Drug Nutrient Interactions Flashcards
Type 2 FDI: pharmacodynamic
How the drug acts at target tissue
Binding Enzymes, channels, receptors
How do statins work?
They bind the HMG CoA enzyme system to block the production of cholesterol.
(Pharmacodynamic)
Type 3 of FDI: pharmacokinetic
Time the drug spends in body due to absorption, distribution, metabolism, and elimination.
How does albumin affect drug activity/distribution?
Drugs bind to be transported in blood.
When bound=drug is inactive.
Unbound= physiologically bio active
No albumin–> increases drug toxicity
What is the main metabolic (bio transformation) system for drugs?
Cytochrome P450 system in the liver and other tissues
What are steps and end result of cytochrome P450 system?
Phase 1- oxidize/hydrolyze/reduce
Phase 2- make metabolites water soluble
Either eliminated by kidney as urine or by liver and GI as poop from bile
What is the effect of drug is liver/renal failure occurs?
Excretion decreases; drug toxicity increases
What do appetite lowering drugs do?
Hypogeusia (no taste)
Dysgeusia (changed taste)
N/V
Brain chemistry changed (serotonin uptake stopped, increased NE)
Neoplasm
Antineoplastic
Tumor
Chemotherapy drugs- stop growth of new tumors
What is the effect of cisplatin (antineoplastic drug)?
Causes things to taste badly- dysgeusia
Causes N/V
Chemotherapy Tx
Serotonergic drugs do?
Stop serotonin uptake, increase satiety, and decrease food intake (cause weight loss)
Ex- dexfenfluramine (Fen Fen)
Adrenergic drugs?
Increase satiety and energy expenditure
Decrease appetite and weight
Vasoconstrictor and cause high BP
Amphetamines do?
Higher NE release
Decrease by mouth intake
(Type of andrenergic)
Type 1 FDI: Pharmaceutical
Depends on drug properties
Dose, form, solubility (food increases or decreases)
3 examples that increase weight (sometime appetite):
Corticosteroids ( higher wt and BG)
Megace ® for pt who is wasting away
Propofol (anti anxiety) causes higher wt b/c in TF and emulsion of soybean oil. (Kcal per mL)
Examples that decrease Nutrient Absorption?
Laxatives Have sorbitol (osmotic effect cause diarrhea) Causes vomiting Decreases GI secretions (IF or bile) Change gut pH Damage microvilli (laxatives)
Theophylline (lower nutrient absorption)
Contains sorbitol so causes diarrhea
In a lot of TF
Cholestyramine (lower nutrient absorption)
Binds bile acids so they can’t be recycled
Intention: lower cholesterol
Actually: lower bile means lower fat absorption
Cimetidine (lower nutrient absorption)
Antisecretory
Decreases IF secretion so B12 depletion
How do antacids effect nutrient absorption?
They increase the pH of the GI tract (more basic) and cause it to eliminate more minerals and absorb less minerals
Long term ASA can?
Damage microvilli and decrease Ca and Fe absorption.
What nutrient does chemotherapeutic drugs compete with?
Folate because folate is needed for cell division. Blocks folate so cell division for cancer can quit.
If on Tb drug, INH (isonaizide), what vitamin should be supplemented?
B6 because the INH binds B6
What vitamin does Coumadin interact with?
Vitamin K.
K works to clot blood and warfarin works to prevent blood clotting. Do not eat too much vitamin K if on this drug.
Explain the definition, process and outcomes of MAOIs?
Monoamine oxidase inhibitors- antidepressant
The drug stops MAO from oxidizes/breaking down tyramine in system.
Tyramine vasoconstrictor and causes high BP.
If never broken down, high BP all the time, tachycardia, heart failure.
GOAL: avoid foods with tyramine when on this drug.
Foods with tyramine
Fermented anything Beer Home pickles Aged cheese Smoked meats
What nutrients do laxatives affect?
Lower Ca and K absorption
What type of meds inhibit metabolic enzyme activity (cytochrome P450)?
