Veterinary Anesthesia & Analgesia Support Group
Practical Information for the Compassionate Veterinary Practitioner
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    M Drugs
    Alphabetical Drug Summaries
     
    Dr. Bob Stein
   
   

1)   MEDETOMIDINE

a)      Classification

i)        Alpha-2 agonist

b)      General Information

i)        Potent sedative/analgesic

ii)       Moderately long duration of effect (4 - 6 hours)

c)      Advantages/Recommended use

i)        Best reserved for young healthy patients needing a reversible agent

ii)       Significant reduction in induction agent and lower MAC of inhalants

(1)   Thiopental need may drop to 0.5 mg/lb or less

iii)     10 times more selective for alpha-2 vs. alpha-1 than xylazine

iv)     Can be used with ketamine and butorphanol as an IM anesthetic protocol for short procedures in cats

d)      Cautionary Information

i)        DO NOT USE AS SOLE AGENT AT BOX LABEL DOSES

      (1) Label doses are as high as 0.080 mg/kg at smaller patient size

ii)   Do not use in debilitated or cardiovascularly unstable patients

iii)     Extremely stressed patients may not respond as well

(1)   Isolate in quiet, dark room if possible to facilitate effect

iv)     May cause dramatic bradycardia

(1)   This can rarely be a an unresponsive, fatal bradycardia

(2)   Anticholinergic use is not routinely recommended

(a)    Anticholinergic need is best determined by monitoring patient blood pressures

v)      Alpha-2 agonists depress insulin production

(1)   Use with caution or avoid in non-insulin dependent diabetics

e)      Dosage Information

i)        Dog & Cats

(1)   0.002 to 0.030 mg/kg (0.001 to 0.015 mg/lb) IV, IM, SC

(2)   0.005 to 0.020 mg/kg (0.0025 to 0.010 mg/lb) is usually very adequate for dogs and cats when combined with an opioid like butorphanol

ii)       IM protocol for cats

(1)   (25 ug/kg Medetomidine, 5 mg/kg Ketamine, 0.2 mg/kg Butorphanol)

(a)    For larger cats, consider lean body mass equivalent weight

(b)   Consider insulin syringes especially for smaller cats

(2)   IV catheters are still highly recommended

(3)   Intubation is highly recommended

(a)    Allows the easy addition of inhalant anesthetic agent should the patient be inadequately anesthetized for longer procedures

f)       Cost

i)        High (especially if atipamazole is used)

 

 

 


2)   MELOXICAM

a)      Classification

i)        A COX2 selective NSAID

b)      General Information

i)        Effective anti-inflammatory/analgesic generally free of significant GI side effects

ii)   The oral suspension is available in 1.5 mg/ml and 0.5 mg/ml concentrations

iii)  The injectable product is a 5 mg/ml concentration

c)      Advantages/Recommended use

i)        Short term use for acute pain

ii)       Long term use in chronic pain for tolerant patients

(1)   This NSAID appears more suitable for longer term use in cats

(a)    Cats, even more so than dogs, need to be monitored closely during therapy

d)      Cautionary Information

i)        As with any NSAID, GI side-effects can be substantial

(1)   Discontinue use if GI signs develop

ii)       Avoid use in:

(1)    Combination with corticosteroids

(a)    Potentially increased ulcerogenic effect

(2)   Renal compromised patients, dehydrated or hypotensive patients, patients with hepatic disease, pregnancy, patients with pre-existing GI disease, coagulopathies

iii)     Monitor liver enzymes of canine patients on chronic therapy

e)      Dosage Information

i)        Dogs

      (1)  0.2 mg/kg (0.1 mg/lb) IV, SC, PO SID on day one then 0.1 mg/kg (0.05 mg/lb) IV, SC, PO SID

ii)       Cats

(1)   Acute perioperative pain: 0.1 mg/kg to 0.2 mg/kg (0.05 to 0.1 mg/lb) SC, PO followed by 0.05 mg/kg (0.025 mg/lb) for up to 4 days if needed

(2)  Chronic pain: 

(a)   0.1 mg/kg (0.05 mg/lb) SC, PO on day 1, followed by 0.05 mg/kg (0.025 mg/lb) for up to 4 days, then reduce to lowest effective dose (0.025 mg/kg PO once every 48 to 72 hours) if long term use is required (Lascelles et al VAA 2007) Hover here for reference

(b)   0.05 mg/kg (0.025 mg/lb) SC, PO on day 1, followed by 0.025 mg/kg (0.0125 mg/lb) or less PO every 24 to 48 hours (Robertson 2008) Hover here for reference

(c)   0.01-0.03 mg/kg once daily PO (Gunew JFMS 2008) Hover here for reference

(d) 0.02 mg/kg (0.015 to 0.033 mg/kg) once daily PO (Gowan et al JFMS 2011) Hover here for reference

(3)   The injectable Metacam® product is currently labeled for a one time dose of 0.3 mg/kg (0.14 mg/lb) SC. Oral dosing following this injectable dose is not  recommended

(4)   For accurate dosing it is recommended that a Tb or insulin syringe without needle be used to draw up the exact drug volume

(5)   Exercise great caution when using NSAIDs long term in cats.

