Notes from SWOSU Faculty--Compounding Tips for Specific Animals

Compounding Tips for Specific Animals

Compounding liquids for veterinary use often focusses on concentrating the medication and ensuring that the dose is measurable.

Canine -- Dogs typically exhibit a preference for fixed oils (such as vegetable oils), so that medications may be suspended or dissolved in such a vehicle.  The drug may be flavoured with 3-5% chicken, beef, liver, or cheese flavours.  Many dogs also enjoy sweet flavours, so that saccharin or some other sweetener (Stevia powder extract) may be added.  Chocolate flavouring that does not contain theobromine may also be used as a sweetening/flavouring agent.Feline -- Cats also prefer fixed oils.  A good vehicle is cod liver oil, since the fishy odour may appeal to many cats.  Other oils may be used to which specific flavouring agents have been added (summarised below).  Fish flavour (3-5%) may be used or, alternatively, the medication may be placed in a "triple fish" suspension (tuna, salmon, and sardines, pureed with xanthan gum and a preservative).
Avian -- Birds typically require small drops, so the drug must be very concentrated and, typically, sweet.
Livestock -- As noted above, pastes are often used in dosing large animals.  These may be prepared using an anhydrous polyethylene base, flavoured to improve palatability.  Alternatively, the medication may be incorporated as a feed with 47% sugar and 3% dry apple powder flavour.

Other Dosage Forms

Solid dosages forms may be prepared for use in small or large animals as a flavoured troche or biscuit, to be used as a "treat" for the animal.  Troches are prepared as they are for humans.  Biscuits may be prepared by incorporating the drug into a dough of wheat germ, powedered milk, and a flavouring agent, rolled and cut to obtain appropriate doses, and baked or dried.Percutaneous patches may be prepared by placing the drug in a pluronic lecithin organogel, applied to the skin.
If a pet (dog or cat) will not take medication by any other means, some veterinarians and pharmacists have been successful in formulating a paste that is placed on the animals paws.  The animal does not like to have dirty paws and will consequently lick the paste off, thereby providing an oral dosage route.

Compounding in General

Suspensions -- Suspensions are prepared as they would be for human medicine.  Common suspending agents include micronised silica gel, 2% magnesium steareate, carageenan and 0.5-1% methylcellulose gel.Pastes -- Pastes are often prepared using either anhydrous polyethylene base or 4-5% methylcellulose gel. 


Sweetening agents most often used are 0.05% saccharin or 0.1% stevia powder extract.  Sweeting agents will often be employed to mask the bitter flavour of the drug. 
 
Topical compounds -- One unique aspect of topicals in veterinary practice is that animals will often lick the compound off.  In this instance, when lick is NOT desired, a bitter agent will be added to the formulation to discourage licking.  Quinine or other pharmacologically active agents have been used.  However, the preferred bittering agent is sucrose octaacetate (which is pharmacologically inactive) in a 1-5% concentration.  Alternately, the drug may be placed in cellulose acetate hydrogen phthalate (the same substance used as enteric coatings) which will provide a protective seal over the topical medication.  Topical dosage forms include solutions, gels, creams, or ointments, prepared as with human meds in the form most appropriate for the drug and its intended use.

Flavours 
Many species show a marked preference for specific flavours.  Flavours that have proven useful in veterinary practice are summarised in the following table:

Canine	liver, beef, chicken, cheese, artificial chocolate, peanut butter, malt, molasses, cod liver oil, raspberry, strawberry, marshmallow
Feline	fish, tuna, sardine, salmon, cod liver oil, beef, liver, chicken, molasses, peanut butter, butterscotch, cheese
Avian	tutti frutti, pina colada, tangerine, grape, orange, banana, raspberry, millet
Equine	apple, apple/caramel, caramel, cherry, alfalfa, clover, sweets
Bovine	eggnog, anise, alfalfa, maple, molasses, clover
Porcine	anis, anisette, cherry, sarsparilla, licorice
Caprine	molasses, apple, caramel
Poultry	watermelon, vanilla, butternut, corn, milk
Reptiles	lemon custard, banana cream
Iguanas	cantaloupe, kiwi, orange, watermelon, banana
Rodents	lemon custard, banana cream
Ferrets	chocolate, peanut butter, fish, beef, fruits, molasses
Gerbils	orange, peach, tutti-frutti
Guinea Pig	celery, pumpkin
Rabbit	carrot, celery, lettuce, banana cream, vanilla, butternut, pineapple
Chinchilla	banana
Ratites	Bright colours: yellow (emus) and green (ostrich).    Flavours (emus): watermelon, kiwi, honey, cantaloupe, strawberry
Primates	banana, raspberry, apricot, orange, peach, chocolate
Armadillo	liver, beef, canned dog food
Elephant	apple
Tiger	liver, beef, chicken
Zebra	apple

  
 Flavours that are available for compounding include the following (OS/OM and WS/WM refer to oil or water and soluble or miscible): apple powder WM, apple-ade liquid WM, beef liquid OS, beef liquid WM, cheese liquid OM, cheese liquid WM, chicken liquid WM, chicken liquid OS, chicken-herbs & spice liquid WS, fish liqiud OS, liver liquid OM, liver liquid WM, and liver powder souble.  Alternatively, meat-flavoured gravy mixes may be used extemporaneously. 
 

