PETS ARE PATIENTS TOO: A REVIEW OF VETERINARY COMPOUNDING
Liz Fredrickson, PharmD, BCPS
Liz Fredrickson is an Associate Professor of Pharmacy Practice and Pharmaceutical Sciences at the Northeast Ohio Medical University College of Pharmacy. She serves as Director of Instructional Labs and is course director for the Basic Pharmaceutics Lab, Parenteral Products, and Parenteral Products Lab courses.
Among all healthcare providers, pharmacists are the only ones able to care for human and animal patients. Despite a large need, there is currently limited availability of approved drug products for veterinary species. The provision of compounded medications fills a gap in the lack of manufactured drug products and therefore plays a critical role in the health and well-being of animals. Providing veterinary compounding services comes with the important responsibility for pharmacists and pharmacy technicians to not only be well- trained in pharmaceutical compounding but also knowledgeable of key pharmacokinetic, physiologic, and formulation considerations when compounding for various animal species. This course will provide a review of the benefits and risks associated with veterinary compounding, pertinent rules and regulations, common veterinary dosage forms, and considerations when preparing veterinary compounds.
RxCe.com LLC is accredited by the Accreditation Council for Pharmacy Education (ACPE) as a provider of continuing pharmacy education.
Universal Activity Number (UAN): The ACPE Universal Activity Number assigned to this activity is
Pharmacy Technician 0669-0000-23-057-H07-T
Credits: 1 hour of continuing education credit
Type of Activity: Knowledge
Media: Internet/Home study Fee Information: $4.99
Estimated time to complete activity: 1 hour, including Course Test and course evaluation
Release Date: April 15, 2023 Expiration Date: April 15, 2026
Target Audience: This educational activity is for pharmacists.
How to Earn Credit: From April 15, 2023, through April 15, 2026, participants must:
Read the “learning objectives” and “author and planning team disclosures;”
Study the section entitled “educational activity;” and
Complete the Course Test and Evaluation form. The Course Test will be graded automatically. Following successful completion of the Course Test with a score of 70% or higher, a statement of participation will be made available immediately. (No partial credit will be given.)
Credit for this course will be uploaded to CPE Monitor®.
Learning Objectives: Upon completion of this educational activity, participants should be able to:
Identify benefits of compounding for veterinary patients
Recall regulatory and legal considerations when compounding for veterinary patients
Describe dosage forms that may be compounded for veterinary patients
Describe important pharmacokinetic, physiologic, and formulation considerations when compounding for veterinary patients
The following individuals were involved in the development of this activity: Liz Fredrickson, PharmD, BCPS, and Pamela Sardo, PharmD, B.S. Pamela Sardo was an employee of Rhythm Pharmaceuticals until March 2022 and has no conflicts of interest or relationships regarding the subject matter discussed. There are no financial relationships relevant to this activity to report or disclose by any of the individuals involved in the development of this activity.
© RxCe.com LLC 2022: All rights reserved. No reproduction of all or part of any content herein is allowed without the prior, written permission of RxCe.com LLC.
Pharmacists may care for human or animal patients. When it comes to animal patients, there are benefits associated with veterinary compounding, pertinent rules and regulations, common veterinary dosage forms, and other considerations when preparing veterinary compounds. Pharmacists and pharmacy technicians should be familiar with the circumstances under which compounding is deemed appropriate. Pharmacists who compound medications for veterinary patients need to be familiar with the pharmacokinetic properties of animals, which can differ vastly among and between species and lead to differences in the bioavailability of drugs and their rate of elimination.
