June 2025
In this VETgirl online veterinary continuing education blog, Dr. Justine Lee, DACVECC, DABT talks about (crystal) methamphetamine toxicity in dogs… and why it’s so important that you be able to recognize the clinical signs and treatment!

Ice, Ice, Baby: Crystal Methamphetamine Toxicity in a Dog

By Dr. Justine Lee, DACVECC, DABT
Director of Medicine / CEO, VETgirl

Presenting Complaint

This patient presented to the emergency room for acute presentation – yet history of several recurrent episodes in the previous year – of agitation, hyperactivity, and muscle tremors. The owner described these as “seizure-like activity.” These episodes had occurred six times over the past year, each resolving within 24 to 36 hours.​ Based on the patient displaying several episodes over the previous year, a more chronic (versus subacute or acute) neurologic condition was initially considered.

 

Amphetamines

In human medicine, amphetamines are used for a variety of medical and illicit reasons. Legal forms include prescription medications for attention-deficit disorder/attention deficit-hyperactivity disorder (ADD/ADHD), weight loss, and narcolepsy. Examples of amphetamines include:

  • Dextroamphetamine
  • Amphetamine (Adderall®)
  • D-amphetamine (Dexedrine®)
  • Methamphetamine (Desoxyn®)
  • Lisdexamfetamine (Vyvanse®)

Illegal forms of amphetamines include street drugs like methamphetamine, crystal meth, and ecstasy.

This class of drugs acts as sympathomimetic agents, meaning they stimulate the sympathetic nervous system. Amphetamines also cause stimulation of α- and β-adrenergic receptors and stimulate release of serotonin and norepinephrine; this results in increased levels of catecholamines in the synaptic cleft and stimulation of the postsynaptic receptors. Amphetamines also lower the reuptake and breakdown of monoamines, such as the catecholamine, serotonin, which may cause some patients to develop serotonin syndrome. The oral median lethal dose for amphetamines in dogs varies but has been reported between 9–27 mg/kg. Rapid recognition and intervention are crucial to prevent severe complications or death.

 

Treatment and Management

So, what’s the approach to treatment of amphetamine toxicosis? In general, if the patient is already symptomatic after ingestion of methamphetamine or amphetamines, it is too late to decontaminate the patient (e.g., in other words, no emesis induction or activated charcoal administration!). (In some circumstances with extended-release (ER) formulation amphetamines, one dose of activated charcoal can be administered once the patient has been stabilized). Depending on the severity of clinical signs and financial limitations of the pet owner, ideal treatment includes overnight hospitalization for treatment and management until clinical signs resolve.  Medical management includes the following:

1. Fluid therapy

Fluid therapy is warranted with amphetamine toxicosis to help maintain hydration, treat/flush myoglobinuria (resulting from rhabdomyolysis which can occur with excessive muscle stimulation and hyperthermia), and aid in urinary elimination of the toxin. Provided cardiopulmonary disease is not present, the use of aggressive intravenous (IV) fluid therapy at approximately 2X maintenance is warranted. Patients should be monitored appropriately and fluid therapy adjusted appropriately based on clinical signs, evidence of hemodilution (e.g., in general, aiming for a PCV/TS of 35%/5 in a normal healthy patient at sea level), weight monitoring, etc.

2. Cooling measures

With severe hyperthermia secondary to tremors, active cooling may (rarely) be necessary if temperatures exceed 105F (40.5C). This VETgirl doesn’t typically actively cool these patients (e.g., with cold water baths), but rather relies on the cooling effect of room-temperature IV fluid therapy, combined with muscle relaxants (e.g., intravenous methocarbamol and acepromazine) to stop the tremors contributing to the hyperthermia (see below).

3. Sedation

In the tachycardiac, hypertensive amphetamine patient, the use of repeated doses of low dose acepromazine is warranted (e.g., 0.01-0.05 mg/kg, IV, repeat as necessary). With severe cases, doses as high as 0.1 mg/kg, IV, may be warranted. In general, this VETgirl avoids exceeding 3 mg TOTAL dose per dog due to severity of hypotension and sedation.

4. Muscle Relaxants

Methocarbamol is a safe, centrally-acting muscle relaxant that can be used to alleviate muscle tremors and rigidity.​ This VETgirl starts at 50 mg/kg administered as a slow IV bolus, and repeated as needed in the emergent patient, knowing that some patients can be severe and may require a constant rate infusion (CRI) of methocarbamol. While the labeled dose states not to exceed 300 mg/kg/day of methocarbamol, (SIDE NOTE: this recommendation is meant to lower the risk of developing propylene glycol toxicity from the carrier agent in injectable methocarbamol)  this VETgirl has personally done this in patients without incident.

5. Serotonin Antagonism:

Cyproheptadine is a serotonin antagonist and can be used to counteract serotonin syndrome, a potential condition that can arise from excessive serotonin activity from amphetamines. It helps to mitigate symptoms such as agitation and hyperthermia. Unfortunately, since it is typically only available in oral form, I generally limit its use for outpatient therapy or as a medication to go home with the patient.

6. Anticonvulsant Therapy:

With amphetamine toxicosis, severe, acute seizures can initially be seen with exposure. In general, pick whatever anticonvulsant you have in your clinic to control seizures and severe agitation. In VETgirl’s opinion, intravenous phenobarbital is preferred over benzodiazepines as it has a longer duration of action and is more efficacious in controlling hyperexcitability; rarely, some dogs can be worse with benzodiazepine treatment and get more dysphoric.

7. Supportive Care:

Additional symptomatic supportive care for treatment of amphetamine toxicosis includes blood pressure and ECG monitoring, anti-arrhythmic therapy, thermoregulation, and anti-emetic therapy (if vomiting).

Client Communication During Suspected Toxicity Cases

When toxicity is suspected in the veterinary patient, obtaining an accurate history is vital yet challenging, especially if illicit substances are involved. Strategies to facilitate open communication include:​

  • Non-Judgmental Approach: Emphasize that the primary concern is the pet’s health, not the owner’s personal choices.​ I often use language like “Any chance your [dog] got into anything like grapes, raisins, over-the-counter medication, household cleaners, antifreeze, pot, illicit drugs, or anything?”
  • Confidentiality Assurance: Reassure clients that information shared is confidential and solely for the purpose of medical care.​ I often use language like “You’re not going to get in trouble – I just need to figure out what’s going on so we can treat it right away.”
  • Clear Communication: Explain how specific information directly impacts diagnostic and treatment decisions, potentially affecting outcomes and costs.​ I often use language like “Work up for a dog showing signs [like this] often include really expensive tests like anesthesia and MRI or CT, and before we do that, I just want to make sure it’s not any kind of poisoning, which would be less expensive to treat.”

In this case, initial denial of potential toxin exposure was overcome by building rapport and trust, leading to the revelation of the dog’s access to environments where methamphetamine was present.

Conclusion

Within 24 hours of initiating treatment, the dog’s clinical signs improved dramatically, and the owner was made aware to keep the dog away from the other parent’s house to minimize illicit drug exposure. Thankfully, the outcome was good and the patient recovered well!

This case underscores the importance of considering toxin exposure in dogs presenting with acute neurologic and cardiovascular signs. Timely diagnosis, appropriate therapeutic interventions, and effective communication with pet owners are essential components in managing such emergencies.​

Note: For immediate assistance with potential toxin exposures, veterinarians can contact the ASPCA Animal Poison Control Center at (888) 426-4435, available 24/7 for life-saving advice and recommendations.


  3. Emily Golemboski says:

    I’ve seen an amphetamine GSP. I hope I don’t get another one but this is very helpful.

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