Food and drug interactions

Question 1

what is biotransformation and where does it occur?

Answer 1

Is the way the drug get metabolized, the
major organ is the liver
the metabolism of a drug by reaction such a s oxidation, reduction, hydrolysis or conjugation

Question 2

what is Pharmacokinetic

Answer 2

: movement of a drug through
the body by absorption, distribution, metabolism,
and excretion
study of the physiologic and biochemical effects of a drug or combination of drugs

Question 3

What is Pharmacodynamics:

Answer 3

study of physiologic and
biochemical effects of a drug or combination of
drugs

Question 4

cytochrome p-450

Answer 4

Cytochome p.450 enzyme system is responsible for the oxidative metabolism of many
orally administered drugs. The increase of unmetabolized drugs result in a greater
pharmacologic effect and possible toxicity.

Question 5

Grapefruit juice drug increase interaction

Answer 5

Grapefruit increases bioavailability of
drugs by inhibiting the cytochrome p-450 Pomelos, tangelos, Seville oranges can cause
the same effect as grapefruit.

Question 6

low tyramine diet

Answer 6

Slow inactivation of phenelzine, a monoamine oxidase(MAO) inhibitor, increases the risk for hypertensive crisis if foods high in tyramine are consumed
Aged foods, anything fermented, meats stored longer than 3 days, banana peel
caution - pizza, coffee, wine,

Question 7

Drugs that decrease appetite

Answer 7

ampetamines, cns stimulants(adderall, ritalin, dexedrine, meridia)

Question 8

Drugs that increase appetite

Answer 8

antipsychotics(clozapine, olanazpine) antidepressants,(amitriyline) anticonvulsants,

Question 9

Danger of antibiotics

Answer 9

they cause diarrhea

Question 10

What mineral is affected when a person has a decrease taste sensation (hypogeusia)

Answer 10

zinc

Question 11

What happens when a person is hypoalbuminic (< 3.0mg/dl) and taking medications
that are highly bound?

Answer 11

Patients with albu- min levels below 3 g/dl arc at increased risk for adverseef- fects from highly protein-bound drugs. Usual adult dosesof highly protein-bound drugs in such persons may produce more pronounced pharmacologic effectsthan the samedose in personswith normal semm albumin levels.A lower dose of such drugs is often recommended for patients with low albumin levels

Question 12

proper feeding tube methods

Answer 12

Most compatibility studies of medication and enteral products have focused on the effect of the drug on the in- tegrity of the enteral product. More important is the effect of the enteral product on tlre bioavailability of the drug. This area requires much more research as the placement of feeding tubes becomes a more common practice. Bioavail- ability problems are common with phenytoin (Dilantin) and tube feeding. Becauseblood levels of phenltoin are rou- tinely performed to monitor the drug, much information existsabout the reduction of phenytoin bioavailability when given with enteral feedings, and individual variability is sig- n i f i c a n t . R e c o m m e n d a t i o n s t o s e p a r a t e p h e n y t o i n s u s p e nsion from tube-feeding formulas are common. Stopping the tube feeding before and after the phenytoin dose is gener- ally suggested,but recommendations vary from 1- to 4-hour intervals. The most common is a 2-hour feeding-free inter- val before and after the dose of phenytoin is administered

Question 13

Cathartic/laxatives

Answer 13

Drugs can reduce nuuient absorption by influencing the transit time of food and nutrients in the gut. Cathartic agents and laxatives reduce transit time and may causediar- rhea, leading to lossesof calcium and potassium. Diarrhea may be induced by drugs containing sorbitol or by drugs

Question 14

antacids

Answer 14

Gastrointestinal pH is an important factor for the ab- sorption of somedrugs.Any situationsresulting in changes in gastric acid pH, such as achlorhydria or hypochlorhy- dria, may reduce drug absorption

Question 15

diuterics/loop diuretics

Answer 15

The action of diuretics and antihypertensivedrugs may be antagonized.The resultant hypokalemia may alter the action of some drugs
Drugs can increase the excretion of a nutrient by interfering with nutrient resorption by the kid- neys. For instance, most clinicians know that loop diuretics such as furosemide (Lasix) or bumetanide (Bumex) increase the excretion of potassium; but these diuretics also increase the excretionof magnesium,sodium, chloride, and calcium. Potassium supplements are routinely prescribed with loop diuretics. In addition, clinicians need to consider supple- ments of magnesium and calcium, especiallywith long-term drug use,high dosesof the diuretics,or poor dietary intake. Electrollte and magnesium blood levels should be moni- tored. Prolonged useofhigh-dose diuretics,particularly by older patients on low-sodium diets, can causesodium deple- tion.
Licorice

Question 16

Lithium

Answer 16

Food and nutrients can alter the resorption of drugs from the renaltubule.Resorptionof the antimanicagent lithium (Lithobid or Eskalith)is closely associated with the resorp- tion of sodium.When sodium intakeis low or when a pa- tient is dehydrated,the kidneys resorb more sodium.In the person treated with lithium, the kidney resorbs lithium as well as sodium under these conditions.Hisher lithium lev- els and possibletoxicity result. When exciss sodium is in-gested,the kidneys eliminate more sodium in the urine and likewise more lithium. This produces lower lithium levels and possible therapeutic failure.

