Page 91 - JSOM Winter 2017

of canines exposed to heroin were similar to fentanyl. Consider- Table 1 Recommended Actions When Treating an Exposed OpK9
ing many field exposures in OpK9s undoubtedly go unreported • Activate EMS response system, perform a scene survey, and ensure
to the animal poison helplines, the true epidemiology of out-of- scene safety:
hospital illicit opioid exposures in OpK9s remains uncertain. o Avoid self-exposure to opioids and cross-contamination while
handling the OpK9.
o Take appropriate personal protection actions and don PPE
A challenge facing handlers, first responders, and veterinary per- (nitrile gloves, N-95, dust mask, eye protection, paper coveralls,
sonnel is knowing exactly what drug(s), if any, the OpK9 may and shoe covers).
have been exposed to. Because opioids are mixed with other • Support ABCs (establish patent airway, support ventilation, move
nonopioid illicit agents (e.g., cocaine, methamphetamines, and into fresh air, provide oxygen supplementation as needed, initiate
others), an OpK9 may develop clinical manifestations related CPR if in cardiac arrest):
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o If rescue breathing is warranted, AVOID mouth-to-snout.
to the other compounds in the mixture. These clinical signs Instead, use a bag-valve-mask with a canine-specific face mask.
may be atypical and opposing that of an opioid overdose (e.g., o OpK9s with no pulse may be in cardiac arrest or may have
methamphetamine produces fast heart rates [tachycardia], high an undetected weak or slow pulse. Manage as cardiac arrest
blood pressure [hypertension] agitation/aggression, increased patients. See Recommended Internet Resources for veterinary
CPR guidelines.
body temperature [hyperthermia), and convulsions). This un- • When feasible, thoroughly wash powder or agent off the OpK9’s
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certainty may detrimentally delay appropropriate and timely hair coat and skin and out of his or her eyes and mouth:
treatment and personal protective actions. o Avoid interventions that may enhance transdermal absorption
(e.g., alcohol-based hand sanitizers, alcohol, and warm-to-hot
water).
Role of Naloxone in the Treatment of Opioid Toxicity o After washing drug/agent off OpK9, take actions to dry and
keep the OpK9 warm (e.g., cover with blanket, sheet, etc.).
Naloxone is a standard drug carried by EMS providers and o If washing the K9 is not feasible, consider wrapping the
hospital emergency departments (human and veterinary) for OpK9 in a sheet, blanket, or other similar material to mitigate
dispersion of powder off the OpK9’s hair coat.
treating accidental or intentional opioid overdoses. It is one • Administer naloxone (see dose recommendations listed earlier)
component of a larger stabilization protocol for managing when exposure is known or highly suspect and the OpK9 is
opioid toxicity (Table 1). Naloxone is a reversible competitive displaying clinical signs such as:
antagonist of μ, δ, and κ OP receptors. It has greater activity at o Unresponsive or altered mental status
the MOP than the δ and κ OPs. As a competitive antagonist, o Slow or absent breathing or gasping breaths
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sufficient concentrations of naloxone are required to displace o Slow (<50 bpm) heart/pulse rate and weak femoral pulse quality
o Weakness or staggering
the already bound MOP agonists (e.g., morphine, fentanyl, o Pinpoint pupils
carfentanil, and others) as well as prevent further agonist o Dysphoria (vocalizing, agitation, appearing frantic) may be an
binding to the MOP. early indicator of exposure
NOTE: When in doubt, administer naloxone.
• Repeat naloxone as needed. Perform serial reassessments.
The two definitive clinical indications for naloxone adminis- • Seek immediate veterinary medical attention even if OpK9
tration in people and OpK9s include 14,32,46 : positively responds to naloxone administration. Never leave an
exposed OpK9 unattended as OpK9s have a high likelihood of
• Altered mental status (markedly sedated to unresponsive) experiencing renarcotization.
• Very slow, absent, or gasping breathing (i.e., fewer than six WARNING: After administering naloxone, expect the OpK9 to
to eight breathes per minute with shallow chest excursions) rapidly awake from their state of drug-induced stupor in which they
may still be disoriented and be in a ‘protective/defensive’ mode.
• OpK9s may want to bite/attack anything in the immediate
Opioid exposure alone does not always warrant naloxone vicinity, to include the handler.
administration. In canines, opioid overdose is most often • OpK9s should be properly restrained and/or have an open
manifested only by excessive sedation, bradycardia, and hy- basket muzzle secured in place before or immediately after
pothermia. Although these cases do not always require nal- administering naloxone.
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oxone, it may prove more prudent to administer naloxone as
soon as signs of toxicity appear, particularly since naloxone • Repeat doses: Administer additional doses of naloxone as
has few to little adverse effects when administered in canines. 32 needed based on clinical signs.
SPECIAL NOTE: Two or more doses of naloxone are likely
Recommended Naloxone Doses and Administration required en route to the veterinary facility. Naloxone’s dura-
The initial recommended IV, IM, and SC adult human dose in tion of action is often shorter than that of the illicit opioid
a known or suspected opioid overdose is 0.4 to 2mg; this may encountered. 30,32,47 Recurrence of clinical sign (renarcotization)
be repeated to a total dose of 10mg. Intranasal (IN) dosing is a high possibility, particularly when an OpK9 is exposed to
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for humans is dependent on the product used (refer to link for a long-acting opioid or to a large amount of a short-acting
“Naloxone Product Chart” listed under Recommended Inter- opioid. Renarcotization is common with carfentanil exposures
net Resources). Based on current available data, the following where it is reported that human carfentanil exposures require
are recommendations for initial naloxone dosing in OpK9s: higher and more frequent naloxone dosing than that typically
used for a routine fentanyl or heroin intoxication. 15,50
• IV/IO: 0.01 to 0.04mg/kg (1–2mg per 25 kg) 30,49
• IM: 0.04 to 0.16mg/kg (2–4mg per 25 kg) 30
• IN: 2 to 4mg per 25 kg OpK9 Safety Concerns With Naloxone Administration
• OTM (buccal pouch): Use IN dosing recommendations. Naloxone has a very wide margin of safety in canines. 30,47 In
Consider as a last resort if no other route is available canines that have not been exposed to an opioid, naloxone ex-
(e.g., cannot establish IV/IO access and IM or IN [blocked erts no pharmacologic agonistic effect. 48,51 As such, even with
nasal cavity, excess nasal discharge, etc.] administraton using the high-end recommended dose, naloxone is unlikely
unavailable). to result in any significant adverse effects. Although naloxone

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