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50 Amphetamine Toxicosis

Amphetamine Toxicosis Client Education
Sheet
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• Rhabdomyolysis from increased motor
BASIC INFORMATION
effect
activity can cause myoglobinuria with sec- ○ Chlorpromazine 0.5 mg/kg IV, titrate to
Definition ondary kidney injury (p. 1367). ○ Cyproheptadine: dogs: 1.1 mg/kg; cats:
Amphetamines result in central nervous system • Increased muscular activity can cause 2-4 mg/CAT PO or crushed in saline and
(CNS) and cardiovascular (CV) stimulation. hyperthermia with secondary complications given rectally for signs of serotonin
Toxicosis is typically caused by ingestion of (p. 421). syndrome
prescription attention deficit disorder/attention ○ Minimize sensory stimuli
deficit hyperactivity disorder (ADD/ADHD) DIAGNOSIS • Thermoregulation
medication or illicit drugs (e.g., methamphet- ○ Control stimulatory signs
amine, ecstasy [MDMA]). Diagnostic Overview ○ Fans, cool towels, IV crystalloid fluids
Although confirmatory tests exist, diagnosis is prn
Epidemiology typically based on evidence of exposure to • Cardiac arrhythmias
SPECIES, AGE, SEX amphetamines and/or consistent clinical signs. ○ Sinus tachycardia in a calm pet
Dogs and young animals are overrepresented ■ Propranolol 0.02-0.06 mg/kg IV, titrate
because they are more likely to ingest nonfood Differential Diagnosis slowly to effect, or
items. Toxins: 5-Hydroxytryptophan; pseudoephedrine, ■ Esmolol 25-200 mcg/kg/minute CRI
phenylephrine, ephedrine; nicotine; albuterol; ○ Ventricular tachyarrhythmias
RISK FACTORS cocaine; phenylpropanolamine; caffeine or other ■ Lidocaine 1-4 mg/kg IV, followed by
• Presence of amphetamines in the household methylxanthines (chocolate); guarana CRI of 25-80 mcg/kg/min CRI, if
• The drugs are often prescribed to children, needed
who may be more likely to leave them out Initial Database • Antiepileptics
where pets can get to them. • CBC, serum chemistry profile, and ○ Diazepam 0.5-2 mg/kg IV; benzodiaze-
urinalysis: nonspecific; possible findings pines can be used for seizure control but
GEOGRAPHY AND SEASONALITY include myoglobinuria, azotemia due to should be avoided for other uses because
An increase in exposures is reported in acute kidney injury, hypoglycemia, or it can worsen the stimulatory signs, or
the fall, when children are going back to thrombocytopenia if hyperthermia leads to ○ Phenobarbital 3-4 mg/kg IV, or
school. secondary coagulopathy ○ Gas anesthesia or propofol: refractory
• Coagulation profile: if coagulopathy is seizures
Clinical Presentation suspected • Generalized muscle tremors
DISEASE FORMS/SUBTYPES • Acid base status: metabolic acidosis and com- ○ Methocarbamol 55-220 mg/kg slow IV
Ingestion of extended-release prescription pensatory respiratory alkalosis is common. to effect
medications can have a delayed onset of clinical • Fluid diuresis
signs. Advanced or Confirmatory Testing • Vomiting, nausea
Human point-of-care urine multidrug test or ○ Maropitant 1 mg/kg SQ q 24h
HISTORY, CHIEF COMPLAINT gas chromatography and mass spectrometry ○ Ondansetron 0.1-0.3 mg/kg IV q 8-12h
• Ingestion of prescription medication or illicit analysis on urine or plasma can be used to
drugs confirm exposure. Drug Interactions
• Acute onset of CNS and CV stimulation; Benzodiazepines can worsen clinical signs of
head bobbing and circling is common with TREATMENT agitation and disorientation but can be used
large ingestions. for seizures if needed.
Treatment Overview
PHYSICAL EXAM FINDINGS Decontaminate asymptomatic patients. After Possible Complications
• Head bobbing, circling signs occur, treatment is symptomatic and Acute kidney injury; hyperthermia; coagulopa-
• Hyperactivity or agitation supportive. Acepromazine is the mainstay of thy; hypernatremia from activated charcoal use
• Hyperthermia treatment for clinical signs of CNS stimulation
• Tachyarrhythmias, tachycardia, or reflex and often at least partially controls the signs of Recommended Monitoring
bradycardia CV stimulation. Administration of intravenous Frequent monitoring of mentation, heart rate
• Hypertension (IV) fluids is indicated for thermoregulation, and rhythm (ECG), body temperature, blood
• Mydriasis renal protection, and CV support. pressure, hydration status, acid-base status
• Hyperesthesia
• Tremors, seizures Acute General Treatment PROGNOSIS & OUTCOME
• Coma • Decontamination
○ Emesis (p. 1188): asymptomatic patients Prognosis is generally good with prompt and
Etiology and Pathophysiology with a recent exposure (typically less than aggressive treatment. Severe hyperthermia and
• Amphetamines stimulate the release of 30 minutes with prompt-release product, seizures are indicators of a worse prognosis.
catecholamines, resulting in an increase in up to 2 hours with extended-release product)
norepinephrine, dopamine, and serotonin ○ Activated charcoal 1 g/kg PO with sorbitol PEARLS & CONSIDERATIONS
and inhibiting monoamine oxidase. or other cathartic for asymptomatic
• Increased catecholamine release and inhibi- patients with recent exposure (monitor Comments
tion of reuptake results in vasoconstriction for hypernatremia) • Acepromazine is the mainstay of treatment.
with hypertension, tachycardia, and CNS • Control of CNS stimulation Failure to control stimulatory signs is often
stimulation. Cardiac output is typically not ○ Acepromazine 0.05-1 mg/kg IV, titrate to a direct result of conservative dosing of
affected due to reflex bradycardia. effect, give prn, or acepromazine.

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