1)   Acepromazine (only)

a)      General information

i)                    A phenothiazine tranquilizer

(1)   Acepromazine has no direct analgesic properties

ii)                  Acepromazine can be used alone, as a premedicant. However, it is more effective to use Acepromazine in combination with an opioid narcotic agent.

(a)    The addition of an opioid reduces acepromazine dose, and therefore also reduce the likelihood of hypotension or sustained, excessive sedation that can occur.

b)      Patient selection

i)                    Recommended use

(1)   Use of acepromazine as a sole agent is not recommended

2)   Acepromazine & Butorphanol

a)      General information

i)                    Combination of a phenothiazine tranquilizer and an opioid

ii)                  Butorphanol adds a short acting analgesic effect

iii)                 The synergistic effect of these two agents allows for a substantial reduction in the acepromazine need, reducing the likelihood of hypotension or sustained, excessive sedation that can occur

b)      Patient selection

i)                    Recommended use

(1)   Healthy animals in the Good to Excellent category

(2)   Larger, calmer, older patients require much lower acepromazine doses

(3)   Smaller, stressed, younger patients may require higher acepromazine doses

ii)                  Cautionary information

(1)   Avoid if:

(a)    History of seizures

(i)      Some anesthesiologists feel that seizures are of minimal concern at usual clinical doses

(b)   Geriatric

(i)      It is generally recommended to avoid acepromazine in geriatric patients. Substantially lower doses are adequate in patients 7 years of age or older

(c)    Debilitated

(d)   Liver dysfunction

(e)    Anemic

(f)     Hypotensive

(g)    Hypovolemic

(h)    Known patient sensitivity exists

(2)   Butorphanol has an antagonistic effect when used with mu agonist opioids such as morphine, hydromorphone, fentanyl, or oxymorphone

c)      Dosage

i)                    Diluting 10 mg/ml acepromazine to 1 or 2 mg/ml helps facilitate more accurate dosing, especially when managing smaller patients

(1)   For 2 mg/ml concentration - inject 2 cc of 10 mg/ml acepromazine and 8 cc of sterile water into a sterile vial to produce 2 mg/ml acepromazine

(2)   For 1 mg/ml concentration - inject 1 cc of 10 mg/ml acepromazine and 9 cc of sterile water into a sterile vial to produce 1 mg/ml acepromazine

(3)   Alternatively, when using 10 mg/ml acepromazine, measure drug doses utilizing U-100 1/3 cc insulin syringes

ii)                  Dog

(1)   Acepromazine            0.005 to 0.060 mg/kg (0.0025 to 0.03 mg/lb)

(a)    2.0 to 3.0 mg are frequently recommended maximum total dosages regardless of weight

(2)   Butorphanol            0.1 to 0.4 mg/kg (0.05 to 0.2 mg/lb)

(a)    0.1 mg/lb is usually adequate for most patients

(b)   Higher dosages do not result in better analgesia and excitation can occur.

iii)                 Cat

(1)   Acepromazine            0.04 to 0.10 mg/kg (0.02 to 0.05 mg/lb)

(2)   Butorphanol            0.10 to 0.40 mg/kg (0.05 to 0.2 mg/lb)

(a)    0.1 mg/lb is usually adequate for most patients

iv)                Route of administration

(1)   IV/IM/SC use

(a)    IV has a more rapid and profound effect

(i)      Use the lower end of the dose range for both agents when administering this combination IV

(b)   IM has a moderately rapid, moderately profound effect but is painful

(c)    SC is less painful though the effect is slower and less profound

d)      General Cost Category

i)                    Moderate - acepromazine is inexpensive but butorphanol is of moderate expensive especially for larger dogs

