Problems 6
HIGH Oclacitinib (Apoquel) intoxication
The patient has a history of Apoquel administration prior to presentation and is showing symptoms associated with toxicity. The literature indicates that oclacitinib intoxication in cats can lead to a spectrum of severe signs, and cats appear to be more sensitive to these effects than dogs.[1] Since the release of the palatable chewable formulation, severe signs have been reported following overdose in cats.[2] Clinical signs of overdose can be severe and may include gastrointestinal, cardiovascular, and central nervous system signs.[3]
HIGH Cardiovascular toxicity secondary to oclacitinib
The patient has a Grade III/VI precordial systolic murmur and mild tachycardia. Oclacitinib intoxication in cats has been associated with cardiovascular signs including tachycardia and new-onset heart murmur.[1] The new-onset murmur combined with persistent tachycardia could be suggestive of myocardial inflammation or acute cardiac stress.[3] This is consistent with the spectrum of signs reported in oclacitinib intoxication.[1]
MODERATE Sympathetic overactivity / autonomic nervous system disturbance
The patient has protruding third eyelids bilaterally, tachycardia, and appears stressed. The clinical patterns detected describe this as autonomic sympathetic overactivity suggesting systemic toxicity or catecholamine excess. Protruding third eyelids is a well-recognized sign of autonomic dysfunction, and these clinical signs are well documented in oclacitinib intoxication.[1]
HIGH Potential for acute kidney injury
While no lab data is provided, oclacitinib intoxication in cats at dosages of ~5–20 mg/kg has resulted in acute kidney injury in reported cases.[1] Cats appear to be more sensitive to these toxic effects.[2] Marked elevations in BUN and creatinine have been noted within 12–72 hours of exposure.
HIGH Potential for hepatotoxicity
Oclacitinib intoxication has been associated with hepatotoxicity resulting in elevated hepatic enzymes in reported cases.[1] While not confirmed in this patient without lab work, it is a reported problem in the spectrum of severe signs from oclacitinib intoxication.
MODERATE Risk of systemic inflammatory response
The clinical patterns detected suggest an inflammatory toxic effect. A case report on a different JAK inhibitor (ruxolitinib) toxicosis discusses an associated systemic inflammatory response and cytokine dysregulation.[4] While not specific to oclacitinib, systemic inflammation warrants consideration in the setting of JAK inhibitor toxicity.
Recommended Diagnostics 9
HIGH Complete Blood Count (CBC)
To assess for leukocytosis, cytopenia, or other hematologic abnormalities. Oclacitinib intoxication can cause marked immunosuppression and changes in blood cell counts.[1]
HIGH Serum Biochemistry Panel (BUN, Cr, ALT, AST, ALP, Cholesterol, Amylase)
To assess for acute kidney injury (marked elevations in BUN and creatinine), hepatic disease (increases in ALT and AST), and electrolyte derangements. Mild increases in ALT and AST have been noted with therapeutic use; elevated levels may indicate tissue hypoxia.[2][3]
HIGH Urinalysis
To assess renal function (urine specific gravity, proteinuria) and evaluate for signs of kidney damage secondary to oclacitinib toxicity.[1]
HIGH Blood Pressure Measurement
To assess for hypotension, a complication of oclacitinib, and evaluate for signs of shock. Patient has tachycardia and sympathetic overactivity which may indicate changes in blood pressure.
HIGH Electrocardiogram (ECG)
To characterize the tachycardia (sinus vs arrhythmia), rule out other arrhythmias, and provide a baseline for monitoring cardiovascular status. Sinus tachycardia has been documented in JAK inhibitor toxicity cases.[1][5]
HIGH Echocardiography
To investigate the cause of the new-onset precordial systolic murmur (Grade III/VI) and tachycardia in the context of drug toxicity. Critical to rule out structural heart disease (eg hypertrophic cardiomyopathy), myocardial inflammation, or stress-induced cardiomyopathy. Myocarditis is a differential for new murmur and tachycardia in a toxic patient.[4][8]
SUGGESTED Cardiac Troponin I (cTnI)
To screen for myocardial injury or myocarditis, which could be secondary to a systemic inflammatory response or direct toxic effect, explaining the new murmur and tachycardia. Elevated troponin has been associated with myocarditis in cats.[8]
SUGGESTED Coagulation Profile (PT/PTT or viscoelastic testing)
Hepatotoxicity from oclacitinib can result in altered coagulation. Serial assessment is important for proactive management.
