handling animals for examinations, minor surgical procedures, and other manipulations.

What is Medetomidine used for?

Medetomidine is used to induce sedation and analgesia in animals before clinical examinations and small surgery.

What is the use of Dexmedetomidine?

Used as a sedative and analgesic in dogs and cats for clinical examinations, clinical procedures, minor surgical procedures and minor dental procedures.

• effective as pre-anaesthetic in dog, cat before general anesthesia.

What type of sedation can Benzodiazepines provide?

Benzodiazepines are “minor tranquilizers”, used to induce anxiolysis, sleep, sedation, and can be used as anticonvulsants in veterinary medicine.

What is Azaperone primarily used for?

Azaperone is most commonly used for tranquillisation and sedation in swine, particularly to manage aggression when mixing or regrouping pigs.

• generally causing tranquilisation and sedation, anti-emetic activity and reduces motor activity.

What are antagonists of neuroleptics and sedatives used for?

They are used in overdose or to cancel the effects of neuroleptics and sedatives.

• in particular the atipamezole (a2-adrenergic antagonist).

What is an example of an alpha-2-adrenergic antagonist used to reverse sedatives?

Atipamezole

• for the reversal of the clinical effects of the sedative and analgesic agents, dexmedetomidine (dexdomitor) and medetomidine (domitor) in dogs and cats.

MPPs:

Rompun inj. sol. AS and I:

AS: xylazine

I: Sedative for cattle, horses, dogs and cats

(opioid)

MPPs:

Sedalin oral gel. AS and I:

AS: Acepromazine

I: sedative for dogs and cats

(opioid)

MPPs:

Stresnil sol. for inj. AS and I:

AS: Azaperone

I: sedative-neuroleptic for swine

(opioid)

MPPs:

Domitor inj. AS and I:

AS: Dexmedetomidine (medetomidine hydrochloride)

I: Dogs and cats - restraint, sedation and analgesia

• in clinical examinations and procedures, minor surgery and pre-anaesthesia.

(Opioid)

MPPs:

Antisedan inj. AS and I:

AS: Atipamezole

I: Anti-sedative agent, dogs and cats

(opioid)

MPPs:

Domosedan inj. AS and I:

AS: Detomidine

I: Sedative, analgesic (use in all animals, not in late stage pregnancy horses)

(opioid)

MPPs:

Torbugesic inj. AS and I:

AS: Butorphanol

I: Analgesic, sedative, horses, dogs, cats

(opioid)

How do analgesics suppress the sense of pain?

Analgesics suppress the sense of pain by affecting corresponding parts of the central nervous system (CNS) including the hypothalamus, thalamus, and brain cortex.

What is morphine and its significance in veterinary medicine?

Morphine is one of the most potent analgesics in human medicine, and while effective, it can have an irritating effect on some animal species depending on their CNS development.

Analgesics are referred to drugs belonging to morphine group. What drugs are included in this group?

• morphine

• codeine

• heroin

• pethidine

• methadone

• thiamorphine

• and synthetic compounds like fentanyl.

what is the function of antipyretic-analgesic-anti-inflammatory drugs?

Less analgesic action - acetyl-salicylate, salicylate, ibuprophen ex.

What are opium and morphine derived from?

Morphine is an opiate alkaloid obtained from opium, which is the dried milky exudate from the Oriental poppy plant (Papaver somniferum).

effects: analgesia, resp. depression, sedation, emesis, physical dependence + intestinal effects.

• secondary: CNS (euphoria, sedation, confusion), cardiovascular (bradycardia), urinary (inducing urinary retention).

opium alkaloids may be? (2 groups)

1. Phenantrene derivatives - morphine, codeine, thebaine

2. isoquinoline derivatives - papaverine, narcotine, narceine

What is hydromorphone and how does it compare to morphine?

Hydromorphone is a morphine derivative with a similar duration of effect. It produces less of an emetic effect than morphine, but emesis and nausea can still occur relatively frequently.

What is oxymorphone and its potency compared to morphine?

Oxymorphone is a morphine derivative that is 10 times more potent than morphine. It produces less emesis, nausea, and sedation compared to both morphine and hydromorphone when administered to dogs and cats.

What is the role of codeine in veterinary medicine?

Codeine is a naturally occurring alkaloid similar in structure to morphine and is used as an antitussive drug. Parenteral administration provides weak analgesic effects and is effective only for mild pain, making it rarely indicated for use in veterinary medicine.

How is fentanyl used in veterinary settings?

Fentanyl is a very potent opiate agonist available in intravenous and transdermal preparation, primarily used in dogs and cats for adjunctive control of postoperative pain through transdermal patches.

What are sufentanil, alfentanil, and remifentanil known for?

Sufentanil, alfentanil, and remifentanil are fentanyl derivatives that exhibit similar pharmacodynamic effects as fentanyl. Sufentanil is 5 to 7 times more potent than fentanyl, while remifentanil has a unique non-hepatic metabolism resulting in a short terminal half-life and rapid clearance in dogs.

What is buprenorphine and its potency?

Buprenorphine is a thebaine derivative and a synthetic partial opiate agonist considered to be 30 times as potent as morphine, producing dose-related analgesia.

What is butorphanol and its effectiveness in pain relief?

Butorphanol is a synthetic opiate partial agonist that is structurally related to morphine and is considered to be 4-7 times as potent as morphine for analgesia, also possessing significant antitussive activity.

What is pentazocine and its pharmacological effects?

Pentazocine has similar pharmacological effects as butorphanol and nalbuphine, effective for mild to moderate pain with a duration of effect of 1-3 hours. It may cause less sedation compared to other opioids but can still result in excitement and tremors at high doses.

What is naloxone and its purpose in veterinary medicine?

Naloxone is an opioid antagonist that binds to μ-, κ-, and δ-receptors without activating them, used postoperatively to reverse respiratory depression caused by μ receptor opioids and in neonates following cesarean delivery.

What is naltrexone and its applications?

Naltrexone is a long-lasting opioid receptor antagonist used to reverse opioid-induced respiratory depression and immobilization effects of potent opioids, administered IV or IM, especially in wildlife and large animals, and can be given orally to treat behavioral problems in dogs.