Drug Nutrient Interactions Flashcards
DNI Classification Type I
Ex vivo. Interactions occur outside the body
DNI Classification Type II
Absorption phase. DNI’s that alter the bioavailability of the drug. Occurs primarily in the GI or mucosa.
DNI Classification Type III
Physiologic Action
Alteration in kinetics (metabolism, distribution)
DNI Classification Type IV
Elimination Phase
DNI Classification Steps.
- Identify the precipitant agent
- Identify the object agent
- Identify the MOA
- Predict the clinical outcome
- Consider management changes
Differentiate between incompatibility and instability.
Incompatibility means the DNI is a physical interaction (i.e. precipitation) and instability means the DNI is a chemical interaction (i.e. maillard reaction or glycosylation)
What are drugs that cause stability issues in PN solutions?
H2 blockers Insulin Folic Acid Iron Dextran Heparin Ascorbic Acid Octreotide L-Carnitine Thiamine Albumin L-Cysteine
What type of insulin can be used in PNs?
Regular Insulin
Humulin R, Novolin R
What H2 blocker is preferred in PNs?
Famotidine and cimetidine
What is the concern with calcium and phosphate?
Precipitation (solubility risk)
What are some ways to prevent precipitation of Ca and Phosphate?
The higher the AA concentration the better. Acidic pHs. Keep at low temperatures When mixing add Ca last. Don't add electrolytes via Y-site. Don't mix with 3:1 PNs
What amino acid solutions are good to prevent calcium and phosphate precipitation?
Aminosyn II and Clinisol 15%
What is a way to improve TNA Solution’s (3:1) compatibility/stability?
Dual chamber bag, but there can be lipid contamination.
What is the most important vitamin to supplement?
Thiamine
How often do you give B12 during a vitamin shortage?
Monthly
During trace element shortages what elements are the most important to supplement?
Zinc
Selenium
Copper
Why is a Neonatal/Pediatric TNA (3:1) risky?
Because of high calcium and phosphate concentrations.
What is placed in Pediatric TNAs to help with Ca/Phos issues?
L-cysteine
It is a conditionally essential AA and it acidifies the TNA.
Why is calcium and phosphate included in pediatric TNAs?
For bone growth
How many micrograms of aluminum are allowed to be in large volume parentals (LVP’s)?
25mcg/L
What did the FDA establish as a safe amount of aluminum?
5mcg/kg/day
What is considered toxic levels of aluminum?
60mcg/kg/day
What can excess aluminum cause?
Liver disease
What patient populations are considered “High Risk” for aluminum contamination?
Renal disease
Neonates, specifically premature
Long-term PN therapy, especially ones with high aluminum content
What are the major sources of aluminum contamination?
Phosphate, Acetate, Gluconate salts
To avoid aluminum contamination should NaPhos be used or KPhos?
NaPhos because the K+ salt
Besides tapering down by 1-2 hours what else can be used to taper a patient off a PN?
Dextrose containing fluid
What size filter do you use for a 2:1 PN? 3:1?
- 22u for 2:1
1. 2u for 3:1
What are some ways to avoid catheter-related occulsions?
Dedicated line for PN Don't use incompatible meds in a Y-line Alteplase for thrombus Ethanol for lipid build-up HCl or cysteine for Ca/Phos
Can you give calcium, phosphate, or magnesium salts via Y-site with PN therapy?
No. Ca, Phos, and Mg salts cannot be given via Y-site with PN therapy.
What are some drugs that are incompatible with both 2:1 and 3:1 PNs?
Midazolam
Phenytoin
Sodium Bicarbonate
What are some drugs incompatible with 3:1 PNs?
Heparin
Iron dextran
Hydromorphone
What are some drugs incompatible with 2:1 PNs?
Some lipid soluble medications
_____ drips may be co-infused if venous access is limited.
Insulin
What interaction can cause life threatening IV or pulmonary issues?
Calcium and ceftriaxone precipitation.
What patient population is a PN containing calcium and someone getting IV ceftriaxone contraindicated?
Neonatals
If you were going to sequentially administer Ca and ceftriaxone what must you do?
Flush the line
What are some options to prevent DNI with ceftriaxone administration?
When initiating PN with patient on ceftriaxone withhold calcium from PN for 48 hours after last ceftriaxone dose. (not a good option for neonates needing calcium)
You can also use cefotaxime instead of ceftriaxone.
What type of DNI occurs with feeding tubes and feeding formulas?
