Common Methods of Administering Analgesics and Antibiotics to Research Animals

In the field of laboratory animal science, the proper administration of analgesics and antibiotics to laboratory animals is essential for both ethical treatment and the integrity of experimental results. Our 2024 Medication Delivery in Laboratory Animal Science Survey sheds light on the different medications commonly administered to laboratory animals as well as the methods animal care teams are using to deliver them. Let’s delve into each method and its benefits, as well as the challenges researchers may encounter.


Method Overview: Injection-based administration involves delivering analgesics or antibiotics directly into the body of the research animal through subcutaneous, intraperitoneal, or intravenous routes. This method ensures rapid and precise delivery of medications, making it ideal for acute pain management or systemic antibiotic treatment. According to the survey results, injection is the most common delivery method for both analgesics and antibiotics, with 90.4% of participants delivering analgesics via injection and 57.6% delivering antibiotics with injections.

Benefits of injections:

  • Precision: Allows for accurate dosage control and immediate drug absorption.
  • Efficiency: Ensures direct delivery to the bloodstream or target tissues, maximizing therapeutic efficacy.
  • Flexibility: Suitable for a wide range of analgesics and antibiotics, including aqueous solutions, suspensions, or oil-based formulations.

Challenges with injections:

  • Technical Skill: Injection procedures require training and expertise to perform safely and accurately, posing a challenge for inexperienced personnel.
  • Stress: Some animals may exhibit stress or discomfort during injections, affecting their behavior and research outcomes.
  • Risk of Complications: Incorrect injection techniques or site selection can lead to tissue damage, infection, or adverse reactions.

Water-Based Delivery

Method Overview: Water-based delivery involves incorporating analgesics or antibiotics into the drinking water provided to research animals. This method offers a convenient and non-invasive way to administer medications to large groups of animals, ensuring consistent dosing over an extended period. According to the survey results, water-based delivery is more common with antibiotics than it is with analgesics. Out of the survey participants that deliver antibiotics, 66.3% cited water delivery as a commonly used method.

Benefits of water-based delivery:

  • Ease of Administration: Simply mix medications into the drinking water, eliminating the need for individual dosing.
  • Continuous Exposure: Provides continuous access to medication, ensuring consistent therapeutic levels in the body.
  • Minimized Stress: Reduces stress associated with handling or injections, promoting animal welfare in group-housing settings.

Challenges with water-based delivery:

  • Palatability: Some medications may impart a bitter taste to the water, leading to decreased consumption and variable dosing.
  • Water Intake Variability: Individual differences in water consumption among animals can result in uneven medication intake, affecting treatment efficacy.
  • Environmental Factors: Contaminants or changes in water quality may impact medication stability and effectiveness.

Feed Incorporation

Method Overview: Feed incorporation entails blending analgesics or antibiotics into the animal’s diet. This method ensures medication intake during regular feeding intervals, making it suitable for long-term treatment regimens or antibiotic prophylaxis.

Benefits of feed incorporation:

  • Seamless Integration: Medications are mixed directly into the feed, ensuring uniform distribution and palatability.
  • Long-Term Compliance: Animals receive medication during regular feeding, reducing the risk of missed doses or non-compliance.
  • Minimal Handling: Minimizes stress and handling-related variables, enhancing animal welfare in research colonies.

Challenges with feed incorporation:

  • Feed Palatability: Medication additives may alter the taste or texture of the feed, leading to decreased consumption and potential nutrient imbalances.
  • Dosage Accuracy: Ensuring uniform distribution of medications throughout the feed can be challenging, resulting in variability in dosage delivery.
  • Selective Feeding: Some animals may selectively consume certain feed components, leading to uneven medication intake among individuals.

Gel Formulations

Method Overview: Gel formulations offer a novel approach to medication delivery, providing a palatable and easily consumed medium for analgesics or antibiotics. These formulations can be particularly useful for animals that may resist other methods of administration.

Benefits of gel formulations:

  • Palatability: Flavored gel formulations, such as MediGel® Sucralose, DietGel® Boost, and LabGel® Banana, enhance acceptance and consumption by research animals, ensuring consistent medication intake.
  • Ease of Consumption: Soft gel textures are easily ingested, making them suitable for animals of all sizes and species.
  • Versatility: Gel formulations can accommodate various medications, offering flexibility in treatment options.

Challenges with gel formulations:

  • Dosage Control: Ensuring accurate dosage delivery can be challenging, especially with animals that may consume varying amounts of the gel.
  • Storage Stability: Gel formulations with medications mixed in may require specific storage conditions to maintain stability and efficacy.
  • Individual Variation: Some animals may exhibit aversion to gel textures or flavors, leading to inconsistent medication intake and efficacy. We recommend requesting a free sample to verify palatability for your animals.

Incorporating gel formulations into medication protocols provides researchers with an effective and convenient means of ensuring medication compliance and animal welfare. However, each method presents its own set of challenges that researchers must consider when designing experimental protocols. By understanding these challenges and implementing appropriate mitigation strategies, researchers can optimize medication delivery and enhance the validity of their research outcomes.


Each method of administering analgesics and antibiotics presents unique advantages tailored to diverse research needs. By understanding the benefits and considerations of injection, water-based delivery, feed incorporation, and gel formulations, researchers can make informed decisions to ensure the welfare and well-being of laboratory animals while maintaining the integrity of scientific studies. Leveraging innovative solutions like gel formulations can enhance medication compliance and contribute to the advancement of scientific knowledge in animal research.


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