3)   Acepromazine & a pure mu agonist Opioid

a)      General information

i)                    Combination of phenothiazine tranquilizer and fentanyl, hydromorphone, methadone, morphine, or oxymorphone

ii)                  Compared to acepromazine & butorphanol, this combination provides somewhat greater sedation in dogs and a stronger analgesic influence of longer duration in both dogs and cats

iii)                 Less sedative synergism exists between acepromazine and hydromorphone in dogs when compared to the sedative synergism that exists between acepromazine and morphine in dogs (see below)

iv)                Medetomidine may produce more consistent sedation and relaxation than acepromazine when combined with the mu opioids in cats

b)      Patient selection

i)                    Recommended use

(1)   Generally for healthy animals in the Good to Excellent category

(2)   Larger, calmer, older patients may require much lower acepromazine doses

(3)   Smaller, stressed, younger patients may require higher acepromazine doses

ii)                  Cautionary Information

(1)   All mu agonists can cause bradycardia and respiratory depression

(2)   Morphine and hydromorphone commonly cause vomition regardless of route

(a)    Oxymorphone is less likely to cause vomition regardless of route

(3)   Histamine release: morphine can cause a histamine release which may cause a transient hypotensive effect

(a)    This is more likely with IV use and is unlikely when morphine is given IM or SC

(4)   Mu agonists may cause a mild, transient hyperthermia in cats

(5)   Avoid acepromazine if:

(a)    History of seizures

(i)      Some anesthesiologists feel that seizures are of minimal concern at usual clinical acepromazine doses

(b)   Geriatric

(i)      It is generally recommended that acepromazine be avoided in geriatric patients. When used in older patients, substantially lower doses may be adequate

(c)    Debilitated

(d)   Liver dysfunction

(e)    Anemic

(f)     Hypotensive

(g)    Hypovolemic

(h)    Known patient sensitivity exists

c)      Dosage

i)                    Dog

(1)   Acepromazine                        0.010 to 0.060 mg/kg (0.005 to 0.03 mg/lb)

(a)    2.0 to 3.0 mg are frequently recommended maximum total dosages regardless of weight

(2)   One of the following opioids:

(a)    Hydromorphone      0.10 to 0.20 mg/kg (0.05 to 0.10 mg/lb)

(b)   Oxymorphone      0.05 to 0.10 mg/kg (0.025 to 0.05 mg/lb)

(c)    Morphine            0.50 to 1.0 mg/kg (0.25 to 0.50 mg/lb)

(d)   Fentanyl            0.005 to 0.010 mg/kg (0.0025 to 0.005 mg/lb)

ii)                  Cat

(1)   Acepromazine                        0.04 to 0.10 mg/kg (0.02 to 0.05 mg/lb)

(a)    Most common dose is 0.06 to 0.10 mg/kg (0.03 to 0.05 mg/lb) for cats

(b)   Higher acepromazine dose may be needed for cats when combining acepromazine with a mu agonist as mu agonists have an excitatory influence on cats which contrasts with the mu agonists sedative affect on dogs

(2)   One of the following opioids:

(a)    Hydromorphone      0.10 to 0.20 mg/kg (0.05 to 0.10 mg/lb)

(b)   Oxymorphone      0.05 to 0.10 mg/kg (0.025 to 0.05 mg/lb)

(c)    Morphine            0.50 to 1.0 mg/kg (0.25 to 0.50 mg/lb)

(d)   Fentanyl            0.005 to 0.010 mg/kg (0.0025 to 0.005 mg/lb)

(i)      The lower end of the opioid dose range is usually adequate for cats

iii)                 Routes of administration

(1)   IV/IM/SC use

(2)   IV has a very rapid and profound effect

(i)      Use the lower end of the dose range for both agents when administering this combination IV

(3)   IM has a moderately rapid, moderately profound effect but is painful

(4)   SC somewhat less painful and somewhat slower, less profound effect

d)      General Cost Category

i)                    Low

4)   Buprenorphine (only)

a)      General information

i)                    Mixed agonist/antagonist opioid of moderately long duration depending on dose