Type I
When giving hypertonic/hyperosmolar medications into the small bowel what is a way to prevent DNI adverse effects?
Dilute with 10-30mL of sterile water.
When changing medication to a liquid dosage form what form is preferred?
Elixir and suspension is favored over a syrup.
If there is gastric distress what must you check when turning a medication into a liquid for enteral administration?
Sorbitol content
What do you do before and after administration of an enteral medication?
Flush the tubes
When administering drugs what must you do between each medication?
Flush
Can you add drug to an enteral nutrition formula?
No
If there are high gastric outputs and you’re administering an enteral medication which area is preferred for administration?
Small bowel
When administering to the small bowel what dosage form is more favorable?
Ones not requiring dissolution
If a medication requires an acidic environment can you administer it directly to the jejunum?
No, the jejunum is basic.
What are some issues with feeding tubes in the small bowel?
Some drugs need an acidic environment
You can bypass the primary absorption site of some drugs
You can bypass the site of action of drugs
You can improve the absorption of some drugs (need to decrease normal dose)
What are some drugs that need an acidic environment?
Ketoconazole, itraconazole, ferrous sulfate, and tetracycline
What drugs’ absorption site is bypassed with a feeding tube in the small bowel?
Ciprofloxacin (primary site is duodenum)
Zinc, copper, selenium, iron
Why is digoxin’s absorption improved with a feeding tube in the small bowel?
It bypasses it’s acid hydrolysis step
What are medications you need to avoid with enteral tube feedings?
Carcinogenic/cytotoxic-can release aerosols
Mineral oil-viscous and a high potential for TF clogging
High acid medications (pH
Why do you need to avoid sorbitol in liquid medications?
It can cause diarrhea.
What can digoxin to in TF?
Digoxin can reduce the absorption of fibers
What is the DNI with levothyroxin?
Thought to be an interaction with soy protein in the formula and/or adsorption to the tube
What is phenytoin’s DNI?
Adsorbs to the tube or EN component
How can you help prevent DNI’s with phenytoin?
Hold the TF 1-2 hours before and after. The key is to use be consistent with how long you hold it.
Dilute the suspension to twice daily to reduce the time the EN is held.
Monitor serum phenytoin
What is the DNI with carbamazapine?
Binds to the tube
How can you avoid carbamazapin’s DNI?
Dilute the suspension to 1:1 to improve the bioavailability
You can slow the gastric emptying time and avoid post-pyloric administration.
Hold TF
Monitor b/c of narrow therapeutic window
Is carbamazapine a highly basic or highly acidic stable drug?
Acidic
List these fluroquinolones in order from greatest to least in their potential for DNIs: levo, ofloxacin, cipro.
Cipro>levo>ofloxacin
If giving an enteral dose of cipro what is its equivalent in an IV dosage?
450mg
Why can cipro suspension not be given via FT?
Adheres to the tube
Why is there potential interactions with fluroquinolones and enteral nutrition (EN)?
Fluroquinolones bind cations
Why is there a problem with jejunal feeding w/ ciprofloxacin?
Cipro’s primary site of absorption is the duodenum.
What is warfarin’s DNI issue?
It can bind to protein, decreasing its bioavailability.
When dealing with warfarin what is the recommended amount of vitamin K/1000 kcal’s?
Can you crush omeprazole, why or why not?
No because it contains an enteric coating.
How do you prepare an enteric coated PPI for EN?
You dissolve the pellet in Na bicarbonate 8.4% (basic) and then administer it via gastric tube or small bowel tube.
How do you take alendronate and risendronate?
Avoid food w/in 30 minutes of drug administration, remain in upright position for 30 minutes; take only with water.
How does food affect saquinavir, grisiofulvin, and posaconazole?
Food increases their absorption, therefore you take within two hours of a meal.
What nutrient interaction does grapefruit juice have?
Inhibitor of CYP3A4
What nutrient interaction does St. John’s Wart have?
Induces P-gp and CYP3A4.
What nutrient interaction does ascorbic acid have?
Acidifier and reducer. This enhances iron absorption.
What nutrient interactions do dairy products/multivalent cation containing supplements (calcium, magnesium, iron, and aluminum) have?
They decrease the absorption of tetracycline and fluroquinolones.
What nutrient interaction do foods high in fiber have?
Decreases digoxin’s absorption
What interaction does sulfasalazine have?
