Short topics Flashcards
Tranqulizers
Neuroleptic
Decrease motor activity and response to stimuli and fear
Not analgesic- potentiates analgesic effect
Increased dose-increased length of sedation
Indications
Anti-dopamin: sedation, antimetic
Antihistamine: Allergy
Combinations: preanesthesia, neuroleptanalgesia
Side effects Hypotension-collapse Tissue irritant Epileptic seizures Lack of thermoregulation
Phenothiazine traqulizers:ACP, chlorpromazine, propionylpromazine, promethazine-aggressive animals
Butyrphenone tranqulizers:Azaperone(pigs), droperidol, fluanisone
Sedatohypnotics
alfa2 agonists, benzodiazepines, propan-diol derivates and barbiturates
Sedative, anxiolytic, muscle relaxant, anticonvulsive
Increased dose: Deeper sedation analgesia and muscle relaxant
Physiological effect:
Activates postsynpatic receptors-vasoconstriction, transient hypertension, baroreceptor activation, bradycardia
Activates presynaptic a2 receptors- hypotension, analgesia and sedation, decreased motor activity, intraoccular pressure and salvation.
IM/IV: moderate analgesia
Combined with ketamine or butorphanol for general anasthesia
Opioids
Analgesia, sedation, euphoria, cough relief and antidiarrhoeal
mu-opioid receptor: specific strong analgesic effects, slight sedation and antitussive
kappa-opioid receptor: slight analgesic and sedation effect
delta-opioid receptor: analgesia, eye! Dextromethorphan is antitussive also
Metabolised in liver, fentanyl very lipoohilic
Side effects: resp depression, emesis, bradycardia, obstipation, histamin release, hyperthermia, excitation, dysphoria
Inhalation anaesthetics
Halogenated volatile liquids(except nitrous oxide)
Decreased cerebral vascular resistance with increased perfusion to brain
Activation of ligand-gated ion channels- increased cl conductance, hyperpolarise and inhibit neuronal membrane activity
Inhibit ligand gated sodium channels
MAC(minimum alveolar conc)- 50% are immobile, decrease with age, prenancy, hypothermia, hypotension
Injectable anaesthetics
Ideal properties:water and lipid soluble, sufficiently potent, muscle relaxant, non-irritant, rapid and safe induction and recovery, limited effect on vital functions, high TI, no hepato/nephrotoxicity, rapid metabolism, antagonist available, no chemical or pharmalogical incompatability
Barbiturates-GABA receptors- unconsciousness, muscle relaxant(propofol, pentobarbital, thiopental)
Can be combined with opiates for analgesia.
Accumulation in adipose tissue- no redistribution
Quick and complete distrubution- crosses bbb and placenta, short acting
Imidazoles: etomidate-safest
Dissociative anaesthetics:ketamine
Anticonvulsants
Seizure:caused by high frquency discharge of a group of neurons starting locally and spreading to the rest of the brain, may be partial or generalised. Reticular formation involved- unconsciosness
Monotherapy is generally preferred but combinations can be used: phenobarbital, phenytoin, carbamazepine
Status epilepticus: diazepam
Prvention:phenobarbital, imepitoin, gabapentin, levetiracetam, potassiium bromide.
GABA receptor mediated inhibitory effect
Antidepressants and behaviour modifying drugs
Classes to treat anxiety, mania, phobias and depression:Sedatives, antiepileptic, pheromones, opioids, antihistamines, antidepressants
The antidepressants: TCA(amitriptyline and clomipramine) SRI(prozac) MaOI(Selegiline) Lithium
Benzodiazepines(alprazolam, lovazepam, diazepam)
Peripheral muscle relaxants and spasmolytics
Complete neuromuscular blocking agents
Selectively antagonise nicotinix receptors by preventing endogenous ACh binding- no depolarisation, sucess when 90% of receptors are occupied.
Tubocurare, atracurium, rocuronium, vecuromium
Antagonist: Neostigmine
Depolarising neuromuscular blocking agents
Spasmolytics:depress the CNS-paralysis of voluntary movement
Smooth muscle relaxants(papaverine): parasympatholytics and sympathomimetics
Local anaesthetics
Work by blocking nervefibre conduction(sodium channels) without loc(level of consciousness) or cns depression. Causing loss of sensation and sometimes paralysis.
Esters:procain, oxybuprocain, tetracaine
Amids:Lidocaine, prilocaine, bupivacaine, ropivacaine, articaine
Block conduction in following order: axons, non-myelinated axons, small myelinated, large myelinated
Order of dissaperance: pain-warmth-touch-deep pressure-motor
Indications
Topical:cornea, mucosa, skin
Local infiltration: SC
Perineural injection: peripheral nerve block
Intraarticular: lameness, operation
IV: distally, prilocaine, operations of digits in cattle
Epidural/spinal block
Digitalis glycosides and phosphodiesterase inhibitors
Positive inotropic drugs, increase myocardial contractility, and are used in the treatment of chronic heart failure.
CHF symptoms: murmur, coughing, cardiomegally, purple mucosa, oedema.
Heart performance is affected by contractility, preload, afterload, frequency
Digitalis glycosides increase contractility
PDE inhibitors increase contractility and vasodilation
ACE inhibitors decrease preload and afterload
Diuretics decrease preload
Nitroglycerine is a vasodilator
Adrenaline increase heart rate
Digitalis glycosides(digoxin)
Inhibit Na/K pump-activates Na/Ca pump
PO, accumulates in muscle
PDE inhibitors(pimobendan)
PDE decrease cAMP, so PDE inhibitors increase cAMP accumulation- leads to increased Ca in cells
PO 1 hour before food, extensive protein binding