(1)   Agonistic effect at mu opioid receptor

(2)   Extremely high receptor affinity gives buprenorphine an antagonistic effect when mixed with pure mu opioids like hydromorphone, oxymorphone, morphine, or fentanyl which may be a strategic advantage

ii)                  Dose has significant influence on duration of effect but no influence on degree of analgesia

iii)                 Undesirable effects are rare

iv)                Minimal sedation, limited reversibility, and moderate cost make this less attractive as a single agent premed

v)                  There is a significantly delayed time of onset

(1)   30 minutes when given IV

(2)   45 to 60 minutes when given IM

(3)   SC use is not recommended

b)      Patient selection

i)                    Recommended use

(1)   Aging or debilitated patients where an analgesic effect is desired but sedation is not

(2)   Routine surgeries and procedures that are not associated with severe pain

ii)                  Cautionary information

(1)   Extremely high affinity makes this opioid difficult to reverse

c)      Dosage

i)                    Dogs      0.010 to 0.040 mg/kg (0.005 – 0.020 mg/lb)

ii)                  Cats       0.010 to 0.040 mg/kg (0.005 – 0.020 mg/lb)

iii)                 The dose influences the duration of effect but not the degree of analgesia

(1)   0.010 mg/kg                                    4 to 6 hour duration

(2)   0.020 mg/kg                                    6 to 8 hour duration

(3)   0.030 to 0.040 mg/kg                        10 to 12 hour duration

iv)                Routes of administration

(1)   IV or IM

(2)   SC use is not recommended

d)      General Cost Category

i)                    Moderate to high depending on dose

5)   Butorphanol (only)

a)      General Description

i)                    Mixed agonist/antagonist opioid with short duration and very mild sedative effects

(1)   Agonistic effect at Kappa and sigma opioid receptors

(2)   Antagonistic effect at the mu receptor which may be a strategic advantage

(3)   Reversibility is a subject of debate

b)      Patient selection

i)                    Recommended use

(1)   In patients where:

(a)    Acepromazine use is a concern

(b)   Some analgesia and mild sedation is desired

(c)    A mu agonist is not necessary or is of a concern

ii)                  Cautionary information

(1)   The duration of analgesic effect is very short

(a)    45 to 60 minutes in the dog

(b)   60 to 90 minutes in the cat

(2)   Will antagonize mu agonists if given concurrently

c)      Dosage

i)                    Dog        0.10 to 0.40 mg/kg (0.05 to 0.2 mg/lb)

ii)                  Cat         0.10 to 0.40 mg/kg (0.05 to 0.2 mg/lb)

iii)                 Increased dosages are NOT associated with an increase in analgesia

(1)   Doses exceeding 0.4 mg/kg (0.2 mg/lb) can cause undesirable excitatory effects

iv)                Routes of administration

(1)   IV, IM, or SC

d)      General Cost Category

i)                    Moderate

6)   Hydromorphone (only)

a)      General information

i)                    Mu opioid agonist of moderate duration

ii)                  Same properties as oxymorphone although ½ the potency and it is much less costly

(1)   Vomition occurs more commonly than with oxymorphone

(2)   Noise sensitivity is not as likely with hydromorphone when compared to oxymorphone

b)      Patient selection

i)                    Recommended use

(1)   Higher risk patients

ii)                  Cautionary information

(1)   See ace/opioid combinations above

(2)   Cat usually experience excitatory effects when given mu agonists alone

c)      Dosage

i)                    Dogs       0.10 to 0.20 mg/kg (0.05 to 0.10 mg/lb)

ii)                  Cats        not recommended as a sole agent

iii)                 Routes of administration

(1)   IV, IM, or SC

d)      General Cost Category

i)                    Low

7)   Medetomidine

a)      General Description

i)                    Alpha-2 agonist

ii)                  Medetomidine can be used alone, however it is often combined with an opioid for a synergistic effect.