Veterinary Compounding: An Overview, Benefits, and Risks
Among all healthcare providers, pharmacists are the only ones able to care for human and animal patients.1 Despite being well-trained in pharmacotherapy, pharmaceutical compounding, and drug delivery, the majority of graduating student pharmacists receive little to no education on these topics as they pertain to animals.2 This is significant because pharmacists are becoming increasingly involved in animal care within the United States (US).2,3 Their roles include the provision of compounded medications to meet the unique and individual needs of veterinary patients.4 Depending on the pharmacy setting, pharmacists may have opportunities to compound medications for a number of different animal species, including companion pets (such as cats, dogs, and ferrets), pocket pets (small animals such as hamsters and gerbils), work animals (horses and oxen), and even zoo and exotic animals.4 The term “patient” refers to the animal or pet, while “client” refers to the pet owner.
Currently, there is limited availability of approved drug products for veterinary species, despite the large need for veterinary medications.5 The provision of compounded medications fills a gap in the lack of manufactured drug products and therefore plays a critical role in the health and well-being of animals.5 The American Veterinary Medical Association (AVMA) has recognized the importance of compounding in their statement: “Compounding
is a needed tool and provides much-needed therapeutic flexibility for veterinarians, especially considering the wide range of species and breeds veterinarians treat.”6
In 2015, the Food and Drug Administration (FDA) estimated 75,000 pharmacies compounded a total of 6,350,000 prescriptions for animals in the US.7 The FDA defines animal drug compounding as the process of combining, mixing, or altering ingredients to create a medication tailored to the needs of an individual animal or small group of animals.8 Compounding does not include the mixing, reconstituting, or other such acts that are performed in accordance with directions contained in approved labeling provided by the manufacturer directions consistent with that labeling.8
Pharmacists and pharmacy technicians should be familiar with the circumstances under which compounding is deemed appropriate. These include times when manufactured medications have been recalled or are under a drug shortage; when a patient is allergic or does not tolerate specific ingredients within a manufactured medication; when a patient requires a different strength or dosage form of medication; or when flavoring or sweetening agents need to be added to a medication to make it more palatable.8,9 Additional reasons to compound for veterinary patients are listed in Table 1.
Table 1. Reasons to Compound for Veterinary Patients9,10
|When there is a need for rapid changes in the management and disease problems in veterinary medicine
|When there is a need to achieve an appropriate treatment regimen for species, age, or size of the animal patient
|When problems associated with the treatment of a large number of animals with several drugs in a short period of time arise
|When there is a desire to achieve an additive therapeutic effect when administering two or more products at the same time
|When there is a need to combat multiple and concurrent disease processes
|When there is a need to minimize suffering, harmful stress, and mortality in animals
Conversely, there are a number of reasons for which it is inappropriate to compound for veterinary patients. One of the most important is a lack of a veterinary client-patient relationship (VCPR).11 A VCPR is a relationship in which the veterinarian is intimately familiar with the animal patient and is thereby able to diagnose and treat their medical conditions, and the client asks questions of the veterinarian and follows instructions.11 Other reasons include the availability of an FDA-approved product; compounding for use in food animals; mass manufacturing; compounding from bulk active pharmaceutical ingredients when approved products exist; to decrease cost; and to make a copy of a commercially available drug.9,11 Finally, it is important for pharmacists to establish well-working relationships with prescribing veterinarians prior to engaging in veterinary compounding. In this way, the pharmacist and veterinarian can work together to determine the best course of action regarding medication therapies for animal patients.9
Compounding Benefits for Veterinary Patients
Compounded medications have the potential to benefit veterinary patients in many of the same ways they benefit human patients. Some of the most common benefits are described below.5
Provision of unavailable medications
If no FDA-approved drug product exists for a specific species, or if these products have been recalled or are under a drug shortage, compounding pharmacists may compound these medications for veterinary patients.5 This can benefit veterinary patients and their owners, and in some cases, it can be life-saving for the pet.
