- 6 days ago
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Why Compounded Veterinary Medications Fall Short - Stability, Safety & Potency Risks in 2026
An Evidence-Based Review of Risks, Limitations, and Opportunities
By Dr. Sarah Wade, Business Development & Alliance Manager
This article was originally written for the 2026 Animal Health, Nutrition, and Technology Innovation Summit (AHNTI), where Eirgen Pharma was invited to contribute expert insights on a topic of their choice. We are pleased to share an expanded version for our broader veterinary, pharmaceutical, and scientific audience.
Veterinary compounding plays an important role when no suitable approved treatment exists, allowing clinicians to adjust dosage strength, alter formulations, or remove harmful excipients. However, unlike FDA-approved veterinary medicines, compounded preparations lack validated potency, stability, and quality assurance. As a result, they frequently demonstrate inconsistent therapeutic performance - particularly in high-risk areas such as oncology, antifungal therapy, endocrinology, and immunosuppression.
Every variability in a compounded product becomes a variability in a therapeutic outcome.
Medication management in veterinary practice is uniquely challenging. Patients range in size from a few grams to several hundred kilograms, and compliance often depends on ease of administration and palatability. While compounding has historically been used to bridge gaps when approved products are unavailable or unsuitable, it carries significant risks that can compromise patient health. At the same time, pharmaceutical manufacturers have an opportunity to better serve veterinarians and pet owners by creating formulations designed with usability in mind.
Clinicians may consider compounded medications when;
No FDA-approved product exists in the required form or strength
An ingredient in an approved product is unsafe for a particular species
The animal cannot tolerate the approved dosage form
An approved product is temporarily unavailable due to a shortage or discontinuation
It is important to note that cost alone is not considered an appropriate justification
for prescribing a compounded product when an FDA-approved option is available.
While compounding can address short-term gaps, it differs fundamentally from commercial manufacturing. FDA-approved veterinary medicines must demonstrate validated potency, stability, bioavailability, and safety in target species. Compounded products are not held to these same evidentiary standards.
Where Compounding Introduces Clinical Risk
Although compounding can provide short-term solutions, it is important to recognize its limitations;
Variable Efficacy & Bioavailability
Changes in dosage form (e.g., tablet → suspension or transdermal gel) can dramatically alter absorption. Compounded formulations typically lack controlled pharmacokinetic evaluation, making clinical outcomes unpredictable.
Stability
Compounded medications rarely undergo validated stability testing. Without proper data, expiration dates and potency retention are assumptions rather than guarantees. For treatments requiring tight dose control — such as trilostane, lomustine, and cyclosporine — this lack of stability presents significant therapeutic risk.
Inconsistent Quality
Compounding pharmacies are not required to follow cGMP standards. Potency may fluctuate between batches, and formulations can change without clinician's notification.
Safety
Without FDA review, safety in target species is not validated. Bulk APIs may vary in purity, and adverse events often go unreported.
Cross Therapeutic Case Studies
Case Studies | Result |
Oncology - Lomustine & Chlorabucil | Highly inconsistent potency (58% - 109%+ variation), subtherapeutic dosing, treatment failure. |
Antifungal - Itraconazole | Markedly reduced bioavailability in compounded forms. |
Endocrinology - Trilostane | Only 40.9% of compounded samples met strength requirements |
Dermatology/Immunology - Cyclosporine | Significant inaccuracies causing either therapeutic failure or toxicity |
What Does This Mean for Practitioners and Manufacturers?
For clinicians, inconsistent compounded medications introduce uncertainty into clinical decision-making and can erode client trust when outcomes fall short of expectations. For manufacturers, continued reliance on compounding signals an unmet need in the marketplace rather than an optional solution.
A Call For Better Commercial Formulations
The persistent reliance on compounding reflects a gap in the marketplace rather than an ideal solution.
Pharmaceutical manufacturers can better support veterinary medicine by;
Expanding dose strengths to accommodate diverse patient sizes
Developing palatable, user-friendly dosage forms to improve compliance
Ensuring rigorous potency, stability, and safety testing under FDA oversight
Addressing underserved therapeutic areas with approved alternatives
By investing in formulation science with the end-user in mind, pharmaceutical companies can reduce the reliance on compounding and ensure that patients receive therapies with consistent, predictable results.
Veterinary healthcare continues to advance rapidly, with increased focus on species‑specific formulations, high‑potency therapies, and improved bioavailability across dermatology, oncology, endocrinology, and infectious disease. As these therapeutic areas grow, clinicians and manufacturers alike are placing greater emphasis on predictable pharmacokinetics, validated stability, and quality‑driven manufacturing processes — essentials for delivering consistent patient outcomes.
Compounded medications still play an important role in cases where no approved alternative exists. However, reviewing the available scientific data enables industry leaders to identify where strategic formulation development, improved stability profiling, and modern manufacturing technologies can further strengthen therapeutic reliability. This evidence‑based approach supports veterinarians while accelerating progress across the broader animal health ecosystem.
The continued use of compounded preparations demonstrates the need for more purpose‑built veterinary formulations that are accessible, stable, palatable, and designed with real‑world clinical workflows in mind. By expanding dose ranges, diversifying dosage forms, and investing in advanced manufacturing capabilities, pharmaceutical developers can meaningfully enhance treatment consistency and clinician confidence.
Rather than highlighting limitations, this represents an exciting frontier for innovation — one where manufacturers, veterinarians, and regulatory partners can collectively advance safer, more effective, and more predictable veterinary therapies.
Learn More About Eirgen Pharma Manufacturing
At Eirgen Pharma, we are committed to shaping the future of high-quality veterinary medicine. If you are exploring new formulation strategies, seeking alternatives to compounded products, or looking to collaborate on complex veterinary manufacturing & development, our team can help turn insight into innovation.
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