(1)   Addition of an opioid allows a reduction of the Medetomidine dose and reduces the likelihood of the more dramatic negative cardiovascular effects that alpha-2 agonists can cause

iii)                 Substantially reduces induction agent need

iv)                Potent sedative and analgesic

v)                  Effects can be completely reversed using atipamazole

(1)   The more complete the sedation reversal, the more complete the reversal of the analgesic effect

(2)   Partially reversing the agent may allow you to retain some of the analgesic benefit of the drug

b)      Patient selection

i)                    Recommended use

(1)   Normal, young, healthy patients in the excellent category

ii)                  Cautionary information

(1)   Use of medetomidine in older or more debilitated patients requires significant reductions in dosage and more vigilant attention the patient’s cardiovascular status

(2)   Stressed patients may not respond as well

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

(b)   Additional medetomidine may be given after 20 minutes if further sedation is required

iii)                 Can cause bradycardia

(1)   Anticholinergic use is controversial

c)      Dosage

i)                    Dogs       0.002 to 0.040 mg/kg (0.001 to 0.020 mg/lb)

(a)    Doses above 0.020 mg/kg (0.010 mg/lb) should be used with careful attention to patient selection

ii)                  Cats        0.002 to 0.040 mg/kg (0.001 to 0.020 mg/lb)

(a)    Doses above 0.020 mg/kg (0.010 mg/lb) should be used with careful attention to patient selection

iii)                 Routes of administration

(1)   IV/IM use

(a)    IV has a much more rapid and profound effect

(i)      Use lower doses - approximately 50% of the dose you would consider giving IM

(b)   The epaxial muscles are the preferred site of injection for more predictable drug absorption

(i)      Needles of appropriate length to penetrate through subcutaneous fat and into muscle must be selected. Larger dogs will commonly require a 1½” needle

d)      General Cost Category

i)                    High – especially if reversal agent, atipamazole, is used

8)   Medetomidine & Butorphanol

a)      General Description

i)                    An alpha-2 agonist and opioid agent

(1)   The synergistc effect of these two agents allows for a substantial reduction in the medetomidine dosage, thereby reducing the likelihood of the more dramatic negative cardiovascular effects that alpha-2 agonists can cause

ii)                  Substantially reduces induction agent need

iii)                 Potent sedative and analgesic effects

iv)                Effects can be substantially reversed using atipamazole

(1)   The more complete the sedation reversal, the more complete the reversal of the analgesic effects

(2)   Partially reversing the medetomidine may allow you to retain some of the analgesic benefit of the drug

v)                  Provides good relaxation and analgesia when used in young, healthy cats

b)      Patient selection

i)                    Recommended use:

(1)   Normal, young, healthy patients in the excellent category

ii)                  Cautionary information

(1)   Use of medetomidine in older or more debilitated patients requires significant reductions in dosage and more vigilant attention the patient’s cardiovascular status

(2)   Stressed patients may not respond as well

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

(b)   Additional medetomidine may be given after 20 minutes if further sedation is required

iii)                 Can cause bradycardia

(1)   Anticholinergic use is controversial

c)      Dosage

i)                    Dogs

(1)   Medetomidine                        0.002 to 0.040 mg/kg (0.001 to 0.020 mg/lb)

(a)    Doses above 0.020 mg/kg (0.010 mg/lb) should be used with careful attention to patient selection

(2)   Butorphanol                        0.10 to 0.40 mg/kg (0.05 to 0.2 mg/lb)

ii)                  Cats

(1)   Same as the dogs

iii)                 Routes of administration

(1)   IV/IM use

(a)    IV has a much more rapid and profound effect

(i)      Use lower doses - approximately 50% of the dose you would consider giving IM

(b)   The epaxial muscles are the preferred site of injection for more predictable drug absorption