Provision of a needed dosage form or medication strength
Oftentimes, an FDA-approved product is available but in a dosage form deemed inappropriate for a specific species or breed; pharmacists are then able to compound the needed dosage form or strength of the medication.5,8 For example, a large-sized chewable treat would not be appropriate for use in a small cat.5 Similarly, while levothyroxine is available in various strengths, a dog will require a much higher number of tablets than a human patient, potentially precluding adherence to therapy. The intended dosage form may also be created to benefit the pet owner as much as their pet. For example, cats do not prefer to take medications in pill form.5 In some cases, medications can instead be formulated as transdermal applications, providing ease of administration to owners who have difficulty getting their cat to take a pill.5,12
Provision of a flavored form of a medication
Medications that are not flavored or sweetened to mask bitterness or cover challenging tastes will likely not be acceptable to veterinary patients.5 Animals tend to prefer flavors that mimic their natural diets.9 For example, cats prefer a fish or tuna flavor over the bubblegum or citrus flavors of commercially available products.9 Pharmacists provide an important service by selecting appropriate flavors (or flavor blends) to ensure pet adherence to therapy.
Compounding Risks for Veterinary Patients
While compounded medications provide numerous benefits for pets, they are not without their associated risks. When extreme care and attention are not taken when preparing compounded veterinary medications, pets are placed at significant risk of harm, which can range from not receiving a therapeutic benefit to experiencing toxicities and adverse reactions.5 It has been noted there is even less regulatory oversight of veterinary compounding compared to that of human compounding.5 The following errors may occur when compounding for veterinary patients:5
Error in preparation, due to compounding technique or inappropriate formulations
Contamination of the preparation
Chemical or physical instability of the preparation
Little to no bioavailability of the preparation in the target patient
The Missouri State Board of Pharmacy found that 20% of compounds reviewed from Missouri licensed pharmacies contained an incorrect amount of the active ingredient, ranging from 0-45% of that indicated on the prescription label.5 Unfortunately, there is little legal requirement requiring tests to demonstrate that a compounded preparation meets the strength indicated on the label. A large amount of data shows compounded preparations are not bioequivalent to manufactured products.5 As one example, veterinary medications are often prepared as transdermal formulations; however, drugs administered via this route lack the bioavailability of their oral counterparts.5
Veterinary Compounding Rules, Regulations, and Oversight
Pharmacists should be cognizant of USP guidelines and the rules and regulations surrounding veterinary compounding. The United States Pharmacopeia (USP) offers guidance pertaining to the preparation of nonsterile (USP <795>) and sterile (USP <797>) compounded preparations, with new guidelines set to be formalized in November 2023.13,14 USP also offers verified, reviewed monographs, around 20 of which relate to veterinary preparations.9 Additionally, various USP chapters are relevant to veterinary compounding, including those focused on stability, quality assurance, calculations, prescription balances, and volumetric apparatus.9
In addition to following USP guidelines, pharmacists should always refer to the laws and regulations of their local regulatory jurisdiction. In terms of legality, the Federal Food, Drug, and Cosmetic Act (FD&C Act) permits pharmacists to compound medications for veterinary patients when the active ingredient is sourced from an FDA-approved drug.8 The use of bulk substances is generally not permitted.8 Bulk substances are used to make a drug that becomes the active ingredient within a finished compounded preparation.8
However, if there is no medically appropriate drug, a compounded preparation may be prepared from a bulk drug substance.8 In April 2022, the FDA issued guidance on this issue, under “Compounding Animal Drugs from Bulk Drug Substances.”8 Through this report, the FDA sought to ensure veterinarians would have access to drugs to treat their patients while making sure animals and humans would be protected from unsafe animal drugs.8 Importantly, Congress passed the Drug Quality and Security Act in 2013. While this increased regulation of compounding for human patients, it does not cover compounding for veterinary preparations.15
Veterinary Compounding Considerations Pharmacokinetic Considerations
Pharmacists who compound medications for veterinary patients need to be familiar with the pharmacokinetic properties (absorption, distribution, metabolism, elimination) of the animals. These properties can differ vastly among and between species and lead to differences in the bioavailability of drugs and their rate of elimination.12 Factors, including the dose, formulation, route of administration, the extent of distribution, plasma protein binding, and rate of elimination, can all affect the ultimate concentration of the drug in the plasma.9,12 Pharmacokinetic differences can not only change the effectiveness of any particular preparation but also cause potential toxicities as well.12
