Drug Interactions: 5 Reasons Why
Metabolism is the body’s ability to alter medications so they can efficiently be used to treat the illness, and then be eliminated. The liver, the primary site of medication metabolism, breaks down the medication through a complex system of enzymes. Medication elimination is primary through the kidneys (pee) and intestinal tract (poop).
What can affect medication metabolism?
· Other medications
· Kidney and liver function
If these factors decrease the breakdown of a medication, that medication's effects are increased, as there is more medication in the blood stream. If these factors increase the breakdown of a medication, that medication's effects are decreased, as there is less medication in the blood stream.
Types of Drug Interactions
Drug-Drug interaction: This occurs when two medications with the same action are taken.
· People may take a cold remedy and a sleep aid, both of which contain diphenhydramine (Benadryl), or a cold remedy and a pain reliever, both of which contain acetaminophen (Tylenol)
· The allergy medication, loratadine, is also marketed as Claritin and Alavert
Opposition is when two medications with opposite actions are taken, reducing the effectiveness of one or both.
· Ibuprofen (Motrin, Advil) and naproxen (Aleve) may cause the body to retain fluid. Diuretics (‘water pills’), such as hydrochlorothiazide and furosemide, help rid the body of excess fluid. If a person takes both types of medication, the ibuprofen or naproxen may reduce the diuretic's effectiveness
Alteration is when one medication alters how the body absorbs, distributes, metabolizes, or excretes another medication.
· Proton pump inhibitors (PPI), such as Nexium and Prevacid, decrease stomach acid production, relieving the symptoms of acid reflux. Stomach acid plays a role in the absorption of nutrients, prevention of intestinal infection, and medication metabolism. A change in stomach acid production can interfere with all 3 actions
Drug with Food/Beverage interactions include delayed, decreased, or enhanced absorption of a medication.
· Grapefruit juice can increase medication levels in your body, increasing the likelihood of side effects. (https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm292276.htm)
· Caffeine can interact with stimulant drugs such as Ritalin (methylphenidate), increasing their effect, or by decreasing the effect of sleeping pills, such as Ambien (zolpidem)
Drugs with Dietary Supplement interactions:
· St. John's Wort increases the liver’s ability to break down medications (reducing the blood concentration) in cholesterol-lowering medications and Viagra
· Ginseng can increase the bleeding effects of heparin, aspirin, and ibuprofen
Drug-Disease interactions: Medications that are helpful for one disease can be harmful to another.
· Over-the-counter oral decongestants, like pseudoephedrine (Sudafed) or phenylephrine, can increase blood pressure in those with and without a diagnosis of high blood pressure
· Some antihistamines can cause difficulty in urination in men who have an enlarged prostate gland, and make glaucoma worse in people who have this disease
· Keep an up-to-date medication list and bring it to each medical visit
· Your medical provider and pharmacist can check for medication interactions, and if any are present, explain their significance to you
· Don’t stop your medication without talking to your medical provider first
· Don’t take previously prescribed medications without checking with your medical provider or pharmacist, as they may interact with one of your current medications
Know that your medical provider may prescribe you medication with known drug interactions. It is their job to weigh the risks and benefits of each medication with regard to your personal health. They will understand the relevance of each interaction, and will be able to recommend the next best steps you should take.