(6) For information regarding use in cats with renal disease (Gowan et al JFMS 2012) Hover here for reference

f)       Cost

i)        Moderate

 

 

 

 

3)   METHADONE

a)      Classification

i)        A pure mu opioid agonist

ii)     Methadone is felt to posses Delta opioid agonist and NMDA receptor antagonist properties1

b)      General Information

i)        Duration of effect is 4 to 6 hours

c)      Advantages/Recommended use

i)        General premed suitable for healthy animals

ii)       Most commonly used in combination with acepromazine, an alpha-2 agonist, or a benzodiazepine sedative/tranquilizer

iii)    Methadone is the least likely pure mu opioid agonist to cause nausea/vomiting

(1)   This makes methadone the mu opioid agonist best suited to preanesthetic use whenever nausea and vomiting would be considered undesirable

d)      Cautionary Information

i)        Higher dosages can cause bradycardia and respiratory depression

ii)      There is significant sedative synergism between mu agonist opioids and acepromazine in the dog

(1)   Acepromazine doses must be reduced appropriately

vi)     Should be used with caution in the cat if no sedative/tranquilizer is used

e)      Dosage Information

i)        Dog – 0.5 to 1.0 mg/kg (0.25 to 0.50 mg/lb) SC, IM, or IV

(1)   Acepromazine dose would generally be – 0.005 to 0.050 mg/kg (0.0025 to 0.025 mg/lb)

ii)       Cats – 0.25 to 0.5 mg/kg (0.125 to 0.25 mg/lb) SC, IM, or slowly IV

(1)   Acepromazine dose would generally be – 0.01 to 0.05 mg/kg (0.005 to 0.025 mg/lb)

iii)     Other uses

(1)   While its pharmacokinetics make methadone less well suited to long term constant rate infusions, infusions under 18 to 24 hours are a reasonable consideration when other pure mu agonists are not available – see section on CRIs

(2)   Epidural – not frequently used for epidurals

f)       Cost

i)        Outside the US - generally low

ii)      In the US - Very high

 

 

4)   MEXILETINE

a)      Classification

i)       

b)      General Information

i)       

c)      Advantages/Recommended use

i)       

ii)     

d)      Cautionary Information

i)       

ii)     

(1)  

vi)    

e)      Dosage Information

i)        Dog –

(1)  

ii)       Cats –

(1)  

iii)     Other uses

(1)  

f)       Cost

i)       

ii)     

 

 


5)   MIDAZOLAM

a)      Classification

i)        A benzodiazepine hypnotic sedative agent

b)      General Information

i)        Overall properties very similar to diazepam

ii)       Usually combined with ketamine or an opioid

c)      Advantages/Recommended use

i)        Similar to diazepam but can be given IM without pain and with excellent absorption

d)      Cautionary Information

i)        Given alone, can cause dysphoria, agitation, and difficult restraint

e)      Dosage Information

i)        Dogs & Cats

(1)   Generally 0.2 to 0.4 mg/kg (0.10 to 0.20 mg/lb) IV or IM

(2)   Preanesthetic Use (Choose one)

(a)    With Butorphanol 0.2 to 0.4 mg/kg (0.10 to 0.2 mg/lb) IV, IM

(b)   With Hydromorphone 0.1 to 0.2 mg/kg (0.05 to 0.1 mg/lb) IV, IM

(c)    With Oxymorphone 0.05 to 0.1 mg/kg (0.025 to 0.05 mg/lb) IV, IM

(d)   With Ketamine 2 to 10 mg/kg (1 to 5 mg/lb) IV, IM

f)       Cost

i)        Moderate

 

 

 


5)   MORPHINE SULFATE

a)      Classification

i)        A pure mu opioid agonist

b)      General Information

i)        Duration of effect is 4 to 6 hours

c)      Advantages/Recommended use

i)        General premed suitable for healthy animals

ii)       Most commonly used in combination with acepromazine, an alpha-2 agonist, or a benzodiazepine sedative/tranquilizer

iii)     May provide greater sedation than can be achieved with hydromorphone or oxymorphone

d)      Cautionary Information

i)        Higher dosages can cause bradycardia and respiratory depression

ii)       More likely to cause transient hypotensive than hydromorphone, fentanyl, or oxymorphone

iii)     Often causes vomiting and defecation when given IM or SC

iv)     IV use is associated with histamine release

(1)   This is generally considered to be a transient low level concern and is unlikely if administered slowly

v)      There is significant sedative synergism between morphine and acepromazine in the dog