Absorption is defined as the movement of a drug from its site of administration into the patient’s systemic circulation.12 Current data suggests there are not great differences in the cell membrane chemical composition between different species.12 Absorption differences are most important with regard to specific factors, including the anatomy of animals (their length of GI tract).12 Notably, differences in GI tract length can vary significantly even within a species (for example, a Great Dane compared to a Chihuahua).12 Other factors include physiological differences (such as pH differences in the GI tract and gastric emptying times) and differences in the availability of drug
transporters, such as P-glycoprotein.12 As an example of the impact of absorption, a sustained-release preparation of medication useful for humans would be less helpful for animals because of their differences in gastric pH and often shorter intestines.12
Drug distribution is the movement of drugs from the patient’s systemic circulation to their site of action (i.e., tissues).12 It is a significant factor and contributes to pharmacokinetic differences among and between species.12 The distribution of drugs depends on many factors, including blood flow to tissues, relative tissue mass, plasma protein binding, and tissue barriers to distribution.9,12 Because animals have different body compositions, the distribution of drugs to their target sites will differ greatly.9 Table 2 details variations in body composition among different animal species.9
Table 2. Variations in Body Composition Among Selected Animal Species9,10
Metabolic differences among species contribute more to species differences in drug response than any other factor.12 This is a major reason
drugs considered safe for human use are toxic or fatal when utilized in animals such as cats and dogs.12 A common example demonstrating the importance of metabolism is that cats have a very slow rate of glucuronide synthesis, and thus medications that undergo glucuronide formation (such as aspirin) are toxic to them.9 Other drugs and excipients metabolized by this mechanism are likely to be toxic if not fatal to cats.12 This example emphasizes the importance of reviewing all intended ingredients within a formulation prior to including it in a preparation for a specific species. Cats also have issues with alcohols, benzoic acid derivatives, and azo dyes (which may be used as a color tracer in powder formulations).12 Due to this, formulations for cats should also avoid benzene, and compounding pharmacists should review formulation components prior to compounding for feline species.12
Other metabolism examples include the absence of acetylation in dogs.12 Further, many dogs also have significant genetic anomalies which can result in toxicities related to certain compounds.12 A common example is xylitol, which is found in commercially-available gabapentin solutions. When a dog ingests xylitol, the pancreas releases insulin which can result in severe and possibly fatal hypoglycemia.12 Dogs with chronic exposure to xylitol may end up with severe hepatic necrosis.12 Pharmacists should review the ingredients of commercially available products before dispensing such products to canine pet owners.
While renal function is similar among mammals, there are important differences that exist. For example, cats concentrate urine to a greater extent than dogs. Urinary differences in pH also exist.12 Herbivores have more alkaline urine, and carnivores tend to have more acidic urine concentrations.9 These differences may account for differences in renal elimination to an extent.12
When compounding for humans, pharmacists consider unique and specific physiological concerns regarding each patient, and the same process applies to veterinary preparations. Factors such as age, sex, pregnancy status, and the presence of comorbidities should be considered before compounding.9,12 Other considerations include drug or food allergies and the potential for drug-drug interactions.12 For some species, such as cats, the animal's normal behavior must also be considered.9 Cats spend much time grooming themselves; thus, topical medications are likely to be ingested and this should be considered in determining the best dosage form and route of administration.9
USP provides numerous official formulas for veterinary patients. A list of some of these official formulas is detailed in Table 3.9 Pharmacists should be cautious not to immediately translate the use of a formulation intended for a human patient to a veterinary patient.9 Non-veterinary monographs can be used for animals, but these must undergo a thorough evaluation to determine safety and effectiveness and to ensure they meet both patient and species-specific criteria.12 In addition to USP, formulations can also be found in the International Journal of Pharmaceutical Compounding and Trissel's Handbook of Injectable Drugs.9 If no formulation has been identified, it is best to work directly with the veterinarian to determine the appropriate formulation.