HIGH Serial monitoring of BUN, Creatinine, and Urine Output
Acute kidney injury can develop within 12–72 hours of exposure; serial monitoring allows early detection of complications.
Treatment Considerations 14
Immediate Decontamination (if within appropriate timeframe)
Consider prompt decontamination with emesis induction and/or a single dose of activated charcoal (~1 g/kg PO) if the ingestion is recent and the patient is asymptomatic for aspiration risk.[2][3]
HIGH Intravenous Fluid Therapy
Begin IV fluid therapy for supportive care and to protect renal function. Dosages of 15–25 mg/kg of oclacitinib have resulted in acute kidney injury in cats.[1] Fluid rates should be tailored to resuscitation requirements, hydration status, and perfusion parameters, with frequent reassessment.[2][3]
Cardiovascular Monitoring and Management
Continuously monitor ECG for arrhythmias. Tachycardia is a concerning cardiovascular sign of oclacitinib intoxication.[1] Sedatives can be considered as first-line therapy to reduce sympathetic tone and improve cardiovascular function.[2]
Administer Sedation for Tachycardia/Anxiety
For persistent tachycardia/anxiety, consider butorphanol. Formulary: Butorphanol 0.2–0.4 mg/kg IV, IM, SC q4–6h.[9]
Consider Beta-Blocker for Refractory Sinus Tachycardia
If tachycardia is severe or refractory to sedation, consider a beta-blocker like atenolol for rate control in cats. Formulary: Atenolol 6.25–12.5 mg/cat PO q12–24h. Careful dosing with attention to bradycardia and hypotension.[1]
Gastrointestinal Support and Monitoring
Manage GI signs like vomiting, which are common in overdose.[1] Maropitant can be administered at 1 mg/kg SC, PO or IV q24h as an antiemetic. Consider GI protectants like omeprazole at 0.5–1 mg/kg PO q24h.[5][7]
Hepatoprotective Support
Initiate hepatoprotective therapy due to risk of hepatotoxicity and elevated ALT.[1] Administer S-adenosyl-L-methionine (SAMe)/silybin. Formulary: SAMe/silybin 10 mg/kg PO q24h.[3][6]
Serial Laboratory Monitoring
Monitor serial lab work including CBC, serum biochemistry (with focus on BUN, creatinine, ALT, cholesterol) and urinalysis. Marked elevations in BUN and creatinine can occur within 12–72 hours of exposure.[1] Check for resolution and monitor response.[3]
Ocular Support
Monitor for and support ocular signs such as elevated nictitans (third eyelid).[1] In cases of JAK inhibitor toxicosis with ocular involvement, ophthalmic lubrication may be indicated.[2]
Withhold Oclacitinib
Immediately discontinue any further administration of oclacitinib.[1]
Report the Intoxication
Contact an Animal Poison Control Center (APCC) to increase the knowledge base. Report the information to the manufacturer and the FDA.[1][2]
Monitor for Bradycardia
Be aware that the clinical course may progress from tachycardia to bradycardia, consistent with an exaggerated cytokine-induced response.[3]
Assess for Myocardial Injury
Consider checking cardiac troponin I if myocarditis or acute cardiac stress is suspected based on the new murmur and tachycardia.[8]
Avoid Inappropriate Cardiac Medications
Pimobendan and other positive inotropic/chronotropic agents are not recommended for cats with hypertrophic cardiomyopathy (HCM) unless specific indications are present (eg CHF).[10] The use of pimobendan in cats with obstructive cardiomyopathy carries a low risk of adverse hemodynamic effects.[9]
VETINUITY