The following blog post describes duloxetine toxicity in dogs. Please read below for information on what duloxetine is, how it affects dogs, and what to do if a client calls your clinic after their pet ingests this medication.
It is common to find antidepressants and other psychiatric medications in the average American home and it is vital that we educate our clients and pet parents on the importance of keeping their medications out of reach of their pets. One example of a commonly used medication to treat depression and anxiety, as well as pain from diabetic neuropathy, fibromyalgia, and stress urinary incontinence in people is duloxetine.
Duloxetine is a selective serotonin and norepinephrine reuptake inhibitor (SSRI) with trade names such as Cymbalta®, Tentreve®, Irenka®, Drizalma® sprinkles, as well as generic versions. Duloxetine poisoning is most commonly seen in dogs due to their curious nature. Clinical signs are generally consistent with serotonin syndrome. Duloxetine is well absorbed after oral ingestion and reaches peak plasma concentration in dogs approximately 2 hours after ingestion. Pearls within the capsule are individually coated which delays absorption by approximately 30 minutes following ingestion. Clinical signs may be seen within 30 minutes up to two hours following ingestion. Asymptomatic animals should be monitored for 4 hours following ingestion as a precaution. Metabolism primarily occurs in the liver and elimination is predominantly through urine as well as some fecal elimination.
Clinical signs can be broken down into three categories — neurologic, gastrointestinal, and autonomic nervous system. Neurologic signs include vocalization, lethargy, agitation, dilated pupils, trembling, ataxia, and even seizures with large ingestions. Typical gastrointestinal signs include vomiting and diarrhea. Autonomic nervous system signs include hyperthermia, cardiac arrhythmias, hypertension, and tachypnea. Chronic exposure to duloxetine in dogs can lead to increased liver enzymes (ALT, AST) however, no overt hepatic injury or cholestasis has been reported.
Diagnosis of duloxetine ingestion is based on history of ingestion and clinical signs. Recommendations are based on the dose ingested and clinical signs present, if any. For dogs that do exhibit duloxetine poisoning, treatment is supportive and symptomatic. Specific therapies may include intravenous fluids, sedation with acepromazine or chlorpromazine , methocarbamol for tremors, antiemetics, cooling measures, hepatoprotectants, and intravenous lipid emulsion in cases with severely affected patients..
The skilled veterinarians and veterinary specialists at Pet Poison Helpline® are available 24 hours a day, seven days a week to assist with determining the degree of concern after a duloxetine ingestion and to offer guidance regarding appropriate therapy.
Prognosis for recovery is generally good to excellent with treatment. Unfortunately, there is limited information on duloxetine poisoning in cats. Therefore, the above decontamination and treatment suggestions are often recommend for the feline patient as well.
Written by:
Hannah Timpe, DVM student extern, University of Minnesota Class of 2022
Heather Handley, DVM, Senior Consulting Veterinarian, Clinical Toxicology