Table 3. Official Veterinary Formulas within USP9
|Atenolol Compounded Oral Suspension, Veterinary
|Benazepril Hydrochloride Compounded Oral Suspension, Veterinary
|Buprenorphine Compounded Buccal Solution, Veterinary
|Cisapride Compounded Injection, Veterinary
|Doxycycline Compounded Ophthalmic Solution, Veterinary
|Famciclovir Compounded Oral Suspension
|Pergolide Oral Suspension, Veterinary
|Tadalafil Compounded Oral Suspension
|Zonisamide Compounded Oral Suspension
As discussed, pharmacists may compound for veterinary patients when no effective, FDA-approved product exists. In determining the appropriate formulation, pharmacists need to consider the following as they pertain to the patient: the animal’s size, anatomy, safety, sensitivities or allergies, stress or suffering that can result from administration of large volumes, potential danger to pet or animal owners who must restrain the animal to administer medication, and the potential to minimize side effect and maximize the effectiveness of the therapy.9
Pharmacists should also ask themselves a number of questions to ensure they are compounding in a legal, effective, and safe manner. The following questions should be asked:9
What is known about the physical and chemical compatibility of the drugs?
What is known about the stability of the drugs?
What is known about the pharmacodynamic compatibility of the active ingredient?
What is the overall goal of treatment?
Are similar products available commercially to treat the animal?
Is the animal a food animal?
Will the drug treatment cause a residue problem?
Is there a risk to personnel who handle the drug during compounding or during the administration of the compounded preparation?
Not only does the active pharmaceutical ingredient need to be considered within a compounded preparation but excipients (added substances) do as well.9 Excipient concerns range from eliciting allergic reactions or intolerances to causing serious toxicities and even death. Table 4 details excipients, foods, and drugs that are harmful to various species.16-21
Table 4. Toxic Excipients and Foods by Species16-21
|Food or Excipient
|Ataxia, coma, respiratory depression
|Hypoglycemia, hepatocellular necrosis
|CNS stimulation, seizures, coma
Routes of Administration and Dosage Forms for Veterinary Patients
The same routes of administration used to administer medications to humans are also used to administer medications to animal patients. In addition, there are many devices available to assist with the administration of medications to pets and other animals. Numerous dosage forms can be compounded for veterinary patients, and pharmacists should be skilled in the preparation of forms such as boluses, chewable treats, capsules, oral pastes, gels, and topical dosage forms. This section will detail the oral, topical,
transdermal, parenteral, and nasal routes of administration and associated dosage forms.
The oral route of administration is commonly used to administer compounded medications to veterinary patients.9 This route is normally meant to induce systemic effects but in some cases can be used for local effects (such as with kaolin).15 By compounding oral preparations, pharmacists have the flexibility to adjust the dose, flavor, and/or concentration of commercially- available products.9 The oral route is associated with some disadvantages, in that there is a slow onset of action and the possibility for irregular absorption.9 In formulating oral preparations, pharmacists need to take special care.9
Examples of oral dosage forms include tablets, capsules, liquid preparations, such as suspensions and solutions, pastes, and chewable treats.15 Oral liquids may be preferred as they are easier to administer than tablets and capsules, especially for cats.9 When preparing a suspension, particle size and viscosity should be considered. Useful suspension bases include methylcellulose and simple syrup.12 The use of silica gel as a suspending agent should be avoided in animals that could develop silicate uroliths.12 Oral pastes are also commonly prepared for veterinary patients.9 These compounds have a high viscosity and are useful for animals who have the propensity to allow medications to run out of their mouths.12 Pastes can also be applied to the limbs of cats, where they are licked and then ingested.15 Chewable (medicated) treats are also popular.9 These dosage forms are familiar to pets and can be made for dogs, cats, ferrets, and other species. They are often prepared using pet food as the base.9 Clients should be counseled to store chewable treats out of reach to avoid overdose in the pet.
