drug interactions with tube feeds

Question 1

IV:PO conversion levothyroxine

Answer 1

3:4

Question 2

IV:PO conversion ciprofloxacin

Answer 2

1:1.25

Question 3

IV:PO conversion furosemide

Answer 3

1:2

Question 4

phenytoin

Answer 4

co-administration results in decreased absorption and subtherapeutic levels. if possible, give IV.

stop tube feed 2 hours before administration

Question 5

acetaminophen

Answer 5

may contain sorbitol resulting in GI effects, switch to an equivalent agent

Question 6

carbamazepine

Answer 6

decreased absorption and adheres to feeding tube, dilute with SWFI or NS and monitor serum concentration

Question 7

warfarin

Answer 7

decreased absorption and effect, depends on vitamin K component of feed. monitor INR and adjust dose or substitute with LMWH

Question 8

sucralfate

Answer 8

can bind to the feed= reduced effect and GI obstruction

stop feed 1 hour before and 1 hour after

Question 9

PPIs

Answer 9

complicated by acid-labile medication, may become sticky and occlude small-bore tubes

co-administer with acidic liquid, prepare as an oral suspension, or give IV

Question 10

levothyroxine

Answer 10

decreased absorption and efficacy

stop feed 1 hour before and 1 hour after, monitor serum concentration

Question 11

antacids

Answer 11

tube placement may impact ability of drug if unable to neutralize stomach acid

Question 12

tetracyclines and fluoroquinolones

Answer 12

reduced bioavailability from complexation of drug with divalent and trivalent cations in tube feed

hold tube feed for one hour before, after

avoid jejunal administration of ciprofloxacin

Question 13

disadvantage to liquid solution

Answer 13

excipients can cause diarrhea, multiple bottles, hyperosmolar=GI effects, bioavailability can differ between liquid and tablet

Question 14

disadvantage to liquid suspension

Answer 14

need to shake adequately to get accurate dosing, large granule can block tube, expensive

Question 15

disadvantages to soluble tablets

Answer 15

some drugs can take time to dissolve

Question 16

disadvantages to effervescent tablets

Answer 16

sodium content can be high, may require large volume of water, some drugs can take time to disperse

Question 17

disadvantages to opening capsules

Answer 17

may not disperse in water, occupational exposure, can be difficult to open, PK differences