ACE Inhibitors: Mechanism
Vasodilation
- Increase bradykinin
Lower blood pressure
- Prevent vasoconstriction
- Reduce sodium retention
- Reduce water retention
Increased cardiac function
- Reduce preload and afterload
- Decrease vascular resistance
- Increase cardiac output
ACE Inhibitors: Examples
Benazepril
Enalapril
Ramipril
ACE Inhibitors: Use
CHF (dogs, cats, ferrets)
Hypertension (dogs, 1st choice)
ACE Inhibitors: Contraindications and Side Effects
Can cause:
Hypotension
GI disturbances
Care: Hypovolaemia Hyponatraemia Acute Kidney Injury Azotaemia
Alpha-2 Agonists: Mechanism
Sympathomimetic
- Act on alpha-2 adrenoreceptors and mimic ligand binding
Leading to:
- Vasoconstriction, hypertension
- Reflex bradycardia
- Analgesia
- Muscle relaxation
- Sedation / anxiolysis
- Diuresis
- Uterine contraction
Alpha-2 Agonists: Examples
Xylazine
Detomidine
Medetomidine
Romifidine
Alpha-2 Agonists: Contraindications + Side Effects
Hyperglycaemia Sedation Mild respiratory depression Gut hypomotility Vomiting Diuresis Hypertension
Caution in: Cardiovascular disease Pregnancy Diabetes V&D
Alpha-2 Agonists: Uses
Sedation
Anaesthetic protocol
Inducing emesis in cats
Benzodiazepines: Mechanism
GABAergic
- Enhance effects of GABA at GABA/Cl- channel complexes
Benzodiazepines: Uses
Anxiety / Anxiolysis Skeletal muscular spasms Anti-convulsant Analgesia (colic) Pre-medication in anaesthesia
Benzodiazepines: Examples
Diazepam
Midazolam
Benzodiazepines: Contraindications + Side Effects
Mild respiratory suppression
Mild cardiovascular suppression
Increase excitement in healthy animals
Caution with:
CNS depression patients
Hepatic dysfunction / encephalopathy
Respiratory depression
Phenothiazines: Examples
Acepromazine
Phenothiazines: Mechanism + Use
CNS Depressant
Peripheral vasodilation
Uses: Sedation Pre-medication for anaesthesia Antiemetic Feline thromboembolism management Increasing laminar perfusion Urethral spasms
Phenothiazines: Contraindications + Side Effects
Hypotension
Cardiovascular disease
Hepatic disease
Anaemia
Beta-blockers: Examples
Timolol Betaxolol Atenolol Propanolol Esmolol
Beta-blockers: Mechanisms
Adrenergic blocking drugs
- Block beta-1 and -2 receptors
- Decrease aqueous production in eye
Beta-blockers: Uses
Anti-arrhythmic
Glaucoma
Anxiety
Hypertension
Beta-blockers: Contraindications + Side Effects
Bradycardia
Bronchoconstriction
Caution in:
Cardiovascular disease
Asthma
Low body weight
Parasympathomimetics: Mechanisms
Cholinergic/mimetic
- Simulate acetylcholine effects
- Act as cholinergic receptor agonists
OR Acetylcholinesterase inhibition
Leading to:
- Smooth muscle contraction
- Vasodilation
- Reduced heart rate
- Increased bodily secretions
Parasympathomimetics: Examples
Bethanechol
Pilocarpine
Neostigmine
Edrophonium
Parasympathomimetics: Uses
Bladder atony
Myasthenia gravis diagnosis
Acute myasthenic crises
Atrial tachycardia
Parasympathomimetics: Contraindications + Side Effects
Bradycardia
Hypotension
Vomiting
Diarrhoea
Caution with: Renal impairment Bronchial disease (esp. feline asthma) Peritonitis GI / urinary obstructions Uveitis
Alpha-adrenergic antagonists: Examples
Prazosin
Atipamezole
Phenoxybenzamine