Chewable treats are a common formulation prepared for pets and an example of a chewable treat base formulation is provided below (Table 5).9
Table 5. Chewable Treat Formulation Example
|Nugget-type animal food
|Gelatin base, melted
|Qs 100 grams
Calculate the quantity of each ingredient required for the preparation
Accurately weigh or measure each ingredient
Pulverize a nugget-type animal food of choice
Melt the gelatin base
Incorporate the powdered animal good and mix well
Add the active drug and mix well
Pour the mixture into molds and allow to set
Package and label the product
Devices for Oral Administration
Similar to pediatric patients, attempting to administer medications to veterinary patients via the oral route can prove very challenging. Table 6 lists various devices to assist with oral administration.9
Table 6. Devices for Oral Administration
|Has a barrel through which a plunger passes that is capable of dislodging a bolus into the gut of an animal
|Resemble large, floating tables and allow the dosage form to float in the intestine and release the medication over an extended period of time
|Single or multiple dose devices capable of delivery preset volumes of liquid into the gullet
|Syringes and tubes that are usually designed to deliver medication directly into the stomach
|Hollowed-out area in which medications that have a heat-sensitive matrix are placed
|Liquid drench guns
|Single or multiple dose devices capable of delivery oral solutions or suspensions of an aqueous or oily nature quickly
|Include paste guns, paste syringes, squeeze bottles, and squeeze tubes that are capable of delivering a specified dose to an animal
|Oral dosing syringe
|Allow liquids to be measured accurately and administered cleanly
|Powder drench guns
|Spring loaded devices capable of delivering required amounts of powder into the back portion of the mouth
|Incorporated into medications that have a controlled- release delivery system
|Water medication- metering devices
|Method of adding medication to the water supply of numerous animals
|Miscellaneous oral dose dispensers
|Droppers, mineral dispensers, mouthpieces, nurses, pump-type dispensers
Topical administration allows for the treatment of localized skin infections and the control of parasites.15 Examples of topical dosage forms include semisolids (ointments, creams, and pastes), dusting powders, and suspensions and solutions.15 Formulations such as foams, shampoos, and rinses are commonly used in the treatment of parasites and ticks. The semisolid base used is an important consideration in determining the rate of drug release from the topical preparation.15
Many devices are used to prevent or remove lice and fleas from animals and to treat skin conditions. Table 7 details available topical devices.9
Table 7. Devices for Topical Administration9
|Convenient way to apply medications
|Used to apply powders to cattle as they brush up against or walk underneath the bags
|Flea and tick collars
|Use slow-release generators containing medications that either have a high vapor pressure or are designed as a solid solution so the product will migrate from the collar over the body
|Percutaneous absorption drug reservoir devices
|Drug containing matrices that allow the drug to diffuse from the device into the animal’s skin or onto the skin surface
|Pour-on, spot-on applications
|Used to treat skin conditions or surface conditions of animals
|Spray race and dip
|Long troughs with deep sides that are commonly used for dipping treatments
|Teat dip applicators
|Immerse the animal completely without injuring it
