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Veterinary Anesthesia & Analgesia Support Group |
| Practical Information for the Compassionate Veterinary Practitioner |
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| Alphabetical Drug Summaries | ||
| Dr. Bob Stein | ||
1) ACEPROMAZINE
a) Classification
i) phenothiazine tranquilizer
b) General Information
i) Very inexpensive, effective tranquilizer for healthy animals ii) Clinically more effective in dogs than cats iii) Duration of effect is 6 to 8 hours (1) Some pets appear sedate for more than 12 hours iv) Acepromazine can be used alone, as a premedicant. However, it is more effective to use Acepromazine in combination with an opioid narcotic agent (1) The addition of an opioid reduces the acepromazine dose, and therefore also reduce the likelihood of hypotension or sustained, excessive sedation that can occur c) Advantages/Recommended use
i) Decreases patient stress and anxiety ii) Helps protect against catecholamine induced arrhythmias iii) Decreases amount of induction and maintenance anesthetics iv) The injectable product can be given orally @ 1.0 to 2.0 mg/kg (0.5 to 1.0 mg/lb) for tough animals (1) For extremely difficult patients, acepromazine at above dose can be combined with 5 to 20 mg/kg (2.5 to 10 mg/lb) telazol solution and given orally on an empty to produce effective chemical restraint (a) At the upper dose range expect laterally recumbent animals within 30 to 45 minutes d) Cautionary Information
i) Use of acepromazine as a sole agent is not recommended ii) Can have profound and prolonged effects when used on older or debilitated patients iii) There are still references to acepromazine lowering the seizure threshold for epileptic patients (increased seizure risk) (1) Many anesthetists feel this is not a significant risk at the doses currently recommended iv) May decrease seizure potential in myelogram cases (decreased seizure risk) v) May decrease PCV (up to 30%) (1) Avoid in anemic patients vi) Avoid in splenic disease patients (1) Induces splenic enlargement/engorgement vii) Not well tolerated by patients with liver disease viii) Many feel that Boxers require lower doses than other dogs of similar size and disposition e) Dosage Information
i) Dogs (1) Dose ranges from 0.005 mg/kg to 0.1 mg/kg (0.0025 mg/lb to 0.05 mg/lb) IV, IM, SC (a) Combine with an opioid (b) Most commonly used at 0.010 to 0.040 mg/kg (0.005 to 0.02 mg/lb) when combined with an opioid (2) Dosing is more appropriately considered based upon body surface area (a) The heavier the patient, the lower the dose per unit of body weight (3) Maximum total dose is 2 mg regardless of weight
(a) Some go as high as 3 mg total dose
ii) Cats (1) Dose ranges from 0.020 to 0.10 mg/kg (0.01 mg/lb to 0.05 mg/lb) IV, IM, SC (a) Combine with an opioid (2) Smaller, younger patients usually require 0.06 to 0.10 mg/kg (0.03 to 0.05 mg/lb) (3) When combined with a mu agonist opioid give 0.06 to 0.10 mg/kg
(0.03 to 0.05 mg/lb)
(a) Inadequate acepromazine dose associated with undesirable excitement
f) Cost
i) Very low
2) ALFAXALONE
3) AMANTADINE
a) Classification
i) Developed initially as a human antiviral drug,
also used to treat Parkinson’s disease
b) General Information
i) An oral prescription medication capable of NMDA antagonism useful in managing the central sensitization component of chronic pain management ii) The dopamine selectivity of amantadine’s monoamine reuptake inhibition appears to allow for coadministration with other less selective monoamine reuptake inhibitors (tramadol, TCAs, SSRIs, MAO inhibitors) c) Advantages/Recommended use
i) Chronic pain management d) Cautionary Information
i) Amantadine is excreted, primarily unchanged, in the urine (1) Consider reduced doses, if used at all, for patients with impaired renal function ii) May potentiate the effects of sedative medications iii) Use with caution in nursing animals iv) Side effects are rare, but can include agitation or diarrhea e) Dosage Information
