Tuesday, April 29, 2014

Drug Compounding--A Veterinarian's Comments-Dr Colleen Currigan

Drug compounding is not new, but there have been some recent high profile events, both in the human and the veterinary world, that have brought the issue back into prominence. These include the 2009 deaths of 21 polo ponies at the U.S. Open Polo Championship in Florida after an error was made when mixing a compounded medication for the ponies, and most recently the 2012 outbreak of human fungal meningitis, when contaminated medication was dispensed to physicians around the country from New England Compounding Center. These events may lead to legislative changes that affect the compounding of medications in veterinary medicine and those changes could impact the prescribing of medications for cats.
What exactly is ‘compounding’? My recent involvement on the American Veterinary Medical Association’s (AVMA) Clinical Practitioners Advisory Committee has taught me a lot about the ins and outs of compounding. The AVMA is working hard to educate veterinarians and pet owners about compounding by posting information on their website, www.avma.org, as well as holding educational webinars for veterinarians. Much of the information that I am including in this blog article came from the AVMA. Below are some compounding facts:
  • Compounding is the manipulation of a drug beyond that stipulated on the label. Examples include mixing, diluting, concentrating, flavoring, or changing a drug’s dosage form, in order to tailor the drug for a specific patient. In the cat world, compounded medications are widely used. Why?
    • Many of the drugs that we prescribe are not available in a strength that is appropriate for a cat. Thus manipulation of that drug is the only way we can dose it correctly for a feline patient
    • Knowing that cats can challenge the best of us when it comes to being medicated, unless we can somehow manipulate a drug to make it more acceptable to the cat (‘if it’s tuna flavored, I’ll consider it’), we run the risk that some of our patients simply will not get needed medication.
    • In other cases, a patient may resist oral medications altogether, no matter how the medication is manipulated. In these cases, there are some medications that can be made up into a gel that can be applied topically on the inside of the cat’s ear (known as a ‘transdermal’ or ‘across the skin’ application of drug). A very limited number of drugs have been studied and shown to work when given by this route, but one that is used commonly to treat overactive thyroid conditions in cats (methimazole) usually works quite well when given by the transdermal route.
  • Compounding is regulated by both the federal government (FDA, or Food and Drug Administration) and state governments.
  • Compounded drugs are not the same as generic drugs! A generic drug is a non-brand-name version of a drug. Generic drugs are approved by the FDA.
  • Compounded drugs are not FDA approved drugs. Even though compounding involves manipulating or tweaking already approved FDA drugs, when a drug is compounded, the new form may or may not perform in the same way as the approved drugs.
  • The major issues regarding compounding in veterinary medicine center around the use of ‘bulk ingredients’ when making these medications, rather than using approved FDA drugs. ‘Bulk’ means ‘raw’ chemical ingredient that is actually intended for manufacture into a finished FDA approved form. Because a bulk drug is unfinished, it does not carry FDA approval. Sources of bulk ingredients include China and other locations outside the U.S. Compounding of drugs from bulk substances for use in animals is currently illegal, though not well enforced.
    • Are there occasions when we have no choice but to use a medication compounded from bulk ingredients? Yes! AVMA and veterinary practitioners are advocating for the use of bulk compounding, but only under specific appropriate circumstances, including:
      • The approved drug is not commercially available. Drug shortages are commonplace in human and veterinary medicine. In those cases where there may not be a reasonable temporary alternative FDA approved medication that is available for compounding, compounding from bulk may be the only option.
      • The needed compounded medication cannot be made from the approved product, as is the case with the transdermal gel, methimazole, mentioned above. Additionally, flavoring cannot mask the objectionable taste perceived by cats of some approved drugs, necessitating compounding from bulk product in order to successfully administer these drugs at all to cats.
      • There is no approved product from which to compound the needed medication, and there never will be. An example is a drug called ‘cisapride’. This medication is commonly used to treat chronic constipation in cats. It was available many years ago as a human product, but is no longer being made.
    • Unfortunately, compounding to decrease cost (to the veterinarian and to the pet owner) by using bulk ingredients when an FDA formulation is available and appropriate is illegal and constitutes manufacture of ‘mimic drugs’ (drugs that are produced to copy an FDA approved drug by avoiding the time consuming and costly drug approval process)
Where does this leave the feline doctor and the cat owner? As veterinarians, our responsibility is to make sure we are utilizing compounding pharmacies that follow the rules, are appropriately licensed, are reputable, trustworthy and that utilize best practices. Because quality control of a compounded drug is less than that of an FDA approved drug, our homework also includes having compounding pharmacists provide evidence to support the stability, safety, and efficacy of their products.
Objective therapeutic monitoring (following thyroid levels, blood pressure measurements, etc.) is critical when using compounded medication in our patients. Monitoring at home by cat owners is also important when using compounded (or even FDA approved) medication. This is especially important when using drugs (such as pain medication) with effects that may be more difficult to objectively monitor. Pain is hard to assess in cats. Since there is no objective way to measure it, if a compounded pain medication is utilized in patients, close observation of patient behaviors at home by the cat owner is especially important. Owners should never simply assume that if pain medication is given, pain is always relieved (and this holds true for FDA approved, as well as compounded, medication).
In most cases, the benefits of using compounded drugs, when appropriate and necessary, greatly outweigh any risks. In feline medicine, we would have many patients that either received no medication or all, or received it with much difficulty and perhaps erosion of the human animal bond, without the use of compounded medications. Cat owners should also be aware that there is a cost when using medication compounded from approved FDA product rather than from bulk because the FDA drug is more costly than bulk and because more labor is involved in tweaking the drug than if bulk was used.
As a feline practitioner, I will continue to use, and advocate for use of compounded medications in my patients when that is the best option for the patient and the patient’s owner, but I will also do what I need to do to make sure that that medication is safe, effective, and being made legally.
quoted from here

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