WATT PoultryUSA - February 2016 - 24
22 ❙ WATTPoultryUSA POULTRY ANTIBIOTICS POLICY Pharmacokinetics vs. pharmacodynamics Pharmacokinetics (PK) is concerned with the time course of antimicrobial concentrations in the body, while pharmacodynamics (PD) is concerned with the relationship between those concentrations and the antimicrobial effect. Suggesting that recommendations on antibiotic labeling may not reflect the best pharmacokinetics for efficacy and avoidance of antimicrobial resistance, Apley said, "We have focused on dose comparisons for the same duration in veterinary and human medicine." And in human medicine, he continued, patients are directed, "Take your antibiotics for as long as your doctor prescribes so that you don't get a relapse with a resistant infection." "Labeled use doesn't necessarily mean judicious use," he said. "It is not necessarily compatible with stewardship. Labeled use is not necessarily the regimen most likely to minimize selection for resistant organisms." Antibiotic dosing regimens have traditionally been determined by PK parameters only. However, PD plays an equal, if not more important, role. - A PK/PD approach to antibiotic therapy "Don't confuse a policy decision to reduce total kilograms of drug with proof that this exposure is the worst exposure to select for resistant organisms." Debate about antibiotics in food animals Beef, pork and poultry producers and their veterinarians, Apley said, need to be actively engaged in the debate that will frame antimicrobial usage for the future. It is a debate that will determine how society weighs incomplete and sometimes contradictory data and resolves conflicting values. It involves policy issues that cannot be resolved on the basis of science or ethical principles alone. "We are going to have to figure out how to move forward without a clearly defined smoking gun or the lack of a smoking gun. And what we get to there is really a disTo learn more on antibiotic use, read: cussion of where lies the burden of proof. Does someAntibiotic resistance not solved by livestock curbs one have to prove that it does cause a problem? Or alone, www.WATTAgNet.com/articles/25090 does someone have to prove that it doesn't?" he said. ■ Space-Ray's BIG FOOT ® Radiant, Gas Poultry Heater Combines Fuel Efficiency With An Extra Large, Rectangular Footprint! 19˚ OPTIMIZED REFLECTOR ANGLE Results In Less Convective Wash Floor Level Litter INFRARED PHOTO Big Foot's extra large, rectangular heat pattern provides uniform heat coverage Ask for free specification brochure CALL TODAY © 2014, GFP Inc. SPACE-RAY ® Division of Gas Fired Products, Inc. Since 1949 Our Angle Is On Performance And Quality 305 Doggett Street, P.O. Box 36485, Charlotte, NC 28236 Toll Free 1-800-849-7311 (704)372-3488 FAX (704)332-5843 Email: info@spaceray.com www.spaceray.com www.WATTAgNet.com ❙ February 2016
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