(i)      Needles of appropriate length to penetrate through subcutaneous fat and into muscle must be selected. Larger dogs will commonly require a 1½” needle

d)      General Cost Category

i)                    High – especially if reversal agent, atipamazole, is used

9)   Medetomidine & a pure mu agonist Opioid

a)      General Description

i)                    An alpha-2 agonist and fentanyl, hydromorphone, methadone, morphine, or oxymorphone

(1)   The synergistc effect of these two agents allows for a substantial reduction in the medetomidine dosage thereby reducing the likelihood of the more dramatic negative cardiovascular effects that alpha-2 agonists can cause

ii)                  Substantially reduces induction agent need

iii)                 Potent sedative and analgesic effects

iv)                Effects can be completely reversed using atipamazole and naloxone

(1)   The more complete the sedation reversal, the more complete the reversal of the analgesic effects

(2)   Partially reversing the agents may allow you to retain some of the analgesic benefit of the drugs

b)      Patient selection

i)                    Recommended use:

(1)   Normal, young, healthy patients in the excellent category

ii)                  Cautionary information

(1)   Use of medetomidine in older or more debilitated patients requires significant reductions in dosage and more vigilant attention the patient’s cardiovascular status

(2)   Stressed patients may not respond as well

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

(b)   Additional medetomidine may be given after 20 minutes if further sedation is required

iii)                 Can cause bradycardia

(1)   Bradycardia may be more profound than with medetomidine alone

(2)   While the use of anticholinergic is still controversial, the addition of the opioid often justifies the use of anticholinergics.

c)      Dosage

i)                    Dogs

(1)   Medetomidine                        0.002 to 0.040 mg/kg (0.001 to 0.020 mg/lb)

(a)    Doses above 0.020 mg/kg (0.010 mg/lb) should be used with careful attention to patient selection

(2)   One of the following opioids:

(a)    Hydromorphone      0.10 to 0.20 mg/kg (0.05 to 0.10 mg/lb)

(b)   Oxymorphone      0.05 to 0.10 mg/kg (0.025 to 0.05 mg/lb)

(c)    Morphine            0.50 to 1.0 mg/kg (0.25 to 0.50 mg/lb)

(d)   Fentanyl            0.005 to 0.010 mg/kg (0.0025 to 0.005 mg/lb)

ii)                  Cats

(a)    Same as the dogs

(i)      Use the lower end of the opioid dose range above

iii)                 Routes of administration

(1)   IV/IM use

(a)    IV has a much more rapid and profound effect

(i)      Use lower doses - approximately 50% of the dose you would consider giving IM

(b)   The epaxial muscles are the preferred site of injection for more predictable drug absorption

(i)      Needles of appropriate length to penetrate through subcutaneous fat and into muscle must be selected. Larger dogs will commonly require a 1½” needle

d)      General Cost Category

i)                    High – especially if reversal agent, atipamazole, is used

10)          Midazolam (only)

a)      General Description

i)                    Benzodiazepine (as is diazepam)

(1)   Unlike diazepam, midazolam is quickly and predictably absorbed when given by the IM route.

ii)                  Of little use as a sole agent due to minimal sedation in normal healthy adult patients

(1)   Generally combined with an opioid or ketamine

b)      Patient selection

i)                    Recommended use

(1)   Can reduce induction agent need in dogs

ii)                  Cautionary information

(1)   When used alone may cause nervousness and excitement in cats

c)      Dosage

i)                    Dogs       0.10 to 0.20 mg/kg (0.05 to 0.10 mg/lb)

ii)                  Cats        not recommended

(1)   Used alone, can cause nervousness and excitement in cats

iii)                 Routes of administration

(1)   IV or IM use

d)      General Cost Category

i)                    Moderate

11)          Midazolam & Butorphanol

a)      General information

i)                    A benzodiazepine and an opioid agent

b)      Patient selection

i)                    Recommended use

(1)   Higher risk patients:

