This document discusses drug-nutrition interactions and is from the Department of Medical Systems Pharmacology at Rome University. It describes two types of interactions: 1) how drugs can impact nutrient absorption, metabolism, distribution and elimination and 2) how single or multiple nutrients/foods can alter drug therapeutic response. Specific examples are provided such as how PPIs can reduce vitamin B12 absorption. Grapefruit juice is discussed as an inhibitor of intestinal CYP3A4 enzymes and certain transporters, increasing drug concentrations of calcium channel blockers, benzodiazepines and statins. Health professionals should consider patients' diets and use of supplements/herbs when prescribing medications due to potential interaction risks.

1. UTV Roma, Dip. MEDICINA DEI SISTEMI, Farmacologia.

2. UTV Roma, Dip. MEDICINA DEI SISTEMI, Farmacologia.

3. Drug and nutrition interactions can
be classified in two distinct groups:

DRUG-NUTRITION STATUS INTERACTIONS.
Drugs can compromise the absorption,
metabolism, distribution and elimination of
nutrients or nutritional intake;

FOOD –DRUG INTERACTIONS.
Single or multiple nutrients or food can alter
therapeutic drug response
UTV Roma, Dip. MEDICINA DEI SISTEMI, Farmacologia.

4. Drug-nutrition status interactions
Nutritional deficiencies
Changes in appetite
and body weight

5. Drug-nutrition status interactions (nutrient deficiencies)
Drug
micronutrient
Effect
PPI
Vitamin B12
absorption
Vitamin C
absorption
Iron
absorption
Risk factor
Sustitution scheme
Age, hypochlorydria, atrophic
gastritis , HP infection, CYP 2C19
inhibition
HP infection, atrophic gastritis ,
hypochlorydria
Vegetarians, vegans,
hypochlorydria, iron deficiency,
elders masticatory problems
1mg of IM weekly or
2mg/d per os
500mg/d
Weight [Kg]xtarget
Hb-measured
Hb[g/L]x0,24+500mg
Metformin
Vitamin B12
absorption
Vegetarians, vegans
1mg of IM weekly or
2mg/d per os
Antiepileptic
(valproic acid)
Vitamin D
Carnitine
metabolism
absorption
Age, vit D deficiency
2000-4000 IU/d
Diuretics,
glucocorticoids
Potassium
elimination
Hypokalemia
3600mg/d
Cholestyramine,
orlistat
Vitamins
(A,E,D,K)
absorption
Vitamin deficiency
ACE I, ARA II
Zinc
Cell availability
renal elimin
Age, diabetes, heart failure
25mg/d for6 Mo
Statin
CoQ10
Cell availability
Endogenous
production
Age, sport activity
100-200mg/d
Anticholinergic,
opiates
Many
nutrients
absorption

6. Statin and CoQ10 deficiency
UTV Roma, Dip. MEDICINA DEI SISTEMI, Farmacologia.

7. Changes in appetite
and body weight
Antipsychotic drugs associated with weight gain
Chlorpromazine
Quetiapine
Olanzapine
Clozapine
Risperidone
Weight gain have
been associated with
the use of second
generation antipsycotic
weight gain

8. FOOD –DRUG INTERACTIONS
Food
Drugs
Proposed Mechanism Clinical Outcome
Vitamin K rich food
(broccoli, , spinach,
asparagus, brussels
sprouts)
Warfarin
Vitamin K increases the
syntesis of clotting factors,
reducing the efficacy of
warfarin
Risk of treatment failure
Tyramine containing food
(Aged cheese, red wine,
salami, sausage, shrimp
paste, sauerkraut).
MAO inhibitors
Inhibition of degradation
of tyramine found in
foods
Hypertensive crisis
Bananas, spinach,
potassium supplements
Spironolactone
Increase of potassium
secondary to synergistic
effect
Risk of hyperkalemia
Dairy products (milk,
cheese, yogurt, icecream)
Tetracyclines
Ciprofloxacin
Bisphosphonates
Chelation of drugs by
calcium ions
Risk of treatment failure
Grapefruit juice
Calcium-channel
blockers (felodipina),
benzodiazepines
(triazolam), statins
(atorvastatin,
lovastatin, simvastatin)
immunosoppressant
(cyclosporine)
Antihistaminies
(fexofenadine)
Inhibion of intestinal
CYP3A4 enzyme and
OATP2B1, OATP1A2
transporters
Toxicity or possible
treatment failure

9. 200 ml double-strength
grapefruit juice 3 times
daily for 2 days
UTV Roma, Dip. MEDICINA DEI SISTEMI, Farmacologia.

10. Felodipine concentration
Triazolam concentration
Time (h)
Time (h)
UTV Roma, Dip. MEDICINA DEI SISTEMI, Farmacologia.

11. FLAVONOIDS:
NARINGENIN
QUERCITIN
NARINGIN
FURANOCUMARINS:
BERGAMOTTIN
PARADISIN
BERGAPTOL
6’,7’-DIHYDROXYBERGAMOTTIN
UTV Roma, Dip. MEDICINA DEI SISTEMI, Farmacologia.

12. GFJ (bergamottin)
UTV Roma, Dip. MEDICINA DEI SISTEMI, Farmacologia.

13. UTV Roma, Dip. MEDICINA DEI SISTEMI, Farmacologia.

14. GFJ (narigin)
Fexofenadine
aliskiren
Celiprolol
UTV Roma, Dip. MEDICINA DEI SISTEMI, Farmacologia.

15. Il personale sanitario
(medico, infermiere, dietista, nutrizionista)
1- deve tener conto delle abitudini alimentari del paziente
2- deve sempre chiedere se il paziente stia assumendo
integratori, erbe medicinali per qualunque scopo e sotto
qualunque forma
3- deve conoscere le interazioni fra farmaci e
alimenti/integratori/erbe

16. http://www.druginteractioncenter.org
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Grapefruit Juice Drug categories
Following is a list of drug categories that contain some drugs that might negatively interact with
Grapefruit Juice. Grapefruit Juice does not need to be avoided with all drugs in this category.
Antiallergics
Antiarrhythmics
Antibiotics
Anticoagulants
Antimalaria drugs
Antiparasitic drugs
Antitumor drugs
Anxiolytics
beta-blocker
Calcium channel blocker
HIV protesase inhibitors
HMG-CoA reductase inhibitors (statins)
Hormones
Immunosupressants
Other drugs
Over-the-counter (OTC)drugs
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Site created by I. Zdrojewski, J. Meyer, W. de Castro
Data maintained by Chethan Sampath; Code maintained by Ned Phillips
Last modified Thu Oct 3 2013