Some Food Drug Interactions needed for junior doctors to know. Includes interaction effect and solutions.

1. FoodDrug
Interactions
Dr. Ebrahim M. Ebrahim

2. Outlines:
 Introductory Case Scenario.
 Definitions, Pharmacokinetics, and
pharmacodynamics.
 Common foods and their interactions with
various drugs.

3. A 58-year -old woman has a history of major depressive disorder that has been in remission
for the past ten years. She takes phenelzine daily and sees her psychiatrist every other
month. While on vacation, the patient and her husband indulge in a gourmet meal.
Afterward, the patient becomes concerned as she believes one of the dishes may have
contained aged cheese, which her psychiatrist had warned her about eating. She comes to
the emergency department of the local hospital to express her concerns. Which of the
following is most appropriate to monitor?
A. Temperature.
B. BUN and Creatinine.
C. Blood Pressure.
D. Liver Function Tests.
E. Creatine Phosphokinase.
Case Scenario

4. Answer is C. Monitor her Blood Pressure.
Phenelzine is a monoamine oxidase inhibitor (MAOI). The MAOis are an older
class of antidepressant drugs mostly used in the treatment of refractory
depression. MAOis are typically not used as first-line therapy in part because of
the dietary restrictions associated with their use. If a patient taking an MAOI
consumes foods high in tyramine, including aged meats and cheeses,
hypertensive crisis can result.

5. Introduction & Definitions:
A food – drug interaction
occurs when a food, or one of
its components, interferes with
the effects of a drug in the
body.
The content of certain foods
interact with some drugs and
produce alterations in the
pharmacokinetics and

6. Introduction & Definitions:
Pharmacokinetics: is what the
body does to the drug from
absorption through distribution

7. Introduction & Definitions:
Adverse food-drug interaction
 Prevent the therapeutic effect of
a medicine.
 Exaggerate the therapeutic effect
of a medicine.
 Make a side effect worst.
 Cause a new side effect.

8. Common foods and their interactions with
various drugs:

9. Diary Products:
Mild, Cheese, Butter, Curd, Ice
Cream, etc.
 Common interactions with:
Quionolones, Tetracyclines,
Bisphosphonates, etc
 Results in:
Decreased therapeutic effect DT
reduced absorption.
 Solution:
Ca++ rich diary products and Ca++
supplementations should be taken two hours
before or six hours after the interacting
medication.

10. Tyramine Rich Foods:
Aged Cheese, Wines, etc
 Common interactions with:
Non-Selective MAOI
(Phenelzine Tranylcypromine,etc).
 Results in:
Excessive Sympathetic Activity.
Life-threatening hypertensive
reactions.
 Solution:
Avoid tyramine rich foods when using
MAOI inhibitors.

11. Tyramine:
Normally degraded by
monoamine oxidase (MAO).
Levels •in patients taking MAO
inhibitors
who ingest tyramine-rich foods
(eg, cheese, wine). Excess
tyramine enters presynaptic
vesicles and
displaces other
neurotransmitters (eg, NE) Ž•
active presynaptic
neurotransmitters Ž•diffusion

12. Potassium Rich Foods:
Bananas, Avocado, Dried
Fruits,
Sweet potatos, etc
 Common interactions with:
ACEi, ARBs, K+ Sparing Diuretics.
(Lisinopril, Losartan,
Spirinolactone,etc).
 Results in:
Increased Risk of Hyperkalemia.
 Solution:
Avoid low sodium foods and salt
substitutes should be avoided

14. Vitamin K Rich Foods:
Kale, Collards, Spinach, Turnip
greens,
Brussels sprouts and Broccoli,
etc
 Common interactions with:
Warfarin (Vitamin K epoxide reductase
inhibitor, 10,9, 7, 2)
 Results in:
Increased Intake will increase risk of
thrombosis DT.
Reduced Intake will increase risk of
bleeding.

16. Fiber Rich Foods:
Wheats, Corn, Coconut shreds,
Raisins, etc
 Common interactions with:
Digoxin, Amoxicilin, Levothyroxin, TCA
(Doxepin and Desipramine)
 Results in:
Fiber binds the drugs in the gut delaying
and reducing absorption.
 Solution:
Do Not eat much fibers when taking these
medications.

17. Caffeine Drinks:
Coffee, tea, energy drinks, soft
drinks,
etc
 Common interactions with:
Theophylline, Prednisolone, OCPs,
Ciprofloxacin, Cimetidine, etc
 Results in:
Inhibition of Theophylline metabolism with
subsequent adverse effects of it. (Jitteriness,
Insomnia, and Cardiac Arrythmias).
Reduced caffeine metabolism e subsequent
increased effects
of caffeine.

18. Grapefruit Juice:
Grapefruit and its juice.
 Common interactions with:
Statins (increased risk of rhabdomyolysis), erythromycin,
domperidone, amiodarone (increased risk for QT prolongation) ,
CCB (inhibit its metabolism, increased risk of hypotension, headache,
flushing, edema) , OCPs, (inhibits its metabolsim increasing risk
of DVT), immunosuppressants (cyclosporine, Tacrolimus,, inhibiting its
metabolism with increased risk of nephrotoxity), opioids (fentanyl,
ketamine, oxycodone, inhibiting their metabolism with increased risk of
respiratory depression).
 Notes on grapefruit juice:
May interact with almost all types of drugs.

20. Licorice:
Licorice Juice.
 Common interactions with:
Antihypertensives (ACEi, ARBs, CCB), Diuretics,
 Results in:
Mineralocorticoid excess via presence of glycyrrhetinic
acid in licorice which blocks activity of 11B-hydroxsteroid
dehydrogenase ultimately causing high blood pressure and
salt and water retention.
It decreases antihypertensives effect.
 Solution:
Avoid licorice derivatives when suffering from HTN,
Conn’s Disease, and when using antihypertensives.

21. Omega 3 Rich Fish:
Tuna, Sardine, Salmon, Mackerel, etc.
 Common interactions with:
Antiplatelets and anticoagulants (aspirin, clopidogrel,
warfarin, heparin, alteplase, etc)
 Results in:
Increased risk of bleeding.
 Solution:
Avoid concomitant use of omega 3 –
Containing foods with the above
Drugs.

22.  High Fat Meals may elevate the plasma levels
of Griseofulvin. Patients should be instructed to
to take griseofulvin after a high-fat content
meal.
 Protein Rich Foods may increase the
bioavailability of Propranolol.
 Orange juice may interact with drugs like
Fexofenadine, Atenolol or Fluoroquinolones and