Ch 18: Drug-Nutrient Interactions

Question 1

What should be the first choice when carbamazepine?

Answer 1

Adequate dilution of the suspension (or slurry from a crushed tab) prior to administration and adequate flushing after the dose. Carbamazepine is an acid stable drug.

Question 2

What is the minimum recommended flush for enteral feeding tubes when administering medications?

Answer 2

The minimum recommended volume for flushing enteral feeding tubes is 15 mL, although larger volumes are often used

Question 3

Which kind of medications should not be crushed/dissolved and flushed down a feeding tube?

Answer 3

Forms such as long acting, sustained release, slow release or delayed release forms containing several doses in 1 tab/capsule. Enteric coated products should also not be crushed.

Question 4

What variables increase the risk of physical interaction?

Answer 4

pH at which drug and PN or EN formula is most stable, presence of cations/anions known to react chemically, concentration and chemical complexity of nutrients, and time/temp/duration of exposure to one another

Question 5

Which products avoid first pass metabolism in the liver?

Answer 5

Rectal and sublingual products

Question 6

Feeding/drug delivery into the ______ allow most of the normal physiological functions associated w/ digestion to be utilized

Answer 6

Stomach

Question 7

What components of EN may cause DNI?

Answer 7

Complex protein and fibers; nutrients that alter gastric emptying and GI motility can later rate/extent of drug absorption thereby contributing to DNIs in the clinical setting

Question 8

Administration to the _____negates the need for enteric coating

Answer 8

jejunum; this is where the coating is designed to dissolve; therefore, dissolving the coating in a bicarb solution than crushing the tab is acceptable for jejunal administration

Question 9

What type of DNI typically results in occlusion of feeding tube; other outcomes include reduced bio-availability of drug/nutrients?

Answer 9

Physical interaction

Question 10

Which macronutrient is frequently associated with chemical reactions in EN/PN formulas?

Answer 10

Amino Acids

Question 11

In PN, what is influenced by pH?

Answer 11

Both physical compatibility and chemical stability

Question 12

Increasing time of exposure between PN and drug ____ risk of interactions.

Answer 12

increases risk of interactions; therefore, admixture of a drug into PN formulation poses greater risk of interaction than co-infusion

Question 13

What is the policy many facilities follow when administering cipro/norfloacin

Answer 13

Many facilities follow a policy of holding administration of EN formula for at least 1 hour before and 2 hours after a fluoroquinolone dose with cipro or norfloxacin; however, holding feedings w/ other fluoroquinolones should not be done routinely

Question 14

How long should TF be held with phenytoin?

Answer 14

holding administration of EN formula for at least 1 hour (possibly 2) before and after phenytoin administration seems to produce most consistent results

Question 15

Consistent intake of EN formula containing less than _____ of vit K per 1000 kcal is not expected to cause warfarin resistance

Answer 15

100 mcg

Question 16

____ inhibits the isoenzyme CYP3A4, thereby increasing serum levels of drugs normally metabolized by this isoenzyme

Answer 16

Grapefruit juice

Question 17

Hoes EN affect warfarin bio-availability?

Answer 17

TF should not affect bioavailability of warfarin, and TF should not be held to mitigate warfarin EN interaction though no definitive recommends are provided at this time

Question 18

At what pH are most PN fomulas at, and how does this affect drug administration?

Answer 18

Most PN formulas have a slightly acidic pH (5-6.5), drugs requiring a high pH or low pH for beset solubility are typically incompatible with PN

Question 19

Which medications may cause taste alterations for a patient?

Answer 19

Colace, Cisplatin, Flaygl, Dilantin