Herb-food interactions

Herb-food interactions

Ø  A
food – drug interaction  occurs when a
food, or one of  its components,
interferes with  the effects of a drug in
the  body

Ø  The
content of certain foods  interact with
some drugs and  produce alterations in
the  pharmacokinetics and
pharmacodynamics of the drug

Adverse Drug-food interactions

Ø  Prevent
the therapeutic effect of  a medicine

Ø  Exaggerate
the therapeutic effect  of a medicine

Ø  Make
a side effect worst

Ø  Cause
a new side effect

Liquorice / Licorice

Ø  Common
interactions with:

Digoxin, immunosuppressant’s, (cyclosporine),   


Ø  Results

       Glycyrrhetinic  acid in licorice which blocks activity of
11B-hydroxsteroid dehydrogenase ultimately causing high blood pressure and  salt and water retention

decreases antihypertensive effect

Ø  Solution:

licorice derivatives when suffering from Hypertension,  Conn’s Disease, and when using

Omega 3 rich fishes

Tuna, Sardine, Salmon, Mackerel, etc.

Ø  Common
interactions with:

and anticoagulants (aspirin, clopidogrel, 
warfarin, heparin, alteplase, etc)

Ø  Results

Ø  Increased
risk of bleeding


concomitant use of omega 3 –  Containing
foods with the above  Drugs

Caffeine Drinks

Coffee, tea, energy drinks, soft drinks, etc

Common interactions with:

Ø  Theophylline,
Prednisolone, OCPs,  Ciprofloxacin,

Results in:

Ø  Inhibition
of Theophylline metabolism with subsequent adverse effects of it. (Jitteriness,
Insomnia, and Cardiac arrhythmias)

Ø  Reduced
caffeine metabolism leads to subsequent 
increased effects of caffeine

Grape Juice

Common interactions with:

Ø  Statins
(increased risk of rhabdomyolysis), erythromycin, domperidone, amiodarone
(increased risk for                QT
prolongation), immuno suppressants (cyclosporine, Tacrolimus,, inhibiting
its  metabolism with increased risk of
nephrotoxity), opioids (fentanyl, 
ketamine, oxycodone, inhibiting their metabolism with increased risk of  respiratory depression).

Vit K rich foods

Foods rich in Vit K – Kale, Collards, Spinach, Turnip
greens, Brussels sprouts and Broccoli, 

Common interactions with:

Ø  Warfarin
(Blood thinning agents that prevents blood clots)

Results in:

Ø  Increased
intake of vit K foods – risk of thrombosis (blood clots).

Ø  Reduced
intake  – increase risk of bleeding

Other Interactions

Ø  High
Fat Meals
may elevate the plasma levels of Griseofulvin. Patients
should be instructed not  to take
griseofulvin after a high-fat content meal

Ø  Protein
Rich Foods
may increase the bioavailability of Propranolol

Ø  Orange
may interact with drugs like 
Fexofenadine, Atenolol or Fluoroquinolones


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