Renal meds
What compound is in grapefruit?
What products have it?
epoxybergamottin (increase drug availability)
Frozen concentrates, commercial juice, PEEL, squirt, fresca
Fresh pulp only seems safe
What is the grapefruit effect?
Grapefruit juice inhibits enzyme pathways from breaking down/metabolizing statin and calcium channel blocker medications. This increases drug availability by 50% and increases toxicity.
Effect of natural licorice
Glycyrrhizic Acid
Release cortisol, increase Na retention, increase water, high BP (anti diuretic)!
Laxative
AVOID IF ON DIURETIC!
What does Antabuse do?
Used to stop alcoholics from drinking by causing nausea
It stops aldehyde dehydrogenase so aldehyde (breakdown from alcohol) accumulates
Raise tachycardia and BP
Alcohol + fasting =
No gluconeogenesis
Anti-inflammatory drug interactions (steroids)
Decrease Ca absorb (increase excretion)
(Osteoporosis and growth retardation)
Increase protein loss
Retain NaCl so retain a lot of fluids
Prednisone (type of drug, side effects)
Anti-inflammatory drug (retain H2O, less Ca)
Raises blood glucose and weight
Drug induced DM
Anti-inflammatory drug interactions (NSAID)
Causes GI bleeding which leads to
Anemia
What do Loop diuretics (Lasix) do to excretion?
Increase excretion of:
K+ (K wasting) Na Ca Mg Zn Cl
What do Thiazide diuretics (HCTZ) do to excretion of nutrients?
Increase excretion of :
K
Na
Mg
Cl
Saves and re absorbs Ca
What does spironolactone do to k?
K sparing (re absorbs)
Dilantin (Phenytoin)
drug type and what nutrition issues
Anticonvulsant
Decreased folate, vitamin D and biotin absorption
Changes gut pH
Oral contraceptives (nutrition issues)
Increase folate excretion
Increase circulating Vit A and RBP synthesis
Prednisone (drug type and issues)
Anti- Inflammatory
Lower Ca absorption and increased Ca excretion (osteoporosis risk)
High protein loss
NaCl retention (edema)
Increased blood glc and weight gain (DM)
Key nutrient to monitor on diuretics
Potassium!
What might happen to K levels if on Lasix (furosemide)?
K wasting– it will be excreted
So, K levels might fall even more (switch drug if too low)
K wasting diuretics….2 types?
Loop diuretic (Lasix)
Thiazide diuretic ( HCTZ)
What might happen to K+ levels on Alactone (spironolactone)?
K+ levels get higher
K sparing diuretic (re absorbs K in kidney and puts bAck into blood)
If a pt has edema, what might happen to their drug dosage?
Dosage increases because over hydration means a larger volume needs the drug.
Caution: change dosage when edema is gone
What happens to drug dosage when dehydrated?
Lower the drug dosage because less fluid/blood to absorb through.
Low dose doesn’t last long b/c saline drip will be administered.
Propofol (drug type and issue)
Sedative
In liquid emulsion so contains calories
D5W (drug type and issue/why?)
Hydrating solution of dextrose and water.
Contains kcals that need considered in TPN
3 people types who metabolize drugs slowly (lower doses needed)?
Infants
Children
Elders
If CBW is used vs AdjBW for obese drug doses, what could happen?
Increased risk of toxicity b/c adipose tissue slows drug clearance from body and CBW dose would be larger.
2 broad spectrum antibiotic examples, what happens, and what risk increases?
Ampicillin and Gentamycin
Normal bacterial flora in intestine altered
C. Diff risk high
(Diarrhea yellow, acidic, smelly)
What are downfalls of C diff?
Diarrhea serious
Low nutrient absorption and higher excretion
If Cytochrome P450 is not working (liver disease) what is the risk?
Drug toxicity (hepatotoxicity)
2 drug types that cause nephrotoxicity?
Antineoplastics and antibiotics
Drugs that cause hepatotoxicity?
Statins, cordarone, Elavil, methotrexate
