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Nutrient and Drug Interaction lecture 2 new (1).pptx

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Nutrient and Drug Interaction lecture 2 new (1).pptx

  1. 1. Nutrient and Drug Interaction Course code: SHS.515 Lecture: 02 Resource Person: Dr. Noor Younis
  2. 2. A perspective on Drug- Nutrient Interactions SCOPE OF THE ISSUE • There are so many drugs available for use in the human condition, with continued approval of new agents, and expanded indications for existing ones • . Furthermore, our understanding of food components included in the diet, whether nutrients or phytochemicals, has expanded. This makes for an ever-widening potential for interactions between drugs and food, food components, or specific nutrients. • The interaction is considered significant from a clinical perspective if the therapeutic response is altered, or nutritional status is compromised.
  3. 3. APPROACH TO DNIs Classification The classification of DNIs can be approached in a variety of ways • by drug • by nutrient • by patient type • by outcome (clinical manifestations) • by mechanism (chemical or physiologic) • or by location (gastrointestinal [GI] tract, circulation, and site of effect
  4. 4. APPROACH TO DNIs A classification system based on the location and mechanism of interaction, with both an identified precipitating factor The above-mentioned approach would allow DNIs to be described or examined based on five general categories described or examined based on five general categories: 1. The impact of nutritional status on drug disposition and effect. 2. The impact of food on drug disposition and effect. 3. The impact of specific nutrients on drug disposition and effect. 4. The impact of drugs on nutritional status. 5. The impact of drugs on the disposition and effect of specific nutrients.
  5. 5. Mechanisms • Why certain drugs and nutrients interact with each other and not with others, relates to physicochemical factors of the medication, food or nutrient, as well as to individual physiology whether normal or disordered. • At the level of the GI tract, interactions may be due to physicochemical reactions, as well as altered enzyme or transporter function. • Specific drugs may alter nutrient intake, absorption, storage, metabolism, and excretion. Non-nutrient agents (herbals and other dietary supplements) have the same potential to alter nutritional status and nutrient disposition,
  6. 6. Impact of Nutritional Status and Food Intake on Medications • Both protein-calorie malnutrition and obesity are known to influence drug disposition and effect • Several micronutrients including riboflavin and ascorbic acid are active components in microsomal enzyme systems used for drug metabolism with capacity reduced in deficiency • Although vitamin A deficits may slow drug metabolism in animal models, this remains poorly defined in humans • However, it may not even require a clinically apparent alteration in nutritional status for dietary changes to influence drug response particularly when underlying gene polymorphism plays a role.
  7. 7. Approaches to Drug-Nutrient Interaction
  8. 8. Impact of Drugs on Nutritional Status • The impact of drugs on nutritional status or on the status of a specific nutrient has been well recognized • Drugs can influence nutrient absorption, distribution, metabolism, and excretion. • However, a few situations account for most clinically common nutrient depletions—when a drug causes significant anorexia or malabsorption • Even the anti-vitamin effects of a medication may be due to one or more factors—reduced absorption or reduced conversion to active form, interference with vitamin-dependent pathways, or increased vitamin clearance (metabolism or excretion)
  9. 9. Continue… • These are each more likely to occur when used chronically, and in patients with marginal nutritional status. • DNIs are assumed to play negative roles in patient outcome, but some interactions can improve therapeutic outcome. • There may be as yet unrecognized adverse nutritional effects to a given drug. Recognized drug effects can include a reduction in appetite or absorption, alteration of nutrient metabolism, and increased urinary losses, whether used for a short or longer duration
  10. 10. Adverse Drug Effects Following Nutrient Losses • The idea that some adverse effects of medications are directly related to their influence on nutrient status is not new • In other words, adverse effects of the medication may occur through an alteration of nutrient status. So, drug-induced nutritional deficits may be considered as a subclass of adverse drug effects, whether identified as dose-related, or duration-related. • For example, valproic acid hepatotoxicity may be related by a common mechanism involving drug-induced alteration in the methionine cycle • Similarly Antiepileptic agents are likely to alter the status of several nutrients, including folic acid and biotin.
  11. 11. Drug Disposition and Response • Pharmakokinetics Pharmacokinetics is important for understanding or predicting the magnitude or duration of an effect of a drug or nutrient. A substance can produce an effect only if it can reach its target(s) in adequate concentration. Several factors can affect the absorption and
  12. 12. Absorption The route by which a substance is introduced into the body affects its pharmacokinetics common routes of administration are listed below SYSTEMIC ROUTES Systemic routes of administration are those that deliver the substance with the intent of producing a systemic (on the system) effect, rather than a local effect on, for example, the skin.
  13. 13. A subdivision of systemic route of administration is parenteral, which refers to systemic routes other than oral, sublingual, buccal, or rectal, which are termed alimentary routes. Oral administration is generally the simplest, most convenient, safest (because of slower onset of drug effect and ability to reverse a mistake), and often most economical route of administration. Most drugs are well absorbed from the gastrointestinal (GI) tract. The rate and extent of absorption is a function of the physiochemical properties of the drug substance (e.g., hydrophilic, lipophilic), its formulation (e.g., tablet, capsule, liquid, physiological environment (e.g., stomach pH), and any metabolism in the gut wall
  14. 14. Alteration of any of these features that occurs, for example, as a result of change in diet, lifestyle, age, or health status, can affect absorption Nutrients and foodstuffs can affect absorption by direct binding or by altering the physiologic environment (e.g., pH of the stomach contents). The simple act of food ingestion, or even its anticipation, can release digestive enzymes that inactivate certain drugs, such as penicillins. The intravenous route of administration delivers drug substance directly into the bloodstream.
  15. 15. The intravenous route bypasses problems of absorption from the GI tract, allows for rapid adjustment of dose to effect, can be used even if the patient is unconscious and avoids the “first-pass effect” Subcutaneous administration involves the delivery of the drug into the tissue beneath the skin for subsequent entry into the vasculature. Intramuscular administration is generally rapid because of high vascularity and provides an opportunity for sustained release formulations such as oil suspensions Inhalation provides one of the most rapid routes of drug administration due to the large surface area and high vascularity of the lung.
  16. 16. • Other systemic routes include intraperitoneal, which is particularly useful for the administration of drugs to small animals • Systemic routes of administration provide an opportunity for drug and nutrient/food interactions at several levels, including: the rate at which drug substance or nutrient is available for absorption (e.g., dissolution rate, degree of ionization, adsorption, etc.); the extent of plasma protein binding; and the rate or route of metabolism.
  17. 17. TOPICAL ROUTES • Topical routes of administration—such as direct application to the skin or mucous membranes—for the purpose of local action are not generally sites of interaction between drugs and nutrients/food. OTHER ROUTES Eye (ophthalmic administration) Ear (otic administration) Nerves (intraneural administration) Spinal cord (e.g., epidural or intrathecal administration) or Brain (e.g., intracerebroventricular administration) do not often lead to significant nutrient/food interactions,
  18. 18. FACTORS THAT AFFECT ABSORPTION The rate and extent of absorption are influenced by many factors related both to the characteristics of the drug or nutrient substance and the particular characteristics of the recipient at the time of administration For example, the product formulation generally determines the rate of dissolution under specific physiological conditions, but these conditions depend on the person’s state of health and other factors, such as diet. The solubility of the administered substance, its dosage, and route of administration also affect absorption.

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