* We have already discussed the importance of the interaction between grapefruit juice and CYP3A4.
* Another important food drug interaction exists with monoamine oxidase (MAO) inhibitors, a class of drug used to treat depression.
* Patients taking these drugs must avoid foods containing tyramine including aged cheese, yeast, red wine, sauerkraut, cured meat (i.e. pepperoni) and soy sauce.
* MAO inhibitors inhibit the breakdown of tyramine.
* Tyramine causes increased release of norepinephrine from peripheral nerve terminals resulting in a potentially fatal hypertensive crisis.
* Symptoms of hypertensive crisis include tachycardia (increased heart rate), severe hypertension, headache, nausea and vomiting.
* MAO inhibitors should not be used in patients not capable of adhering to strict dietary restrictions.