Question 17

coumadin

Answer 17

Warfarin (Coumadin) is an oral anticoagulant that re- ducesthe hepatic production of four vitamin K-dependent clotting factors by inhibiting the conversion of vitamin K to a usable form. Becausethis is a competitive interaction, the ingestion of vitamin K in the usableform will oppose the action of warfarin and allow the production of more clotting factors. To achieve an optimal level of anticoagu- lation, a balance must be maintained between the dose of the drug and the ingestion of vitamin K. Counseling of a person taking oral anticoagulation therapy should include medical nutrition therapy (MNT) to maintain a consistent dietary vitamin K intake rather than prohibiting all high-vitamin K foods, such as dark green leafr vegetables (|ohnson, 2005) (see Appendix 50). Coenzyme Q10, St. John’s wort or avocado also counteract the effect of warfa- rin. Ingestion of other substancesmay enhancethe antico- agulant effect of warfarin. These substancesinclude on- ions, garlic, quinine, papaya, mango, or vitamin E supplementsin dosesgreater than 400 IU. Certain herbal
products such as dong quai, which contain coumarin-like substances,or ginseng, which is a platelet inhibitor, also enhance the effect of the warfarin. Enhancement of the anticoagulation effects of warfarin may lead to serious bleeding events

Question 18

cholestyramine

Answer 18

may cause iron deficiency anemia

Question 19

antibiotic - tetracycline

Answer 19

The antibiotics ciprofloxacin (Cipro) and tetracycline (Achromycin-V or Sumycin) form insoluble complexes with calcium in dairy products or calcium-fortified foods and beverages;calcium, magnesium, zinc, or iron supple- ments; or aluminum in antacids, thus preventing or reduc- ing the absorption of both drug and nutrient (Neuhofel et a1.,2002).The optimal approach to avoid this interaction is to stop noncritical supplements for the duration of the antibiotic prescription. If this is not possible,particularly with magnesium or with long-term antibiotic use, it is advisable to give the drug at least 2 hours before or 6 hours after the mineral.

Question 20

hypertensive agents

Answer 20

A major side effect of stimulant drugs is hypertension. Thus they are often contraindicated for hypertensive pa- tients or those who have seizures or cardiac disease Because hypertension is common among obese persons,these contraindications may limit the use of stimulants in obese or overweight hypertensive patients.

Question 21

antidepresssants

Answer 21

Zyprexa), tricyclic antidepressant drugs such as arnitriptyline @lavil), and the anticonvulsant dival- proex (Depakote) often lead to weight gain. Patients complain of a ravenousappetite and the inability to “feel fuII.

Question 22

methrotrexate

Answer 22

Methotrexate (MTX or Rheumatrex) is a folic acid an- tagonist used to treat cancer and rheumatoid arthritis. Without folic acid, DNA synthesisis inhibited, cell replica- tion stops, and the cell dies. Pyimethamine (Daraprim), usedto treatmalariaandoculartoxoplasmosis,isalsoafolic acid antagonist. These drugs bind to and inhibit the en4.nne dihydrofolate reductase, preventing conversion of folate to its active form (seeChapter 3), which eventually can lead to megaloblastic anemia as a result of folate deficiency (see Chapter 31). Leucovorin (folinic acid, the reduced form of folic acid) is used with folic acid antagonists to prevent ane- mia and gastrointestinal damage, especially with chemo- therapy such as high-dose methotrexate. Leucovorin does not require reduction by dihydrofolate reductase; thus, un- like folic acid, it is not affected by folic acid antagonists. Therefore leucovorin may “rescue” normal cells from MTX damage by competing for the same transport mechanisms into the cells. Howeveq for patients with rheumatoid arthri- tis who are receiving low-dose MTX therapy, studies show that administration of daily folic acid supplements or folinic acid can lower toxicity without affecring effr,cacyof the drug

Question 23

corticosteriods

Answer 23

Corticosteroids such as prednisone decreasesodium ex- cretion, resulting in sodium and water retention. Con- verselll enhanced excretion of potassium and calcium is causedby these drugs; so a low-sodium, high-potassium diet is recommended. Calcium and vitamin D supplements are generally recommended with long-term cortiiosteroid use to prevent osteoporosis,suchasmight bethe casefor aper- son with asthma, lupus, or rheumatoid arthritis. With corticosteroid use this risk is important becauseit appears that not only is calcium lost in the urine, but corticosteroids may impair intestinal calcium absorption and the bone- building activity of osteoblasts

Question 24

hypoglycemic agents

Answer 24

Ethanol can inhibit gluconeogenesis, particularly when consumed in a fasting state. Inhibition of gluconeogenesis will prolong a hypoglycemic episode causedby insulin or an oral hypoglycemic agent such as glyburide

Question 25

what foods decrease the absorbtion of iron and what percent and stuff

Answer 25

The absorption of the iron from supplements may be decreasedby 50o/”when taken with food. Iron is best ab- sorbed when taken with 8 oz of water on an empty stomach. If iron must be taken with food to avoid sastrointestinal distress,it should not be taken with bran, eggi, high-phyate foods, fiber supplements,tea, coffee, dairy products, or cal- cium supplements,becauseeachof thesecandecreaseiron absorption