Sulfonamide Hypersensitivity in Dobermans
A lesser-known health concern is Sulfonamide (Antimicrobial) Hypersensitivity, sometimes referred to as Sulfonamide Toxicity in Dobermans.
The Issue of Sulfonamide (Antimicrobial) Hypersensitivity (Sulfa-containing Drugs, e.g., Bactrim)
A lesser-known but significant concern for Doberman owners is the hypersensitivity to sulfonamide antimicrobials, such as drugs containing sulfamethoxazole and sulfadiazine. Since the drug can have an effect that takes place after a few days (one study found that symptoms develop in an observed range of 5–36 days, with an average of 12 days), some people also refer to the issue as toxicity. While we provide a list* of medications containing sulfonamides in the ‘further resources’ section, let’s focus on the example of the antibiotic Bactrim, often prescribed in veterinary practice within the sulfa-containing drugs.
While Bactrim (a combination of sulfamethoxazole and trimethoprim) is commonly used to treat a variety of bacterial infections (e.g., Urinary Tract Infections) in many dog breeds, Dobermans can have a unique and severe reaction to this medication.
The reason behind this adverse reaction lies in the breed's genetic makeup. Dobermans may have a higher sensitivity to the components of Bactrim, especially the sulfamethoxazole component, leading to potentially life-threatening side effects such as severe immune-mediated reactions, skin rashes, liver damage, and low blood cell counts. The exact mechanism is not entirely understood, but it is believed to be related to the breed's genetic predisposition to immune system issues. One of the genes involved is the CYB5R3 729GG variant, but more gene variants are more than likely involved in this hypersensitivity issue.
The symptoms of Bactrim hypersensitivity in Dobermans can vary but often include fever, lethargy, jaundice, bloody urine, or skin lesions. If a Doberman is being treated with a medication that contains sulfonamide antimicrobials, such as Bactrim, and starts exhibiting any adverse reactions, it is crucial to stop the medication and seek veterinary care immediately.
Why It's an Issue
The main issue with sulfonamide antimicrobial hypersensitivity in Dobermans is that it's not widely recognized by all pet owners or even some veterinarians. Awareness is key, as early detection and the possible avoidance of this antibiotic can significantly reduce Dobermans' risk of severe reactions. Alternatives to Bactrim are available, and a veterinarian can prescribe a different medication that is safe for Dobermans if an antibiotic is needed.
However, while there is a concern, Bactrim toxicity may not affect all Dobermans. Thus, weighing the risks and benefits of any medication, including Bactrim or other medications containing sulfonamide antimicrobials, is essential. As a responsible dog owner, speak to your veterinarian before making any decisions regarding your dog’s medications.
Moreover, sulfonamide-containing drug prescriptions may have decreased, but antimicrobial resistance to “safer” antibiotics (e.g., beta-lactams, fluoroquinolones) has increased. As such, veterinarians may feel inclined to prescribe sulfonamide-containing drugs more often than in the recent past. Again, talk to your veterinarian to discuss any of your concerns.
Further Resources
Owner Reported Symptoms + List* of Brand Names:
NSAIDS/Sulfa Drugs/Deramaxx and Dobermans:
https://dpca.org/wp-content/uploads/018-nsaids.pdf
Warning-Adverse Reactions To Sulfa Drugs:
https://dpca.org/breeded/warning-adverse-reactions-to-sulfa-drugs/
Scientific Literature:
Sulfadiazine-induced allergy in six Doberman pinschers:
https://pubmed.ncbi.nlm.nih.gov/3972708/
Evaluation of Polymorphisms in the Sulfonamide Detoxification Genes CYB5A and CYB5R3 in Dogs with Sulfonamide Hypersensitivity:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4474156/
A single nucleotide polymorphism in the canine cytochrome b5 reductase (CYB5R3) gene is associated with sulfonamide hypersensitivity and is overrepresented in Doberman Pinschers:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5932251/
* We do not guarantee that the list provides all medications containing sulfa components. Please speak to your veterinarian about any concerns you may have regarding this or other issues.
