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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) PAMIDRONATE
2) PREGABALIN
a) Classification
i) A calcium channel blocker felt to have similar affects and applications as does its "cousin", gabapentin b) General Information
i) An oral prescription medication capable of helping reduce neuropathic and other chronic pain states (1) Pregabalin suppresses central sensitization[1] ii) Originally developed as an anticonvulsant iii) Unlike gabapentin, pregabalin possesses liner pharmacokinetics; increasing doses deliver increasing drug plasma levels[2] iv) In addition, pregabalin is much more rapidly absorbed from the PO route v) Oddly, in the US, each of the 8 pregabalin sizes is priced the same c) Advantages/Recommended use
i) Chronic pain management ii) Preoperative analgesic adjunct ii) Preoperative anxiolyic[3] iii) Generally free from adverse effects or drug interaction d) Cautionary Information
i) Chronic use may cause a transient drowsiness usually lasting no more than a few days ii) Excreted unchanged in the urine (1) Reduce dose or discontinue in patients with renal dysfunction iii) Withdraw this drug gradually to avoid rebound pain e) Dosage Information
[4, 5, 6]
i) Dogs & Cats (1) 1.0 to 5 mg/kg (0.5 to 2.5 mg/lb) BID to TID PO ii) May be able to gradually reduce dose if doing well after extended therapy iii) Available in 25, 50 75, 100, 150, 200, 225, and 300 mg sizes f) Cost
1 Central sensitization and Ca(V)α₂δ ligands in chronic pain syndromes: pathologic processes and pharmacologic effect. Tuchman M, Barrett JA, Donevan S, Hedberg TG, Taylor CP. J Pain. 2010 Dec;11(12):1241-9 2 A comparison of the pharmacokinetics and pharmacodynamics of pregabalin and gabapentin. Bockbrader HN, Wesche D, Miller R, Chapel S, Janiczek N, Burger P. Clin Pharmacokinet. 2010 Oct 1;49(10):661-9 3 Pregabalin--profile of efficacy and tolerability in neuropathic pain. Stump P. Drugs Today (Barc). 2009 Oct;45 Suppl C:19-27 4 Pharmacokinetics of single-dose oral pregabalin administration in normal dogs. Salazar V, Dewey CW, Schwark W, Badgley BL, Gleed RD, Horne W, Ludders JW. Vet Anaesth Analg. 2009 Nov;36(6):574-80. 5 Pregabalin as an adjunct to phenobarbital, potassium bromide, or a combination of phenobarbital and potassium bromide for treatment of dogs with suspected idiopathic epilepsy. Dewey CW, Cerda-Gonzalez S, Levine JM, Badgley BL, Ducoté JM, Silver GM, Cooper JJ, Packer RA, Lavely JA. J Am Vet Med Assoc. 2009 Dec 15;235(12):1442-9. 6 The seizuring cat. Diagnostic work-up and therapy. Smith Bailey K, Dewey CW. J Feline Med Surg. 2009 May;11(5):385-94. Review.
