Dr. C and the Case of the Medication Mix-Up

 

A nineteen-month-old intact male Goldendoodle weighing 15 pounds was presented to Dr. C for vomiting and diarrhea of 72 hours duration with increasing diarrhea frequency and diminishing vomiting. The patient had recently been boarded for the first time and was noted to have eaten well during his stay. On physical exam the patient was found to be mentally quiet and alert and have normal temperature, pulse and respiration with increased borborygmi and fluid noted in the gastrointestinal tract upon abdominal palpation. The owner reported no known history of dietary indiscretion or suspect foreign body. A fecal float was negative for parasite ova. The patient was found to have clostridial overgrowth on direct fecal smear. Complete blood count and chemistry screen were offered and declined.

The patient was prescribed Metronidazole at a dose of 500 mg by mouth twice daily for 7 days. The patient was discharged to the owner’s care. Later in the day, Dr. C recognized that the correct dose of Metronidazole for the patient’s body weight was 100 mg twice daily (dose for clostridium enteritis is 10-15 mg/kg by mouth twice daily). Dr. C proceeded to call poison control for guidance on Metronidazole toxicity. The owner was contacted and reported having administered a single dose at the incorrect dosage. The owner was advised to immediately return with the patient. Upon arrival, the patient was given Apomorphine to induce vomiting. The patient vomited a small amount of food with no metronidazole tablet evident. The patient was then administered activated charcoal via nasogastric tube and Cerenia subcutaneously 1 hour after the apomorphine. The patient was discharged after 3 hours when no neurological abnormalities were observed. The owner presented the patient to an emergency clinic later that evening for a possible seizure. The patient was treated by the second veterinarian with intravenous fluids and Diazepam. The patient was discharged the next morning and no further care was required. 

The client requested compensation from Dr. C for the fees incurred at the emergency clinic. Dr. C notified the insurance carrier of the medication error and the actions taken. Medical records from both Dr. C and the second veterinarian were provided and the symptoms and follow-up treatment were found to be consistent with a medication error. Dr. C’s insurance carrier paid $2800 for the follow-up care delivered at the emergency clinic.


Understanding the Case

Metronidazole is an antibiotic drug commonly used in the management of vomiting and diarrhea and may be an effective treatment for clostridial enteritis (including c. difficile and c. perfringens). It is also used in the treatment of antibiotic-responsive diarrhea after ruling out other causes. Known potential side effects of Metronidazole include inappetence, vomiting, and diarrhea. This medication can also cause neurologic effects such as tremors and seizures. Neurologic side effects are more likely after prolonged use or overdosing.

Dr. C made the best choice by contacting the owner and poison control centers to provide care in the best interest of the patient after identifying a known error. Additionally, Dr. C provided follow up instructions to the owner so that the owner understood what abnormalities to be monitoring for and where to seek care after hours. This led to an excellent patient outcome.

 

References:

JA, L. Metronidazole Risks, Clinicians Brief. 2014(September)

Marks, SL, Rankin, SC,, Byrne, BA., Weese, JS., Enteropathogenic bacteria in dogs and cats: diagnosis, epidemiology, treatment and control. J Vet Intern Med. 2011;25(6);1199-1208.