(a)    Cardiac disease

(b)   Debilitation 

ii)                  Cautionary information

(1)   Generally not suitable if heavy sedation is desired

(2)   The duration of analgesic effect is very short

(a)    45 to 60 minutes in the dog

(b)   60 to 90 minutes in the cat

c)      Dosage

i)                    Dogs

(1)   Midazolam            0.10 to 0.20 mg/kg (0.05 to 0.10 mg/lb)

(2)    Butorphanol            0.10 to 0.40 mg/kg (0.05 to 0.2 mg/lb)

ii)                  Cats

(1)   Same as the dogs

iii)                 Routes of administration

(1)   IV or IM use

d)      General Cost Category

i)                    Moderate

12)          Midazolam & a pure mu agonist Opioid

a)      General Description

i)                    A benzodiazepine and fentanyl, hydromorphone, methadone, morphine, or oxymorphone

b)      Patient selection

i)                    Recommended use

(1)   Higher risk patients:

(a)    Cardiac disease

(b)   Debilitation 

ii)                  Cautionary information

(1)   Generally not suitable if heavy sedation is desired

(2)   Can cause bradycardia and respiratory depression due to the opioid

(3)   Use mu agonists with caution if vomition is considered a significant risk

c)      Dosage

i)                    Dogs

(1)   Midazolam                        0.10 to 0.20 mg/kg (0.05 to 0.10 mg/lb)

(2)   One of the following opioids

(a)    Hydromorphone      0.10 to 0.20 mg/kg (0.05 to 0.10 mg/lb)

(b)   Oxymorphone      0.05 to 0.10 mg/kg (0.025 to 0.05 mg/lb)

(c)    Morphine            0.50 to 1.0 mg/kg (0.25 to 0.50 mg/lb)

(d)   Fentanyl            0.005 to 0.010 mg/kg (0.0025 to 0.005 mg/lb)

ii)                  Cats

(a)    Same as the dogs

(i)      Use the lower end of the opioid dose range above

iii)                 Routes of administration

(1)   IV or IM use

d)      General Cost Category

i)                    Moderate

13)          Morphine (only)

a)      General Description

i)                    A pure mu opioid agonist

b)      Patient selection

i)                    Recommended use

(1)   Suitable for healthy animals

(a)    Most commonly used in combination with acepromazine or another sedative/tranquilizer

(2)   When greater sedation than can be achieved with hydromorphone or oxymorphone is desired

ii)                  Cautionary information

(1)   Histamine release: morphine can cause a histamine release which may cause a transient hypotensive effect

(a)    This is more likely with IV use and is unlikely when morphine is given IM or SC

(2)   Often causes vomiting and defecation

(3)   Higher dosages can cause bradycardia and respiratory depression

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

c)      Dosage

i)                    Dog        0.5 to 1.0 mg/kg (0.25 to 0.5 mg/lb)

ii)                  Cat         not recommended except as a low dose CRI

(1)   Should be combined with acepromazine to avoid hypersensitivity

iii)                 Routes of administration

(1)   IV/IM/SC use

(a)    IV injections should be given slowly to minimize the potential for a histamine mediated hypotensive effect

d)      General Cost Category

i)                    Low

14)          Oxymorphone (only)

a)      General Description

i)                    A pure Mu opioid agonist

b)      Patient selection

i)                    Recommended use

(1)   Similar to the other the other mu agonists

(2)   Higher risk patient when the risk of vomiting needs to be minimized

(3)   Hypotensive patients

ii)                  Cautionary information

(1)   Similar to the other the other mu agonists

(a)    Histamine release is not expected with oxymorphone

(2)   Noise hypersensitivity may be a problem

c)      Dosage

i)                    Dog        0.05 to 0.10 mg/kg (0.025 to 0.05 mg/lb)

ii)                  Cats        0.025 to 0.10 mg/kg (0.0125 to 0.05 mg/lb)

iii)                 Routes of administration

(1)   IV/IM/SC use

d)      General Cost Category

i)                    Moderate