Orally ingested medicines either prescribed or purchased over the counter can have unwanted interactions when consumed with certain food and drinks. It is usually referred to as drug-food interaction; this happens with certain foods either causing a delay or quickening the absorption of the medicine.
Food interaction with your medicine will usually cause a reaction or increase the chances of the side effects. There are other factors such as age, weight, disease condition and a dose of medication that can also affect your medicines. It is therefore recommended that you speak to your pharmacist whenever the need arises to take certain medicines with food, herbal supplements, and vitamins that are purchased over the counter. In some instances, certain medication is taken on an empty stomach while some are recommended to be consumed with food.
The following food, drinks or supplements have been put together as a reference to guide you with food-drug interaction.
- Grapefruit and Grapefruit juice can affect the absorption of statins (drugs used in lowering cholesterol) thereby causing an increased risk of the side effects of some statins. It is recommended that people on statins should avoid taking grapefruit and grapefruit juice. Grapefruit also can affect Fexofenadine (drugs used for allergies) when consumed together. Grapefruit juice can also increase blood levels of Sildenafil (used in treating erectile dysfunction). Some oral contraceptives have also been documented to be affected by grapefruit juice when consumed together. It has also been advised that some immunosuppressant such as Tacrolimus should not be consumed with grapefruit juice.
- Dairy products such as milk and yoghurt can affect certain antibiotics such as Tetracycline, Doxycycline, Ciprofloxacin and cephalosporin rendering them inactive. This occurs due to calcium in the dairy product causing a chemical interaction. It is advisable to leave at least two hours apart before consuming some of these antibiotics to minimise interaction. Antacids and dairy products should also be avoided.
- Alcohol interacts with many drugs such as benzodiazepines, antihistamines, opiates, anticonvulsants and antipsychotics when taken together. Alcohol can cause an increase in injury, falls and accidents. A serious reaction called ‘disulfiram’ effect (vomiting, flushing and increased heart rate or tachycardia) occurs when alcohol is consumed with Metronidazole, Sulfonylureas and Isoniazid.
- Green leafy vegetables such as broccoli, spinach are good sources of vitamin K. It is recommended that people taking warfarin (oral anticoagulant) should maintain the same level of vitamin k to prevent an increase in clotting factors that will result in low efficacy of Warfarin.
- Ginseng is a herbal supplement usually obtained over the counter. They can enhance the effects of aspirin, warfarin and non-steroidal anti-inflammatory drugs such as ibuprofen. When ginseng is taken with some monoamine oxidase inhibitors (MAOI) they may cause headaches, hyperactivity and sleeping disturbances.
- Over the counter herbal remedy, St John’s Wort used by some people in managing depression has also been found to affect a few prescription drugs such as Sildenafil (used in treating erectile dysfunction), digoxin (used in treating heart conditions such as heart failure).
- Caffeine found in tea, coffee and beverages also interact with some medicines. Antibiotic such as Ciprofloxacin affects the metabolism of caffeine thereby causing increased effects of caffeine. Some drugs such as cimetidine also cause an increase in caffeine levels. It is also documented that caffeine should be avoided in patients taking Theophylline used in the management of asthma.
- Sodium present in salt should be avoided in patients taking lithium and the moderate amount should be consumed in people with high blood pressure.
- Excessive intake of potassium (found in Banana, apricots, prunes, dates, oranges, cucumbers, sweet potatoes, red meat) should be avoided in patients taking spironolactone (a diuretic) and angiotensin-converting enzyme inhibitors (ACEI) such as Ramipril, Enalapril, Lisinopril used in the treatment of high blood pressure as these drugs cause an increase in potassium levels in the body.
- Ensure you speak to your pharmacist or healthcare professional before taking a new medicine including supplements and vitamins.
- Read warning labels and information leaflets attached to your medicine even those purchased over the counter.
- Take medicine with water unless otherwise instructed
- Do not mix your medicines with food, hot drinks as they may affect the efficacy of the medicine.
- Avoid consuming alcohol with your medicines.
- Some drugs are better taken on an empty stomach such as the proton pump inhibitors such as Omeprazole, Lansoprazole or Esomeprazole.
- Ensure you take the following medicines (Ibuprofen, Aspirin, naproxen) with food as they can upset your stomach when ingested on empty stomach.