Enter a drug or medication name to check for possible drug interactions. Always be sure to consult with your health care provider about how your medications should be managed, before making any changes.
A drug interaction refers to the effects that occur when two or more medications interact with each other in the body. These interactions can alter the way one or both substances work, potentially leading to unexpected side effects or reducing the effectiveness of the treatment.
Drug interactions can occur in several ways. One substance may enhance or inhibit the effects of another, leading to either increased therapeutic benefits or adverse reactions. Additionally, interactions can affect the absorption, distribution, metabolism, or excretion of drugs, impacting their concentration and duration in the body. This is known as a pharmacokinetic interaction. And finally, drug interactions can result in altering the behavior of one or both drugs, so that it impacts the body differently than intended. This is called pharmacodynamic interaction.
Some interactions may be predictable based on the known properties of the substances involved, while others may be unexpected and occur only in certain individuals or under specific conditions.
The symptoms of a drug interaction can vary widely depending on the substances involved, their dosages, and your specific physiology. Some common signs that may indicate a drug interaction include:
- Increased or unexpected side effects: If you are experiencing new or intensified side effects that are not typically associated with either medication you’re taking, it could be due to a drug interaction.
- Changes in treatment effectiveness: If your medication seems to be less effective than usual, it could be due to a drug interaction that is interfering with absorption, metabolism, or the medication’s action.
- Changes in health metrics: Higher or lower blood pressure, heart rate, respiratory rate, or body temperature may indicate a drug interaction.
- Changes in mental status: Confusion, agitation, hallucinations, or other changes in mental function can sometimes result from drug interactions.
- GI distress: Nausea, vomiting, diarrhea, constipation, or other digestive issues may occur if the drug interaction affects the gastrointestinal tract.
- Allergic reactions: Rash, itching, swelling, or difficulty breathing (among others) can sometimes be triggered by drug interactions.
- Worsening of underlying condition: If you’re living with a chronic condition, a drug interaction may exacerbate symptoms.
Not all drug interaction symptoms are immediately apparent. If you are experiencing unexpected or concerning symptoms while taking medications, talk with your doctor to make sure your meds are not the cause.
If you’re concerned about one of your medications potentially interacting with another medication, there are a few ways you can check before taking the drug. First, talk with your doctor. Your primary care physician, pharmacist, or other health care provider can review your complete medication list, including prescription drugs, over-the-counter medications, supplements, and herbal remedies, to identify potential interactions.
Next, make use of online databases (like this one) where you can enter the names of the medications you're taking to check for potential interactions. Most online drug interaction checkers draw on large government databases or manufacturer information. Pharmaceutical companies are required to provide information about potential drug interactions, either on the label and/or in the package insert, so be sure to carefully read this information when starting a new medication.
Drug interactions can extend beyond other medications. Certain foods and beverages can also interact with various drugs. Pay attention to any dietary restrictions or recommendations provided with your medications and consult your health care provider if you have questions.
Even with all these interaction checks in place, it’s possible to take medication that affects another drug you’re on. Always look for unusual symptoms or changes in how you feel after starting a new medication or changing the dosage of an existing one. If you experience any unexpected side effects or worsening of symptoms, report them to your doctor.
To minimize the risk of drug interactions, consider the following strategies:
- Keep a medication list: Maintain an updated list of all the meds you are taking, including prescription drugs, over-the-counter medications, vitamins, supplements, and herbal remedies. Before starting any new medication, share this list with your doctor and pharmacist for review.
- Keep your doctor in the loop: When your current provider or any new specialist you may see, make sure they are aware of all medications you are currently taking, including supplements and over-the-counter drugs. Be sure to mention any allergies or sensitivities you have to medications. Ask questions anytime you’re unsure about a medication or need clarification.
- Use a single pharmacy: When possible, have all your prescriptions sent to the same pharmacy. Pharmacists can help identify potential interactions and provide guidance.
- Read the label: Don’t assume your doctor will catch all potential interactions. Carefully read the labels and package inserts of all medications you are prescribed or purchase over the counter. Look for information about potential drug interactions, contraindications, and precautions.
- Be aware of alcohol’s effect: Alcohol and certain recreational drugs can interact with medications and cause adverse effects. Consult your health care provider about alcohol consumption and the use of illicit drugs while taking medications.
- Take as directed: It’s important to follow dosage instructions and take medications exactly as prescribed. Taking more than the recommended dose or changing the dosing schedule can have adverse health effects so always consult your doctor first.
- Don’t ignore supplements: Herbal remedies, vitamins, and dietary supplements can also interact with medications. Make sure you include these things on any list you provide your doctor or pharmacist so they can check in advance for drug interactions.
There are a vast number of possible interactions and variations based on your medical condition and circumstances. According to Pharmacy Times, these are some significant and frequently encountered drug interactions:
- Fluoxetine and phenelzine
- Digoxin and quinidine
- Sildenafil and isosorbide mononitrate
- Potassium chloride and spironolactone
- Clonidine and propranolol
- Warfarin and diflunisal
- Theophylline and ciprofloxacin
- Pimozide and ketoconazole
- Methotrexate and probenecid
- Bromocriptine and pseudoephedrine
These are just a few examples, but there are many others that your doctor will consider when prescribing you medications. It’s crucial to communicate openly with your health care provider and pharmacist about all medications, including prescription drugs, over-the-counter medications, supplements, and herbal products, to minimize the risk of potentially harmful interactions.