Whether you’re picking up a new antibiotic from the pharmacy or renewing your cholesterol medication, you often get counseled by the pharmacist regarding certain drug-food interactions. Many people are aware that these interactions exist – but just how real and serious is this issue?
The main mechanism behind drug-food interaction is dependent on how the body breaks down the medication. Enzymes known as the cytochrome P450 enzymes allow the body to metabolize and gradually degrade the medications after administration. Certain foods are able to inhibit or potentiate the action of these enzymes. This in turn can lead to too much drug in the body (i.e. increased side effect or toxicity) or too little drug in the body (sub-therapeutic effect). Other interactions between medications and certain foods can take place by hindering with the absorption of the medication or by amplifying the existing side effects of the medication.
Many different food groups interact with medications. While I am unable to give a comprehensive list of all the interactions, I’ll mention few that are worthwhile to know about.
- Grapefruit juice: Grapefruit juice is one of the most notorious offenders for causing drug-food interactions. Grapefruit juice inhibits a major subtype of P450 enzyme that metabolizes cholesterol medications such as atorvastatin, lovastatin, and simvastatin. Blood pressure medication such as amlodipine is also affected by this interaction. By inhibiting the enzyme, grapefruit juice allows the medication to stay in the body for a longer duration and increases the possibility of experiencing side effects. Drugs that interact with grapefruit juice should not be taken together within the same 24 hour period since the inhibition of P450 enzyme by grapefruit juice leaves a long-lasting effect.
- Alcohol: The interaction between
alcohol and medications doesn’t necessarily involve the CYP P450 enzymes but
mostly on the effect of the medication. For instance, any medications that can
cause drowsiness or sedation can be worsened if taken alongside alcohol. These
medications include antihistamines, muscle relaxants and even some painkillers.
Although this interaction may not diminish the efficacy of the medications, it
is best to separate t
heir administration to avoid serious side effects.
- Dairy products: This category extends beyond just dairy products but also encompasses calcium or iron supplements. The major concern regarding dairy products is with thyroid medication (i.e. levothyroxine) and certain antibiotics known as the fluoroquinolones. Dairy products and mineral supplements hinder the absorption of these medications and lower their efficacy. These medications should be spaced out by minimum 1 hour before or 2 hours after dairy products are consumed.
If you’re unsure about your medications and whether it interacts with certain groups, check out a great online resource from FDA and be sure to ask your pharmacist on your next visit!