#3 Drug-Nutrient and Herb-Nutrient Interactions
Page 1: Introduction to Drug-Nutrient/Herb-Nutrient Interactions
Page 2: Learning Objectives
Understand bidirectional processes influencing drug-nutrient/herb-nutrient interactions.
Recognize important considerations regarding nutrient interactions.
Identify interactions involving macronutrients and micronutrients.
Describe mechanisms behind interactions between drugs/herbs and fat/water soluble vitamins and minerals/trace elements.
Page 3: Establishing Interactions
Interactions can involve micronutrients and macronutrients.
Can lead to nutrient deficiency or toxicity.
Can cause drug treatment failures or toxicity due to alterations in nutrient metabolism.
Cytochrome P450 and drug/nutrient transporters play key roles.
Risk of interactions is higher in:
Pediatric and elderly populations.
Individuals with poor nutritional status (obesity, marasmus).
Those receiving multiple drug therapies or tube feedings.
Page 4: Nutrient Absorption Mechanisms
Active Transport: needs energy to transport against osmotic gradient.
Examples: Glucose, amino acids, calcium, iron, vitamin C, vitamin B1, folic acid.
Facilitated Diffusion: uses transport substances; energy not required.
Examples: Vitamin B2, vitamin B12.
Passive Diffusion: moves down osmotic gradient; no energy required.
Applies to most other nutrients.
Page 5: Consequences of Enzyme Induction
CYP Induction by Drugs
Inactive nutrient metabolites increase nutrient metabolism (victim).
Can lead to nutrient deficiency.
CYP Induction by Nutrients
Inactive drug metabolites increase drug metabolism.
Can decrease drug efficacy.
CYP inhibition has opposite effects, but is rare with nutrients.
Page 6: Pharmacokinetic Parameters and CYP Metabolism
Pharmacokinetic parameters affected by CYP metabolism:
Cmax: Maximum concentration.
Tmax: Time to reach Cmax.
AUC: Area under the curve.
MEC: Minimum effective concentration.
MTC: Minimum toxic concentration.
Metabolism can affect AUC, Cmax, Tmax, duration of action, bioavailability, clearance, and half-life parameters.
Page 7: Interaction Mechanisms and Consequences
Site of Interaction: Delivery devices or GI lumen.
Mechanism: Physicochemical reaction, inactivation, chelation resulting in reduced bioavailability.
GI Mucosa: Changes in transporter/enzyme function alter bioavailability.
Systemic Circulation/Tissues: Change in transporter or enzyme function alters distribution/effect.
Excretion Organs: Can antagonize or impair drug elimination resulting in altered clearance.
Page 8: Classification of Interactions
Precipitating factors (perpetrators): Nutritional status, specific nutrients.
Interaction targets (victims): Drugs.
Consequences: Treatment failure or drug toxicity.
Example: Hyperlipidemia leading to clozapine issues.
Enteral nutrition affecting ciprofloxacin exposure.
Specific nutrients like Vitamin D altering atorvastatin effectiveness.
Page 9: Summary of Drug-Nutrient Interaction Workflow
Factors: Nutrients, Drugs, Patient's Nutrition and Pharmacokinetic Status.
Outcomes: Bioavailability, distribution, clearance, biomarkers, patient outcomes can be negative or positive.
Flow of interactions affects overall nutritional and drug responses.
Page 10: Important Considerations for Nutrient Interactions
Factors affecting nutrient absorption and metabolism including:
Solubility (water or fat soluble).
pH-dependence of nutrient absorption.
CYP enzyme involvement in elimination.
Pre-existing conditions (e.g., CKD, hepatic dysfunction).
The physiologically beneficial window of each nutrient.
Page 11: Vitamin D-Related Interactions
Focus on the interplay between Vitamin D and drug interactions.
Page 12: Metabolism of Active Vitamin D3 (Calcitriol)
Sources: Dietary vitamins D2 and D3, formed by skin exposure to UVB.
