FOOOOOOD and DRUG interactions

Question 0

Examples of Binding of drugs by food

Answer 0

divalent cations in diary can be chelated by certain drugs, rendering them ineffective
high fat meals can increase solubility of lipophilic drugs
high fiber diets can decrease water soluble drug absorption

Question 1

What can alter normal function of GI tract can affect absorption of drugs

Answer 1

changes in transit time (slower or faster) will affect absorption rate
electrolyte imbalances may affect how drug is transported into cells of the gut
changes in gut pH can alter drug solubility, or can alter the chemistry of the drug

Question 2

Worst case scenario meal

Answer 2

High calorie (800-1000) 
High fat ~50% of calories are from fat

Question 3

Drug uptake/efflux in enteric cells are mediated by

Answer 3

OATP

P-gp

Question 4

First pass drug metabolism in enteric cells is mediated by

Answer 4

SULT
Esterase
CYP3A

Question 5

SULT

Answer 5

modify xenobiotics and hormones by adding sulfur gropus
inhibited by foods high in flavanoids - fruit juice, tea - prevents normal catecholamine deactivation = blood pressure changes, migrane headaches, atrial fibrillation

Question 6

Esterase

Answer 6

many drugs require cleavage of an ester group to become active
inhibition of esterase results in ester group being stabilized, results in a build up of pro-drug
resutls in much more of drug being passed into the plasma, where rapid hydrolysis by plasma proteins will give you sudden burst of active drug

Question 7

CYP450

Answer 7

oxigenases
donate electrons from NADPH to O2 and the substrate
many diff types
rich in the liver, where it is involved in breakdown of drugs (deactivation)
Intestinal CYPs involved with first pass metabolism
CYP3A predominant form in enterocytes and responsible for oxidative metabolism of over half of drugs on market

Question 8

Inhibition of CYP will

Answer 8

lead to enhanced systemic drug exposure

can be lethal

Question 9

Antioxidants and furanocoumarins are major inhibitors of

Answer 9

CYP3A

found in Tea, coffee, red wine, beer, fruit juices (tomato, bitter orange, Grapefruit juice)

Question 10

Grapefruit juice

Answer 10

high in furanocoumarins

also has components shown to inhibit other enterocyte proteins G-pg (meant P-gp?), OATP, esterase, SULT - flavanoids

Question 11

Number of known interactions with Grapefruit juice

Answer 11

over 85 different drugs
43 of which are listed as severe
one of the more severe side effects is rare ventricular tachycardia (torsade de points)

Question 12

Drugs known to interact with GFJ

Answer 12

statins
calcium channel blockers
meds that treat - anxiety, heart arrhythmia, depression, seizures, malaria and insomnia

Question 13

Do not eat/drink what when taking antibiotics?

Answer 13

Milk/dairy
these will chelate divalent cations, such as Ca+2, Mg+2
they will bind up and block drug absorption
ex: tetracyclines, fluoroquinolones (cipro)
food ex: dairy (calcium), antacids (calcium, Mg) supplements (iron, ca, mg)

Question 14

Action of Warfarin

Answer 14

anticoagulant
vit K agonist

blood clotting enzymes require modification by Vit K dep. enzyme to become active - Warfarin interferes with this process and helps to prevent clots

Question 15

Diets high in Vit K can alter

Answer 15

the effectiveness of Warfarin treatments

drug is notoriously difficult to dose correctly - dietary changes can make prescribed dose ineffective

Question 16

Foods high in Vit K

Answer 16

green, leafy vegetables - collards, mustard greens, turnip greens, spinach
Cruciferous foods: kale, brussel sprouts, broccoli

Question 17

MAOIs

Answer 17

monoamine oxidase inhibitors are used to treat depression
foods high in Tyromides have been shown to produce severe hypertensive crisis in pts taking MAOIs
-such a bad problem, that MAOIs are under utilized

Question 18

Cheese Reaction

Answer 18

Tyromide containing foods
Matured cheese, red wine, bananas, yogurt, shrimp paste, salami
mostly in fermented foods

Question 19

Licorice contains

Answer 19

chemical called glycyrrhizin - acts as a potent inhibitor of 11 beta-hydroxyl steroid dehydrogenase
leads to increase in mineralcorticoid receptors, leading to sodium retention and potassium depletion
sometimes found in teas and herbal blends - so warn pts

Question 20

Net effect of Licorice and Antihypertensives

Answer 20

will interfere with antihypertensives and antiarrhythmics
high intake of licorice linked to edema, increased blood pressure, and suppression of renin-angiotensin-aldosterone system

Question 21

Mechanisms that Alcohol can interfere with

Answer 21

broken down in liver so can decrease efficiency of drug break down

• can lead to increase in system drug toxicity
• liver damage can occur
• universal solvent so if taken with drug could enhance solubility

Question 22

Alcohol is amphipathic so

Answer 22

it can increase the solubility of both lipophilic and hydrophilic drugs, increasing bioavailability

Question 23

What does Alcohol irritate?

Answer 23

stomach lining
can increase absorption of drug
if paired with a drug which is also an irritant (NSAIDs) an damage stomach lining

Question 24

Bronchodilator

Answer 24

have stimulating effects on CNS

ex: theophylline, albuterol, epinephrine

Question 25

Bronchodilators and Caffeine

Answer 25

both xanthine/xanthine derivatives
have similar effects, taking together could amplify effects leading to nausea, vomiting, irritability, increased heart rates
puts pts at increased risk of drug toxicity

Question 26

Bronchodilators and caffeine: Foods to avoid

Answer 26

chocolate
Tea
coffee