i) Dogs & Cats (1) 3 to 5 mg/kg (1.25 to 2.5 mg/lb) SID PO (2) Can be given continually or as a 7 to 14 day pulse therapy ii) Available in 100 mg gelcaps and 10 mg/ml liquid f) Cost
i) Capsules and Liquid - Moderately low ii) Tablets - Moderately high
4) AMIDATE
a) Abbott’s brand name for Etomidate
5) AMITRIPTYLINE (TCAs)
a) Classification
i) Tricyclic antidepressant prescription drug
b) General Information
i) Monoaminergic reuptake inhibition (serotonin, norepinephrine) enhances central pain inhibition ii) Possible opioid receptor activity as well or, at least, enhanced effectiveness of concurrently administered opioids c) Advantages/Recommended use
i) Chronic pain management d) Cautionary Information
i) Do not combine with other TCAs, SSRIs, MAO inihibitors, or tramadol due to the risk of serotonin syndrome. ii) May potentiate the effects of sedative medications iii) Has anticholinergic effects e) Dosage Information
i) Dogs (1) 1 to 2 mg/kg (0.5 to 1.0 mg/lb) SID to BID PO ii) Cats (1) 2.5 to 12.5 mg/cat SID iii) Available in 10, 25, 50, 75, 100, and 150 mg tablets f) Cost
i) Moderate (1) May need to be compounded to allow for proper dosing
6) ATIPAMAZOLE
a) Classification
i) Alpha-2 antagonist b) General Information
i) Reversal agent for medetomidine or xylazine c) Advantages/Recommended use
i) Completely, permanently reverses medetomidine effects (1) Can be used at partial dose for partial effect d) Cautionary Information
i) Reversing all of medetomidine’s sedative effects will also lead to loss of analgesic effect e) Dosage Information
i) Dogs (1) Normally match route and volume of medetomidine given (a) Reduce dose according if sedative effects of medetomidine have warn off (b) Reduce dose accordingly if you prefer to retain some analgesic and sedative effect ii) Cats
(1) Normally give 1/2 the volume of the medetomidine given as a
starting point
(a) Reduce dose according if sedative effects of medetomidine have warn off (b) Reduce dose accordingly if you prefer to retain some analgesic and sedative effect f) Cost
i) High
6) ATROPINE
a) Classification
i) Anticholinergic b) General Information
i) Decreases salivary secretions (1) Can make them thicker, more ropey (a) Only reduces serous portion of salivary secretions leaving the thicker mucoid portion ii) Increases heart rate c) Advantages/Recommended use
i) Prior to procedure that stimulate strong vagal effect (1) Bronchoscopy (a) May need to postpone until after respiratory diagnostics have been completed ii) Prior to dental procedures to decrease salivary secretions (1) Most would argue against routine use here iii) Prior to brachycephalic anesthesia (1) Brachycephalics tend to have higher vagal tone making routine anticholinergic use a consideration (2) To decrease salivary secretions (a) Most would argue against routine use here iv) C-sections (1) Atropine does cross placenta making it preferred for use in this situation should the bitch become clinically bradycardic v) Cardiac emergencies involving bradycardia or cardiac arrest (1) A more rapid, forceful effect (2) Glycopyrrolate is a definite second choice in emergency cases (a) Slower onset (3) Hypothermia results in decreased depolarization of cardiac pacemaker cells, causing bradycardia. Since this bradycardia is not vagally mediated, it can be refractory to atropine. d) Cautionary Information
i) Partial dosing can lead to a centrally mediated bradycardic effect
ii) Use with caution in tachycardic patients (1) Tachyarrhythmias can be an undesirable effect (2) Increased heart rate increases myocardial oxygen demand iii) Pupilary dilation may be undesirable for certain ophthalmic procedure iv) Duration of effect is much shorter than glycopyrrolate (1) Only about 45 minutes v) Be especially cautious when used with patients on amitriptyline as that behavioral medication possesses anticholinergic properties e) Dosage Information
i) Dogs & Cats (1) 0.02 to 0.04 mg/kg (0.01 to 0.02 mg/lb) IV, IM, SC (a) This works out to 1 cc per 10 to 20 kg (20 to 40 lb) f) Cost
i) Very low |
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