Conversion pathway involves liver and kidney to create active vitamin D forms influential in calcium metabolism.
Page 13: Inactivation of Calcitriol
Hydroxylation inactivates calcitriol via CYP3A4.
CYP3A4's flexible catalytic site can be induced or inhibited by various factors.
Page 14: Inactive Metabolite Formation
Inactive metabolites (M1, M2) formation increased post dexamethasone treatment compared to controls.
Minimal effect from prednisone on inactive vitamin D metabolite formation.
Page 15: Ginseng and CYP3A4 Metabolism
Ginseng may inhibit CYP3A4, potentially enhancing anticancer effects when combined with calcitriol in prostate cancer therapy.
Page 16: Vitamin D and Vascular Changes
Potential for aortic calcification with very high vitamin D levels; significant in CKD patients.
Page 17: Implications of Calcitriol Metabolism Modulation
Inducing or inhibiting CYP3A4 affects calcitriol efficacy and toxicity.
Adjustments in drug doses may be necessary based on these interactions.
Page 18: Altered Calcitriol Metabolism
Illustration of active and inactive calcitriol forms.
Various drugs can stimulate or block CYP3A4 affecting vitamin D metabolism outcomes.
Page 19: Low Atorvastatin in Vitamin D Supplemented Patients
Atorvastatin metabolism increases with vitamin D supplementation through CYP3A4, lowering atorvastatin's efficacy.
Page 20: Vitamin K and Warfarin
Vitamin K can inhibit warfarin’s anticoagulant effects. Long-term warfarin therapy can lead to vitamin K functional deficiency.
Page 21: Antibiotics and Vitamin K
Broad-spectrum antibiotics inhibit the intestinal synthesis of vitamin K, leading to potential deficiency.
Page 22: Isotretinoin and Vitamin A Toxicity
Similar structure between isotretinoin and vitamin A leads to potential additive toxic effects such as liver toxicity.
Page 23: Fat Soluble Vitamin Malabsorption
Certain drugs like Cholestyramine affect the absorption of fat-soluble vitamins (A, D, E, K).
Page 24: Folate and Drug Interactions
Drugs like Methotrexate can block folate function, leading to deficiencies and significant health impacts such as neural tube defects.
Page 25: Phenytoin and Folic Acid Interaction
Phenytoin affects folic acid absorption leading to deficiency which increases risk of megaloblastic anemia.
gingival hyperplasia
Page 26: Vitamin B12 Malabsorption
Decreased gastric acid impairs B12 release from proteins, leading to malabsorption.
Page 27: Acid Lowering Agents or Metformin + Vitamin B12
Proton pump inhibitors and Metformin decrease B12 absorption, risking deficiency.
Page 28: Drug-Thiamine Interactions
Antacids and loop diuretics can lead to thiamine deficiency due to impaired absorption or increased urine excretion.
Page 29: Vitamin C-Related Interactions
Aspirin increases urinary excretion of Vitamin C, potentially harming gastric mucosa.
Page 30: Mineral/Trace Element Malabsorption
Acid-lowering drugs impair absorption of crucial minerals, increasing the risk for deficiencies and related health complications.
Page 31: Drugs Affected by Minerals/Trace Elements
Certain minerals can chelate drugs, reducing their absorption and efficacy; must account in drug timing administration.
Page 32: Diuretics Effects on Nutrients
Diuretics can lead to excretion of essential minerals like Mg & K, formerly leading to cardiovascular issues.
Page 33: Interactions with Macronutrients
Drugs can alter metabolic pathways affecting weight and glucose regulation, showcasing the importance of dietary context on drug efficacy.
Page 34: Influence of Nutrition Status on Drugs
Nutritional status can significantly influence pharmacokinetics; malnourished patients may have altered responses to medications due to changes in volume distribution and clearance.
Page 35: Summary
Overview of types and mechanisms of drug-nutrient interactions involving various vitamins, minerals, and pathways.