Impairs folic acid absorption
What does prolonged use of acid reducing drugs do?
Decrease absorption of Vitamin B12, iron, and B1
What interaction does metformin have?
Reduced B12 absorption and decreased terminal ileum absorption.
What interaction do mineral oil, orlistat, bile-acid binding resins have?
Inhibit fat soluble vitamin absorption (A, D, E, and K)
What interaction can antibiotic therapy have?
Reduction of intestinal vitamin K producing bacteria
For a type III reaction what does vitamin K interact with?
Warfarin
What is a large dose of fish oil’s type III reaction?
Increase the effect of warfarin
What is St. John’s Wart’s type III reaction?
Toxicity potential with SSRI medications
What is folic acid’s type III interaction?
Decreases serum concentration of phenytoin, phenobarbital, and primidone.
What happens when taking MAOI drugs and you eat tyramine-containing foods?
A risk for really high BP
What are some tyramine-containing foods?
Fermented or aged food Soy sauce Avocados Anchovies Liver Smoked or pickled fish Cheeses
What are some MAOI drugs?
Linezolid Phenelzine Selegiline Isocarboxazid Tranylcypromine
What type III reaction can high protein foods cause?
Decrease levodopa effectiveness and increase calcium excretion
What is Pyridoxine’s (B6) type III interaction?
Decreases levodopa’s effectiveness b/c it promotes metabolism before levodopa can cross the BBB.
What can sodium rich foods cause?
Increased lithium excretion
What can a low sodium diet cause?
Potential for lithium toxicity
What can potassium rich foods cause?
Increases potential K+ toxicity with K-sparing diuretics (spironolactone), ACE inhibitors, ARB’s, calcineurin inhibitors.
What can long-term use of phenytoin and other anticonvulsants do?
Interfere with Vitamin D and Calcium metabolism
What can corticosteroids cause?
Vitamin B6, A, C, and D deficiencies
What can PI’s (protease inhibitor drugs)/efavirenz cause?
Vitamin D deficiency altered metabolism
PI’s prevent renal hydroxylation of Vitamin D
Based off previous questions what are drugs that can lead to a Vitamin D deficiency?
Phenytoin, corticosteroids, PI’s, and efavirenz.
What interaction can Isoniazid cause?
Inhibits pyridoxine (B6) conversion to its active form
What interaction does methotrexate cause?
Methotrexate inhibits conversion of folic acid to its active form.
You supplement folic acid in low doses in RA and Psoriasis.
What interaction can loop diuretics cause during chronic therapy?
Low thiamine (B1)
What interaction can ethanol cause?
Folic acid, B1, B12, and magnesium deficiencies.
It can decrease the production of B6
It can impair Vitamin A, which can lead to night blindness.
What are some drug classes that can cause metabolic alterations?
Steroids (can cause hyperlipidemia, hyperglycemia)
Antireteroviral therapy (HIV drugs)
Calcineurin inhibitors (transplant drugs-that can affect CYP34A)
What are some medications that can alter protein metabolism?
Anabolic hormones-Protein synthesis
Corticosteroids-Muscle wasting
Alcohol-reduced protein absorption and increased nitrogen excretion
What are some medications that can alter metabolism and cause hyperglycemia?
Corticosteroids, calcineurin inhibitors, HIV medications, phenytoin
What are the most notable medications that can cause hypoglycemia?
Insulin
Sulfonylureas
How can inhaled corticosteroids lead to an alteration of taste?
Inhaled corticosteroids can cause oral candidiasis.
What is an osmotic laxative that is commonly used?
Sorbitol-it has alcohol dissolving properties and can improve stability.
10-15g/day=GI discomfort
>15g/day=Laxative
Does and increase in osmolality lead to decreased or increased GI irritations?
Increased.
You want to dilute all hyperosmolar products, if possible.
What can severe malnutrition lead to?
Altered immune function
Decreased drug metabolism
Depleted visceral proteins (increased free drug due to low albumin)
What is there a high risk of in malnourished patients when we refeed?
Over-aggressive repletion (over eating) of macronutrients
What are some metabolic complications when refeeding malnourished patients?
Intracellular mineral movement (hypophosphatemia most common)
Refeeding edema
Vitamin deficiencies
What are some potential nutrient related complications with bariatric surgery?
Reduced exposure to acidic environment and loss of absorptive capacity.
What are some potential macronutrient deficiencies with bariatric surgery?
Calorie deficit
Protein deficit
