Drug and Food Interactions

Drug Interactions

Warfarin and Amiodarone

  • If warfarin and amiodarone are taken together, there will be higher levels of free warfarin and amiodarone because they compete for binding sites.
  • Both drugs can be harmful, and a compatibility check is needed. These medications don't work well together, so call the pharmacy.

Anticoagulants and Vegetables

  • Anticoagulants include Eliquis, heparin, warfarin, and others.
  • Consuming vegetables can decrease the effectiveness of anticoagulants, essentially canceling out their effect.
  • This can lead to bleeding issues instead of appropriate coagulation.
  • Example: If a patient is taking Coumadin and eating a lot of spinach or dark green salad, this can be problematic.

Grapefruit Interactions

  • Grapefruits have many negative interactions with numerous medications.
  • Recommendations:
    • If medications are taken in the morning, consume grapefruit in the evening.
    • If medications are taken at night, consume grapefruit in the morning.
    • Maintain at least an eight-hour gap between medication intake and grapefruit consumption.

Liquorice and Digoxin

  • Liquorice and digoxin do not interact well.
  • The combination can cause hypokalemia (low potassium levels).

Aged Cheese, Wines, and MAOIs

  • Aged cheese and wines can cause hypertensive crises when taken with MAOIs (Monoamine Oxidase Inhibitors).
  • Hypertensive crisis: Blood pressure spikes to dangerous levels and is difficult to control due to the presence of aged cheese and wine in the system. Educate patients taking antihypertensive medications about this interaction.

NSAIDs and Antidepressants

  • NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) can cause GI bleeds.
  • Taking NSAIDs with antidepressants worsens the risk of GI bleeds.
  • Important: Warn patients about this interaction if they are taking both types of medications.

Antacids

  • Antacids, such as calcium carbonate, interact with many medications.
  • Space out the timing: Take the medication first, and then take the antacid after a meal to allow time for absorption.

St. John's Wort

  • St. John's Wort can reverse the effects of oral contraceptives.
  • This can lead to breakthrough bleeding, ovulation, and potentially unwanted pregnancies.

Case Study: OTC Meds and Prescriptions

  • Scenario: A patient is taking OTC meds (Advil, Tylenol, Motrin) along with prescribed medications (warfarin, lisinopril, amlodipine, Clomax).

  • Warfarin and Advil interaction:

    • This combination is dangerous and can lead to intestinal lining perforation.

  • Actions:

    • The doctor should be informed to discontinue Advil and Tylenol.
    • Hold the Advil and Tylenol until the pharmacist can remove them.
    • Patient education is crucial to ensure the patient understands the risks of taking NSAIDs (like Advil) with their medications.
    • Amlodipine and lisinopril are often lifelong medications.
    • Warfarin might be changed to another anticoagulant.
    • The primary concern is the interaction between Advil (NSAIDs) and medications that cause GI erosion.