Legal Responsibility in Veterinary Compounding

Compounding of existing drugs is permitted if specific criteria are met.  Compounding is technically illegal if bulk drugs are the source.  However, the FDA has adopted the view that it is permissible IF the veterinarian states
1) there is legitimate medical need 
2) compouding is needed for an appropriate dosage regimen for the species, age, size, and medical condition 
3) the product is not available in either veterinary or human form or if a different excipient is required for successful treatment.
The following assurances should also be made when compounding:
1) The medication is compounded by a veterinarian or pharmacist 
2) A withdrawal time be established if appropriate 
3) The pharmacist follows good compounding practices 
4) The pharmacist must include on the label
a) name/address of the DVM 
b) active ingredient 
c) date dispensed and expiration date (generally the end of therapy) 
d) directions for use including the target species 
e) cautionary statements, including withdrawal times for milk, slaughter, and egg, where  appropriate 
 f) dispensing information (pharmacist, store, location)
ALL prescriptions should contain the statement "Caution: Federal law restricts this drug to use by or on the order of a liscenced veterinarian."
In examining inappropriate dispensing, the FDA views with a suspicious eye the following: "independent" compounding, compounding of available drugs, compounding drugs that have been withdrawn for regulatory reasons, R.Ph. recommended compounding, the use of "trade" names, colours, or flavours that state or imply improved efficacy, solicitation of compounding business, compounding of large quantities, failure to adhere to withdrawal times, and large volume compounding of "out of stock" medications.

Drugs that are banned from use in food animals include the following: chloramphenicol, clenbuterol, DES, the nitroimidazoles (dimetridazole, ipromidazole), furazolidone, nitrofurazone (topical is permitted), fluoroquinolones, and vancomycin.  Additionally, the sulphonamides are contraindicated in lactating animals except those specifically approved for such use.Prescription Interpretation -- Reading veterinary prescriptions is generally the same as that encountered in human medicine.  However, one abbreviation that is unique in veterinary practice is s.i.d., which is interpreted as once a day.  Therefore, a script reading digoxin 0.125 mg s.i.d. would be interpreted as digoxin 0.125 mg once a day.

Veterinary Drug Approval Process 
The process of drug approval by the FDA is similar to that for human drugs.  However some specific differences do exist.  Potentials drugs are classified as Investigational New Animal Drugs (INAD) and applications for use are made under a new animal drug application (NADA).  These (or pre-INAD) applications are made to the Centre for Veterinary Medicine (CVM) of the FDA.  New drugs must prove safety and efficacy in at least two well-controlled studies, including clinical trials.  The CVM reviews that data, ensuring GLPs and the integrity of the data.  As with the human approval process, a category does exist for drugs not yet approved.  In life-threatening situations, a private practitioner or zoo veterinarian may apply for an Expedited Compassionate Investigational New Animal Drug Exemption (ECINAD).  If approved, the ECINAD must comply with routing/receipt requirements as set forth by the CVM. 
 

Small Animal Handling 
Care should be taken when handling small animals to reduce the injury that has already occurred or to minimise the risk of injury by the caretaker.  However, in many instances the animal must be restrained in order to examine or administer medications.  Ideally, restraint of small animals should employ two individuals.

Dogs -- One person may gently lean over the haunch of a larger dog, holding the front paws with their hands, allowing a second person to examine or administer medication.Cats -- The presence of extremely sharp claws present an added difficulty in handling cats.  Often, a cat may be restrained by gently pinching the skin between the head and shoulders (this may be done manually or by placement of a device such as clothespins).  This is similar to the manner in which queens will carry a young kitten and may effectively restrain the cat.  Another effective means of feline restraint is to place the cat on a towel or blanket, QUICKLY folding the towel over the animal's back, making sure the paws are kept within the towel.  This will leave the head exposed for oral dosing.
Direct Oral Dosing of Small Animals -- The medication should be placed as deeply into the mouth as possible.  The jaws should be gently opened by applying pressure on the joint.  When the mouth is opened the medication is placed deep within the animals mouth.  With solid dosage forms, the placement may be made by placing the tablet/capsule on the tongue and gently pushing to the back of the mouth with a finger (holding the jaws open with the other hand).  If liquid dosage forms are being used, a medicine dropper is ideal to place the liquid at the back of the mouth.  Once in place, the animal's mouth is closed and the throat is gently rubbed to aid in swallowing the medication.

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