The transdermal route is an important means of administering various medications to veterinary patients. Transdermal gels are a more complex compounded preparation, and they involve the use of penetration-enhancing percutaneous vehicles (like PLO) which assist in achieving the bioavailability needed for medication efficacy.9,12 Veterinarians will often consult pharmacists to see if they can compound a medication as a transdermal formulation.11 Unfortunately, a limited number of medications are able to be prepared as transdermal formulations. Major considerations in determining whether an active ingredient can be delivered via the transdermal route are the molecular
weight of the drug (with MW > 300 dalton precluding this route), its therapeutic index, and its lipid solubility.9,12 Lipid solubility assists with improving the absorption of transdermal formulations. Drugs with large molecular weights, poor lipid solubility, narrow therapeutic indices, and known human safety issues should not be prepared as transdermal formulations.12 A commonly compounded transdermal formulation is methimazole gel, used to treat hyperthyroidism in cats.12 Below (Table 8) is an example of a transdermal formulation for methimazole 5 mg/0.1 mL in PLO.9
Table 8. Methimazole Transdermal Formulation Example9
|Lecithin: isopropyl palmitate 1:1 solution
|Pluronic F-127 20% gel
|Qs 3 mL
Calculate the quantity of each ingredient required for the prescription
Accurately weigh or measure each ingredient
Remove the plunger from a 3-mL luer lock syringe and attach a tip cap
Pour methimazole powder carefully into the syringe barrel
Add lecithin: isopropyl palmitate 1:1 solution and replace the plunger
In the second syringe measure 2 mL of the Pluronic F-127 20% gel
Attach luer-lok/luer-lok adapter to fit the syringes together and mix contents back and forth between the two syringes
Carefully force all the preparation into one syringe and measure the volume
Remove the other syringe and obtain sufficient gel to volume
Reattach the syringes and mix the preparation back and forth until it is thoroughly mixed
Package and label the preparation
Table 9 lists examples of medications that may be compounded as transdermal formulations.9
Table 9. Medications Able to be Compounded as Transdermal Formulations9
Drugs that are administered parenterally are given via a route other than the mouth (or topically).14 Example routes include intramuscular (IM), subcutaneous (SC), and intravenous (IV). These dosage forms must be prepared using aseptic technique in a sterile environment. Parenteral administration is often a useful means of providing medications to animals, especially in cases where medications need to be administered from a safe distance.8 The following devices are used for the parenteral administration of medications to veterinary patients (Table 10).9
Table 10. Parenteral Administration of Medications9
|Used to treat one animal at a time; can be disposable syringes or ones that can be resterilized
|Used to treat small herds when an automatic syringe is not required; contains several doses
|Used to treat large herds
|Used for unstable drug products requiring the addition of diluent
|Allow injectable formulations to be administered from a safe distance
|Used to insert a drug formulation directly into mammary gland
|Sterile dosage forms designed so a depot of drug can be placed at a site in the body for prolonged release of the drug
When medications are administered via the nasal route, the onset of action nearly matches that of parenteral administration.9 Nasal administration is preferred over parenteral administration in some cases as it does not involve piercing and avoids some of the risks of parenteral administration.9 Examples of medications administered via the nasal route are vaccination and antibiotics.9 Dropper dispensers and spray dispensers are devices usually to deliver medications nasally.