(1)   Acepromazine doses must be reduced appropriately

vi)     Should be used with caution in the cat if no sedative/tranquilizer is used

e)      Dosage Information

i)        Dog – 0.5 to 1.0 mg/kg (0.25 to 0.50 mg/lb) SC, IM, or slowly IV

(1)   Acepromazine dose would be low end – 0.005 to 0.040 mg/kg (0.0025 to 0.020 mg/lb)

ii)       Cats – 0.25 to 0.5 mg/kg (0.125 to 0.25 mg/lb) SC, IM, or slowly IV

(1)   Acepromazine dose must be higher end – 0.06 to 0.1 mg/kg (0.03 to 0.05 mg/lb)

iii)     Other uses

(1)   Constant rate infusion – see section on CRIs

(2)   Epidural – see section on epidurals

f)       Cost

i)        Low

 

   
    Page References:
     
     
    http://whocancerpain.wisc.edu/?q=node/101
    http://www.ncbi.nlm.nih.gov/pubmed/12522725
    http://www.ncbi.nlm.nih.gov/pubmed/11108995
    http://www.ncbi.nlm.nih.gov/pubmed/9783723
    http://www.ncbi.nlm.nih.gov/pubmed/9058409
    http://www.ncbi.nlm.nih.gov/pubmed/14980914
    http://www.ncbi.nlm.nih.gov/pubmed/10870744
    http://www.ncbi.nlm.nih.gov/pubmed/10687335
    http://www.ncbi.nlm.nih.gov/pubmed/21906984
    http://www.ncbi.nlm.nih.gov/pubmed/22821331
     
     
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    Questions or problems regarding this web site should be directed to DRSTEIN@VASG.ORG .
Copyright © 2003 ASAH. All rights reserved.
Last modified: May 12, 2013 .
     
     
2008 Nov;38(6):1267-90, vi. doi: 10.1016/j.cvsm.2008.06.008.

Managing pain in feline patients.

Robertson SA.

Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, PO Box 100136, Gainesville, FL 32610-0136, USA. robertsons@vetmed.ufl.edu

Abstract

This article reviews the current knowledge of pain assessment in cats and the most effective methods for its alleviation. Excellent acute pain management is achievable in cats by using opioids, nonsteroidal anti-inflammatory drugs (NSAIDs), alpha(2)-agonists, and local anesthetics. A multimodal approach using agents that work at different places in the pain pathway is encouraged because this can have added benefits. Management of chronic pain in cats can be challenging, but there is now an approved NSAID for long-term use. As we gain experience with less traditional analgesics, such as gabapentin, and critically evaluate complimentary therapies, our ability to provide comfort to this population of cats should improve.

PMID: 18954684 [PubMed - indexed for MEDLINE]
2007 Jul;34(4):228-50. Epub 2007 Apr 23.

Nonsteroidal anti-inflammatory drugs in cats: a review.

Lascelles BD, Court MH, Hardie EM, Robertson SA.

Comparative Pain Research Laboratory, Department of Clinical Sciences, North Carolina State University, Raleigh, NC 27606, USA. duncan_lascelles@ncsu.edu

Abstract

OBJECTIVE:

To review the evidence regarding the use of nonsteroidal anti-inflammatory drugs (NSAIDs) in cats.

DATABASES USED:

PubMed, CAB abstracts.

CONCLUSIONS:

Nonsteroidal anti-inflammatory drugs should be used with caution in cats because of their low capacity for hepatic glucuronidation, which is the major mechanism of metabolism and excretion for this category of drugs. However, the evidence presented supports the short-term use of carprofen, flunixin, ketoprofen, meloxicam and tolfenamic acid as analgesics in cats. There were no data to support the safe chronic use of NSAIDs in cats.

Comment in

PMID: 17451496 [PubMed - indexed for MEDLINE]
2008 Jul;10(3):235-41. doi: 10.1016/j.jfms.2007.10.007. Epub 2008 Apr 28.

Long-term safety, efficacy and palatability of oral meloxicam at 0.01-0.03 mg/kg for treatment of osteoarthritic pain in cats.

Gunew MN, Menrath VH, Marshall RD.

The Cat Clinic Mt Gravatt, Mt Gravatt, QLD, Australia. mgunew@optusnet.com.au

Abstract

Osteoarthritis is a chronic, painful condition that is now recognised as affecting a large proportion of cats. Non-steroidal anti-inflammatory drugs (NSAIDs) have proven efficacy in dogs and humans but there are limited published data on the use of NSAIDs in the long-term management of this condition in cats. This prospective study aimed to assess the long-term safety and palatability of oral meloxicam and its efficacy in treating osteoarthritic pain in cats when given at a dose of 0.01-0.03 mg/kg once daily. Forty cats diagnosed with osteoarthritis completed the trial with a mean treatment duration of 5.8 months. Gastrointestinal upset in 2/46 (4%) cats was the only adverse effect noted. No deleterious effect on renal function was detected in cats studied. Owners subjectively assessed treatment efficacy as good or excellent in 34/40 (85%) of cases. The results of this study showed oral meloxicam to be safe and palatable long-term treatment for osteoarthritis in cats when given with food at a dose of 0.01-0.03 mg/kg.

