Many clients are requesting all natural and alternative treatment options as they are under the impression that they produce
less adverse effects than pharmaceutical compounds. This is a common misconception as some of the most toxic compounds known
are natural products such as botulinum toxin, ricin, cobra venom, and uranium, among many others. It is important to discuss
with clients all medications that an animal is on, including dietary supplements as they can have adverse effects and drug
interactions similar to pharmaceutical compounds. St John's wort is a hepatic enzyme inducer (cytochrome P450) that can reduce
the effectiveness of some drugs such as cyclosporine, digoxin, diltiazem, and vincristine among others. In contrast, grapefruit
juice extract is a hepatic enzyme inhibitor (cytochrome P450) that can result in drug toxicity with drugs such as cyclosporine,
digoxin, diltiazem, and vincristine among others.
Many pharmaceutical compounds in use are purified naturally occurring compounds or are commercially synthesized compounds
that occur naturally. Many other pharmaceuticals are semi-synthetic in which a natural compound has been modified to produce
a more favorable pharmacologic compound. Some important semi-synthetic compounds include aspirin, cephalexin, cefazolin, clindamycin,
and amoxicillin. In contrast some pharmacologic compounds are completely synthetic including the fluoroquinolone antimicrobials.
It is important to realize the benefits and limitations of dietary supplements and "natural" products. Most of these products
are not approved by the FDA and have not been demonstrated to be safe and effective in controlled clinical trials. Some compounds
have undergone limited trials, but none of them have undergone the scrutiny of an FDA trial. Another important point to remember
is that most of these products are not subject to Good Manufacturing Practices demonstrating the purity and potency of the
final product as mandated for FDA approved therapeutics. The manufacturers of dietary supplements are not required to assess
stability of the active ingredients, therefore they may decrease in effectiveness over time. Stability of some compounds may
be as short as a few hours depending on their manufacturing process. Another consideration is the potency of an active ingredient
may vary batch to batch due to source of product, time of harvest or collection, and strain differences.