Flavoring and Texture Considerations
Selecting a flavor for a medication that is appealing to the animal while not impacting the stability or safety of the preparation is critical.9 The addition of a flavoring agent should not alter drug bioavailability, solubility, or suspendability.12 In general, animals prefer flavors that mimic their normal diet. Birds tend to prefer sweet and fruity flavors.9 In addition to flavor preferences, birds may also have texture preferences to consider. For example, certain birds prefer movement (such as a wiggly worm) over a particular flavor.9,12 Dogs are omnivores who prefer meat and sweet flavors.9,12 Fixed oils are a great option for canines. Cats, due to a lack of sweet taste receptors on their tongues, do not prefer sweet flavors and also find bitter tastes disagreeable.23 They do better with flavors such as tuna, liver, or marshmallow.9,12 Ferrets often prefer meat and fish flavors but also enjoy sweet flavors as well. Gerbils like sweet and fruity flavors while guinea pigs prefer vegetable-flavored preparations. Finally, rabbits prefer herb, vegetable, or fruit flavors.9,12 Table 11 details flavoring considerations for common animal species. Pharmacists should always consult the pet owner as well to determine any specific flavor preferences. A number of companies provide liquid and powder flavoring agents for pets as well as flavored bases. Dogs and ferrets in particular prefer the taste of oil, and using an almond or similar oil in a preparation provides a neutral, palatable taste for these species.11
Table 11. Flavor Preferences of Selected Species9
|Banana, grape, honey, millet, orange, nectar, tutti-frutti
|Bacon, beef, liver, chicken, turkey, cheese, chocolate (artificial), peanut butter, cod, anise, marshmallow
|Fish, liver, tuna, cod liver oil, chicken, cheese, bacon, molasses, butterscotch, marshmallow
|Chocolate, peanut butter, molasses, honey, fish, fruit punch, strawberries, peas
|Banana cream, orange, peach, tangerine, tutti-frutti
|Carrot, celery, lettuce, pumpkin
|Banana cream, carrot, celery, lettuce, parsley, pineapple, vanilla butternut
In addition to flavoring medications, pharmacists should also consider how best to sweeten their preparations. The following sweeteners (and recommendation concentrations) can be used in veterinary preparations.23
Table 12. Sweeteners for Veterinary Compounds24
|Steviol glycosides 95%
Among all healthcare providers, pharmacists are the only ones able to care for human and animal patients. One of the major roles pharmacists play in the care of veterinary patients is compounding medications to meet the individual needs of these animals. Currently, there is a very limited availability of approved drug products for veterinary species, despite the large need for veterinary medications.5 While the provision of compounded medications plays a critical role in the health of animals, filling a gap in the lack of manufactured drug products, this service comes with an important responsibility to be knowledgeable and appropriately trained in compounding skills and in the various animal species pharmacists are likely to encounter.
Which of the following is a benefit of compounded medications for veterinary patients?
Create a new medication for a specific species or breed
Compound the necessary dosage form or strength of medication for a specific species or breed
Mass manufacture medications
Provide copies of commercially manufactured medications
True or False: Pharmacists are able to flavor compounded medications for veterinary patients to assist with improving adherence.
The Federal Food Drug and Cosmetic Act permits pharmacists to compound medications for veterinary patients when the active ingredient (API) is sourced from
Which of the following is defined as the movement of a drug from its administration site into the patient’s systemic circulation?
Which of the following is an important factor that may impact the distribution of a drug?
Gastric emptying time
Blood flow to tissues
pH differences in the GI tract
True or False: Non-veterinary drug monographs should never be used for veterinary patients.
Which of the following excipients may cause hypoglycemia in dogs and thus should be avoided in compounded preparations for canines?
Which of the following oral dosage forms is preferred for some veterinary patients due to its high viscosity?
Which of the following characteristics of a drug lends itself to be compounded into a transdermal formulation?
Large molecular weight
Narrow therapeutic index
Known human safety issues
Which of the following is true regarding flavoring a compounded medication for a veterinary patient?
Animals have flavor preferences similar to humans
Selected flavoring agents should not affect the bioavailability of the preparation
Cats prefer sweet flavors
Dogs find the taste of oil disagreeable
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Ceresia ML, Fasser CE, Rush JE, et al. The role and education of the veterinary pharmacist. Am J Pharm Educ. 2009;73(1):16. doi:10.5688/aj730116
Bennett SA, Ruisinger JF, Prohaska ES, et al. Assessing pet owner and veterinarian perceptions of need for veterinary compounding services in a community pharmacy setting. Pharm Pract (Granada). 2018;16(3):1224. DOI: 10.18549/PharmPract.2018.03.1224
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Compounding Animal Drugs From Bulk Drug Substances; Draft Guidance for Industry; Availability; Withdrawal of Compliance Policy Guide; Section 608.400 Compounding of Drugs for Use in Animals. Accessed March 23, 2023.
animal-drugs/animal-drug-compounding. Accessed March 23, 2023.
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