PMID: 18440263 [PubMed - indexed for MEDLINE]
2012 Dec;14(12):876-81. doi: 10.1177/1098612X12454418. Epub 2012 Jul 20.

A retrospective analysis of the effects of meloxicam on the longevity of aged cats with and without overt chronic kidney disease.

Gowan RA, Baral RM, Lingard AE, Catt MJ, Stansen W, Johnston L, Malik R.

The Cat Clinic, 1 Miller Street, Prahran, Melbourne, Australia. info@catdoctor.com.au

Abstract

The study sought to examine the effect of long-term meloxicam treatment on the survival of cats with and without naturally-occurring chronic kidney disease at the initiation of therapy. The databases of two feline-only clinics were searched for cats older than 7 years that had been treated continuously with meloxicam for a period of longer than 6 months. Only cats with complete medical records available for review were recruited into the study.The median longevity in the renal group was 18.6 years [95% confidence interval (CI) 17.5-19.2] and the non-renal group was 22 years [95% CI 18.5-23.8]. The median longevity after diagnosis of CKD was 1608 days [95% confidence interval 1344-1919] which compares favourably to previously published survival times of cats with CKD. In both groups the most common cause of death was neoplasia. Long-term treatment with oral meloxicam did not appear to reduce the lifespan of cats with pre-existent stable CKD, even for cats in IRIS stages II and III. Therefore, to address the need for both quality of life and longevity in cats with chronic painful conditions, meloxicam should be considered as a part of the therapeutic regimen.

PMID: 22821331 [PubMed - in process]
2011 Oct;13(10):752-61. doi: 10.1016/j.jfms.2011.06.008. Epub 2011 Sep 9.

Retrospective case-control study of the effects of long-term dosing with meloxicam on renal function in aged cats with degenerative joint disease.

Gowan RA, Lingard AE, Johnston L, Stansen W, Brown SA, Malik R.

The Cat Clinic, Prahran, Melbourne, Australia. rgowan75@gmail.com

Abstract

Medical records (2005-2009) of a feline-only practice were searched for cats with degenerative joint disease (DJD) treated using meloxicam. DJD was diagnosed by the presence of at least two of the following: (i) altered mobility (observed by the owner), (ii) abnormal physical findings, (iii) characteristic radiographic changes. The primary study cohort consisted of cats older than 7 years that had received meloxicam for variable intervals in excess of 6 months, and for which complete records were available. These cats were subdivided according to whether detectable chronic kidney disease (CKD) was present ('renal group'), or not ('non-renal group'), and, for the 'renal group', according to the cat's IRIS category. Serum biochemistry, urinalysis (including urine specific gravity [USG]), body mass and condition score were monitored regularly. Progression of CKD in the 'renal group' and 'non-renal group' of cats was compared to two groups of age- and IRIS-matched control cats not receiving meloxicam (from the same clinic, over the same time period). The study was thus a case-control design, with two study groups. Thirty-eight cats with DJD receiving long-term meloxicam therapy met the inclusion criteria. Of these, 22 cats had stable CKD at the start of treatment (stage 1, eight cats; stage 2, 13 cats; stage 3, one cat). No cats initially had an elevated urinary protein to creatinine ratio. The remaining 16 cats initially had normal renal analytes and adequately concentrated urine. The median age of the 'renal' and 'non-renal' meloxicam groups was 15.5 and 13.4 years, respectively. The median treatment duration was 467 days in the 'renal group' and 327 days in the 'non-renal group'. After titration (to the lowest effective dose), the median maintenance dose was 0.02 mg/kg/day in both groups (range 0.015-0.033 mg/kg/day). There was no difference in sequential serum creatinine concentration or USG measurements between the 'non-renal group' treated with meloxicam compared to control cats not treated with meloxicam. There was less progression of renal disease in the 'renal group' treated with meloxicam compared to the age- and IRIS-matched cats with CKD not given meloxicam. These results suggest that a long-term maintenance dose of 0.02 mg/kg of meloxicam can be safely administered to cats older than 7 years even if they have CKD, provided their overall clinical status is stable. Long-term meloxicam therapy may slow the progression of renal disease in some cats suffering from both CKD and DJD. Prospective studies are required to confirm these findings.

Copyright © 2011 ISFM and AAFP. Published by Elsevier Ltd. All rights reserved.

PMID: 21906984 [PubMed - indexed for MEDLINE]