3) PROPOFOL
a) Classification
i) Propofol is an alkylphenol derivative suspended in a hyperlipid emulsion b) General Information
i) A very fast acting injectable without cumulative effect c) Advantages/Recommended use
i) Generally for: (1) Cases when rapid recovery is desired (2) Diabetes Mellitus (a) Propofol is capable of providing a smooth and rapid return to a comfortable state if premedications are appropriately utilized (b) Appetite appears increased in many patients for a short period of time after recovery from propofol (3) Outpatient procedures (4) Sighthounds (5) C sections (6) Liver disease (7) Giant breed dogs when early ambulation is desired ii) Can be given as intermittent bolus or constant rate infusion (CRI) for maintenance of anesthesia iii) Can be combined with 2% Thiopental in a 50/50 ratio (1) Improves stability/shelf life (a) This combined product should be handled carefully and refrigerated for storage (b) It should be used within 24 to 48 hours of the propofol’s opening (2) Dose at same volume you would calculate if using propofol alone d) Cautionary Information
i) Predictable respiratory depression and hypotension if given rapidly (1) Should not be a major concern if given slowly ii) Hyperlipid emulsion easily promotes bacterial growth (1) Once opened, nonpreservative product should be used within 6 - 12 hours iii) When use in patients with hepatic dysfunction the clearance times may be doubled (1) There is some pulmonary clearance iv) Use caution when dealing with ill cats 1 (1) Phenol can induce Heinz body anemia (2) This is most concerning with ongoing administration: i.e., intermittent bolus or CRI based propofol maintenance anesthesia e) Dosage information
i) Routine induction
(1) Dogs (a) 4 to 6 mg/kg (2 - 3 mg/lb) if not depressed or sedate (i) Effective premeds or pre-existing CNS depression or debilitation can reduce the dose required for intubation to 1 to 4 mg/kg (0.5 to 2 mg/lb) (2) Cats (a) 6 to 8 mg/kg (3 - 4 mg/lb) if not depressed or sedate (ii) Effective premeds or pre-existing CNS depression or debilitation can reduce the dose required for intubation to 1 to 4 mg/kg (0.5 to 2 mg/lb) or less (3) 25 % slowly IV every 60 seconds to effect (a) Rapid administration causes: (i) Apnea of short duration (ii) Hypotension (iii) Reduction in myocardial contractility (4) If, at any point, the canine patient is nearly, but not quite, able to be intubated, the addition of 2 mg/kg (1 mg/lb) lidocaine IV, may deepen the anesthetic effect and facilitate successful intubation (a) This strategy is useful when minimizing the induction agent for more critical patients (b) Cats are more sensitive to the toxic effects of lidocaine (CNS stimulation, seizures). Lidocaine is not recommended for use in cats at this time. (5) Diazepam 0.2 to 0.4 mg/kg (0.1 to 0.2 mg/lb) IV can decrease propofol need by 50% (6) Routes of administration (a) IV (b) Intraosseous ii) Routine maintenance
(1) Dogs
(a) Boluses of ¼ to 1/3 of the original induction dose as needed (b) CRI at 0.05 to 0.4 mg/kg/minute (0.025 to 0.2 mg/lb/minute) (i) If too light, give 0.5 to 1.0 mg/kg (0.25 to 0.5 mg/lb) IV then increase CRI rate by 25% (ii) If too deep, stop propofol until suitable anesthetic level is reached, then reinitiate CRI at 25% lower rate (2) Cats1,2,3,4 (a) Boluses of ¼ to 1/3 of the original induction dose as needed (b) CRI at 0.05 to 0.2 mg/kg/minute (0.025 to 0.1 mg/lb/minute) (i) If too light, give 0.5 mg/kg (0.25 mg/lb) IV then increase CRI rate by 25% (ii) If too deep, stop propofol until suitable anesthetic level is reached, then reinitiate CRI at 25% lower rate (iii) Feline patients do not clear phenols well, repetitive day to day use not recommended (c) Subsequent boluses or ongoing CRI doses should be adjusted downward over time (d) Recovery will be more prolonged than with dogs f) Cost
i) Moderate
1 The effects of consecutive day propofol anesthesia on feline red blood cells. Andress JL, Day TK, Day D. Vet Surg. 1995 May-Jun;24(3):277-82. 2 Repetitive propofol administration in dogs and cats. Matthews NS, Brown RM, Barling KS, Lovering SL, Herrig BW. J Am Anim Hosp Assoc. 2004 Jul - Aug;40(4):255-60. 3 The effect of the duration of propofol administration on recovery from anesthesia in cats. Pascoe PJ, Ilkiw JE, Frischmeyer KJ. Vet Anaesth Analg. 2006 Jan;33(1):2-7. 4 Clinical assessment of repeated propofol-associated anesthesia in cats. Bley CR, Roos M, Price J, Ruess-Melzer K, Buchholz J, Poirier V, Kaser-Hotz B. J Am Vet Med Assoc. 2007 Nov 1;231(9):1347-53.
4) PROPOXYPHENE (DARVON)
a) An opioid analgesic who's use is being discouraged in the US due to cardiac toxicity concerns |
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