Biochemistry: Drug-Nutrient Interactions (Dni's)

Front 1

What are the types of interactions between drugs and nutrients?

Back 1

Medications affect food intake (eg, appetite)

1. absorption
2. metabolism
3. excretion

(food IN meds)

Front 2

Meds for obesity suppress what?

Back 2

Appetite

Front 3

Besides meds for obesity what kinds of med may affect appetite?

Back 3

1. Amphetamines suppress appetite

2. Some anti-depressants lead to wt gain

Front 4

Sedatives often lead to what?

Back 4

Decreased intake of food

Front 5

Any med that causes ? or ? may decrease food intake.

Back 5

Nausea or indigestion

Front 6

Foods affect the absorption of ?.

Back 6

Meds

Front 7

Give an example of why it is important not to generalize about food affecting the absorption of meds?

Back 7

For example, food reduces the absorption of captopril, but it improves the absorption of hydralizine, both of which are hypertensives. Recommendations: take captopril on an empty stomach, but hydralazine with food.

Front 8

Give an example of a trade-off concerning meds and absorption?

Back 8

Aspirin is best absorbed on an empty stomach but it may lead to nausea.

Front 9

What foods substances reduce absorption?

Back 9

Food substances that bind meds.

Front 10

Give 4 examples of food substances that may bind meds and reduce their absorption?

Back 10

1. Minerals (in foods and antacids)

2. Fiber

3. Phytates (husk of grains, legumes, and seeds)

4. Oxalates (eg, rhubarb, spinach, beets, nuts, chocolate, tea, wheat bran, strawberries)

Front 11

Not only does food sometimes affect the absorption of meds but meds may also affect the absorption of food. How do laxatives do this?

Back 11

They reduce the time in the intestine, and therefore reduce absorption. Mineral oil may reduce ADEK. Regular use may lead to dependence.

Front 12

How might enzyme replacements affect absorption?

Back 12

They may increase absorption (eg, lactase)

Front 13

Give an example of a mutual interaction?

Back 13

Tetracycline and calcium (or iron) adversely affects each other's absorption (leading to excretion of both).

Recommendation: Take Tet on an empty stomach (1hr to 2hrs after meals, including milk, milk products, antacids with calcium, mineral supplements)

Front 14

Give an example of foods affecting drug metabolism?

Back 14

Vitamin K (clotting factor) intake affects appropriate dosing of warfarin (coumadin, an anti-coagulant), which affects blood clotting. So a prescribed dose of warfarin depends upon vitamin K intake, and so may need to be adjusted if food intake changes significantly (eg, if more lettuce and greens are eaten in the summer)

Front 15

What is a generalization made about herbs and supplements and their relationship to coumadin?

Back 15

They can (in some cases) reduce or (in others) increase the effectiveness of coumadin.

Front 16

Because of the effects herbs and supplements have on coumadin what has to be done with their use?

Back 16

The use of these must be either avoided or consistent.

Front 17

List 6 herbs?

Back 17

1. garlic

2. ginger

3. ginkgo

4. St. john's wort

5. echinacea

6. feverfew

Front 18

Name 3 supplements?

Back 18

1. Coenzyme Q

2. Omega-3 FAs

3. Vitamin E

Front 19

Nutrients are ? in order for some meds to be ?.

Back 19

They are reqd in order for some meds to be effective.

Front 20

Give an example of a nutrient that is required for a med to be effective.

Back 20

Fosamax (alendronate), for the tx of osteoporosis, reqs Vit D and calcium.

Front 21

What does grapefruit juice do to metabolism?

Back 21

It inhibits intestinal CYP3A4 enzymes (part of the cytochrome P450 system), which plays an important roles in the elimination of many drugs.

This affects AUC,Cmax, and half-life, generally increasing plasma concentration.

The effect is seen with whole grapefruit, juice, and concentrate, though the extent is variable.

Front 22

Caffeine is a what?

Back 22

CNS stimulant

Front 23

How does caffeine affect the metabolism of meds?

Back 23

It potentiates actions of CNS-stimulant meds (eg, amphetamines)

It limits the effectiveness of depressants (eg, barbituates)

Front 24

How might licorice affect the metabolism of meds?

Back 24

(natural licorice, not the artificial stuff in some candy/breath fresheners) Promotes Na+ retention and K+ excretion. May interfere with diuretics and antihypertensives.

Front 25

How might corticosteroids affect the metabolism of food?

Back 25

They are anti-inflammatory and immunosuppressive. They interfere with the met. of calcium and vit D, leading to a loss of Ca++ from bones. This increases the risk of osteoporosis.

Front 26

Anyone on long term steroid therapy should consider taking what?

Back 26

Vit D supplements and possibly Ca++

Front 27

How does methotrexate affect the metabolism of food?

Back 27

It is structurally similar to, and may interfere with metabolism of, folate. This is usually not a problem when used at low doses for the tx of arthritis, lupus, psoriasis, asthma, or inflammatory bowel disease. However, it is used at higher concentrations in the tx of cancer, and at these levels it may interfere with the action of folate. So folate supplementation may be appropriate.

Front 28

How might aspirin affect the metabolism of food?

Back 28

It competes with folate for its protein carrier, and so may limit the bioavailability of folate. This is only a problem when aspirin is taken regularly. (eg, 650mg q 4hrs for several days)

Front 29

How is tyramine involved in metabolism?

Back 29

It is an AA found in many foods.

It stimulates the release of norepinephrine which may cause severe headaches, and may cause HTN.

It can be, and usually is, inactivated.

Monoamine Oxidase Inhibitors (MAOIs) which are used to tx some forms of severe depression, block this inactivation pathway.

So anyone taking MAOIs must restrict their tyramine intake.

Front 30

How might Vit C (nutrient) affect excretion of meds?

Back 30

It increases the acidity of the urine, which decreases the excretion of aspirin, which increases the plasma conc of aspirin.

Front 31

How might sodium (a nutrient) affect the excretion of meds?

Back 31

It decreases the lithium (used to tx psychiatric disorders), raising the plasma conc. of lithium.

So it is important to keep the sodium intake constant so to keep the Li conc constant.

Front 32

How might diuretic meds affect nutrient excretion?

Back 32

They increase the excretion of calcium, potassium, magnesium, and zinc.

Front 33

How might amphotericin-B affect the excretion of nutrients?

Back 33

It is an anti-fungal agent that increases the excretion of potassium and magnesium.

Front 34

List 6 possible ingredients in meds that may be a cause for concern.

Back 34

1. Sugar (diabetics)

2. Lactose (Lactose intol)

3. Aspartame (PKU)

4. Sorbitol (diarrhea)

5. Sodium (salt-sensitivity)

6. Caffeine (diuretic)

(small amts may not be a problem but you need to watch total intake)