Clinical pharmacology of analgesics Flashcards
Name classes of analgesics
Opiods
NSAIDS
Local aesthetics
Alpha2 agonist
Ketamine
What is the mechanism of opiods
activate opioid receptors to reduce neuronal excitability
Indications for the use of opiods
To relieve acute/moderate/severe pain
To provide sedation-Alone or in combination with other drugs
To reduce required dose of general anaesthetic
Contra indications for the use of opiods
Existing hypoventilation e.g. ruptured diaphragm
Elevated intracranial pressure (ICP) e.g. head trauma or brain tumours
What is the mechanisms of NSAIDS
inhibit production of prostaglandins & thromboxanes by cyclo-oxygenase enzymes (COX)
Indications for NSAIDS
Pain management - Acute and chronic
Management of inflammatory disorders
- Antipyretic agents
- Management of endotoxaemia
Management of pro-thrombotic states
- E.g. feline hypertrophic cardiomyopathy
Management of specific tumours
- E.g. transitional cell carcinoma of the urinary bladder
Contraindications of NSAIDS
Gastrointestinal tract disease, especially GI ulceration
Acute or chronic renal disease
Low effective circulating volume
Impaired hepatic function
Haemostatic disorders
Patients concurrently treated with steroids
Breeding, pregnant or lactating animals
Patients with unstable asthma
An NSAID which has reduced risk of gastrointestinal toxicity has increasing specificity of which COX
COX 2
What is the mechanism of Grapiprant
Antagonist of prostaglandin E2 at EP4 receptors
Production of “physiological” prostaglandins not inhibited that has fewer side effects
Mechanism of local anaesthetics
block sodium channels preventing the initiation & conduction of action potentials
Contraindications for local anaesthetics
Mostly relate to techniques rather than drugs
Should I give firocoxib or phenylbutazone to a patient with existing GI issues
Lower risk of GI ulcers with firocoxib
What drug should i give if i want an emergency quick onset analgesia
IV fentanyl
