Pharmacology KNH 413 Most Americans are not meeting RDA. Nutrient deficiencies worsen when medication is taken.

Pharmacology Pharmacotherapy Medicine Prescription and over the counter Pharmacotherapy- use of drugs for treatment of disease and health maintenance. This is an area where nutrition experts can work to prevent drug/nutrient interaction. Medicine- chemical used for diagnosis, prevention, treatment of symptoms or cure Prescription OTC- prescription used to treat the symptoms can also have an adverse effect on individuals nutrition status

Pharmacology Pharmacology Pharmacokinetics Pharmacology-study of drugs, properties and their effects Pharmacokinetics- study of drug absorption, distribution, metabolism and excretion Medication induced nutrient depletion can occur through any of these mechanisms- absorption, distribution, metabolism, excretion

Pharmacotherapy Nutrition affects drug action “Drug-nutrient” interactions Preventing interactions is one part of nutrition assessment/ pharmacotherapy Drug action affects nutrition And position statement—look at what the national organization has done to help practitioners –give information that can be used in practice

Pharmacokinetics Metabolism Biotransformation rendering inactive for excretion via urine or bile Liver major site Through catalyst of enzyme systems Inhibitor – competition for receptor site; increased drug effect Inducer - stimulates synthesis of enzyme; decreased drug effect

Pharmacokinetics Alterations Altered GI Altered distribution Altered metabolism Altered urinary excretion

Pharmacokinetics Altered GI Simultaneous consumption with food Vomiting & diarrhea Interruptions in transit time or surface area Circulation deficits Competition for carriers Simultaneous consumption with food—an example of this would be food and iron supplements Interruption in transit time and surface area- disease state examples- Crohn’s Disease – malabsorpative condition

Pharmacokinetics Altered Distribution Circulation Body size & composition Any situation altering albumin Circulation= examples of factors influencing this would be age and disease Body size and composition - example of how body can alter distribution- body fat may slow distribution Situation altering albumin- liver or kidney disease, malnutriton

Pharmacokinetics Altered Metabolism Age May appear as decreased effectiveness or toxicity Adequate function of organs Genetic factors Gender Concurrent use of other medications Altered metabolism- factor that strongly effects this is age Pharmacokinetics can be seriously altered by function or lack there of- kidneys and liver Gender- female vs. male fluid/muscle mass Polypharmacy- many drugs interacting with nutrients and each other

Pharmacokinetics Altered Urinary Excretion pH of urine Presence of competitor for active transport Urinary flow rates & kidney function Creatinine clearance Urinary excretion creatinine clearance is the volume of blood plasma that is cleared of creatinine per unit of time—useful measure of glomerular filtration rate-GFR

Nutrition on Drug Action Nutrition on drug dissolution pH of stomach Achlorhydria HIV/AIDS Meds Gastric emptying rate Prokinetics Food in stomach Vomiting, diarrhea pH of stomach is altered by Meds such as H2 blockers, proton pump inhibitors, and antacids Gastric emptying rate altered by fat in diet, gastric surgical resection

Nutrition on Drug Action Nutrition on drug absorption Food may affect availability of drug Chelation Compete for carrier systems Inducers or inhibitors of enzyme activity Food may affect availability of drugs- Fosomax and Saquinavir (food reduces absorption) Erythromycin- food increase absorption Chelation-binding – example would be calcium and the antibiotic tetracycline

Stomach acid meds- alter Ca, Mg, Zn, Fe, B12, C NSAID- decrease folic acid, Fe Heart medication- alters electrolytes Diuretics- alter folate, Mg, B6, C, calcium

Complications On Nutrient Absorption Meds that speed transit time or gastric emptying Side effects such as nausea, vomiting, diarrhea, constipation Control urine pH Complications with nutrient absorption can occur –an example would be corticosteriods decrease absorption of calcium

Complications On Nutrient Metabolism Interfere with macronutrient, vitamin and mineral metabolism Increase Urinary output Those effect renal output affect reabsorption Complication with nutrient metabolism may occur with drugs such as- Dilantin which inhibits folate and vitamin D metabolismleadig to megaloblastic anemia

© 2007 Thomson - Wadsworth

At-Risk Populations Elderly Multiple meds – polypharmacy Both OTC and prescribed Physiological changes Compliance Inappropriate dosing Beer’s criteria Beer’s Criteria is inappropriate medicine use in elderly—may need to skip a dose or use smaller doses in elderly due to decrease renal function, obesity, decreased metabolism Consider these measures at age 65 and beyond

At-Risk Populations HIV/AIDS Multiple medications Specific guidelines Significant nutritional side effects At risk population include AIDS patients with AIDS related wasting syndrome—concerns- GI upset with mediation or n/v/d or malabsorption Other concerns- anorexia, depression, apathy, fatigue, financial concerns, metabolic abnormalities, altered fat distribution

At-Risk Populations Nutrition support Tube feedings decrease absorption of some meds Macronutrients may cause chelation of meds Guidelines – ASPEN American Society for Parenteral and Enteral Nutrition (ASPEN) has guidelines (see Niihka under pharmacology) for medication use and nutrition related concerns

Nutrition Therapy Evaluate past and current medical hx Baseline lab measures Treatment regimens OTC, drugs, supplements, and CAM Look at nutrition history for natural origins-dietary supplements OTC medication- over the counter CAM- complimentary and alternative medicine

Nutrition Therapy Potential barriers to compliance Drug-drug interactions among meds Drug-nutrient interactions Overall concerns with nutrition status and medication – Compliance, interactions, between drugs and with nutrients

Clinical Application

Clinical Application Look at need to instruct client on specific nutrient or instruct on taking medication with or without food and timing of certain foods based on medication patient is taking