https://reference.medscape.com/drug-interactionchecker
https://www.rxlist.com/drug-interaction-checker.htm
https://healthtools.aarp.org/drug-interactions
Drugs can interact with each other by enhancing or inhibiting the metabolism of other drugs.
May involve drug metabolizing enzymes and cellular transport proteins.
The effects of drug interactions are usually unwanted and sometimes harmful.
Drug Interactions
The effects of drug interactions are usually unwanted and sometimes harmful.
Interactions may increase or decrease the actions of one or more drugs, resulting in side effects or failed treatment.
Drug-drug interactions can involve prescription or nonprescription drugs.
Types of drug-drug interactions include duplication, antagonism, and alteration of what the body does to one or both drugs.
When two agents with the same effect, their side effects may be increased.
Duplication may occur when one inadvertently take two drugs that have the same active ingredient.
Similar duplication can arise when two different drugs with the same effect are taken.
Two drugs with opposing actions can interact, thereby reducing the effectiveness of one or both.
One drug may alter how the body absorbs, distributes, metabolizes, or excretes another drug.
Acid-blocking drugs, such as histamine-2 (H2) blockers and proton pump inhibitors, raise the pH of the stomach and decrease absorption of some drugs.
Many drugs are broken down and metabolized by certain enzymes in the liver, either increasing or decreasing their activity, and may cause another drug to be inactivated more quickly or more slowly than usual.
Chemicals in cigarette smoke can increase the activity of some liver enzymes.
Some drugs affect the rate at which the kidneys excrete another drug.
Interactions may increase or decrease the actions of one or more drugs, resulting in side effects or failed treatment.
Drug-drug interactions can involve prescription or nonprescription drugs.
Types of drug-drug interactions include duplication, antagonism, and alteration of what the body does to one or both drugs.
When two agents with the same effect, their side effects may be increased.
Duplication may occur when one inadvertently take two drugs that have the same active ingredient.
Similar duplication can arise when two different drugs with the same effect are taken.
Two drugs with opposing actions can interact, thereby reducing the effectiveness of one or both.
One drug may alter how the body absorbs, distributes, metabolizes, or excretes another drug.
Acid-blocking drugs, such as histamine-2 (H2) blockers and proton pump inhibitors, raise the pH of the stomach and decrease absorption of some drugs.
Many drugs are broken down and metabolized by certain enzymes in the liver, either increasing or decreasing their activity, and may cause another drug to be inactivated more quickly or more slowly than usual.
Chemicals in cigarette smoke can increase the activity of some liver enzymes.
Some drugs affect the rate at which the kidneys excrete another drug.
Most drug-drug interactions occur in the liver, but they may also involve intestinal CYP enzymes.
Terfenadine, an antihistamine has been removed from the market because of drug-drug interaction.
Terfenadine when coadministered with ketoconazole, a CYP 34 inhibitor increased plasma concentrations of terfenadine were reported and resulted in life-threatening and fatal cardiac arrhythmias.
Additional drugs been withdrawn for this market because of drug-drug interactions include mibefradil an antihypertensive agent, astemizole, an antihistamine and cisapride a gastrointestinal agent.
TMP-SMX interactions with warfarin are the most common serious drug interactions encountered with warfarin.
The average increase in INR is 1.76 for patients taking TMP-SMX.
Warfarin interaction that increases INR occur with erythromycin, amiodarone, fluconazole, ketoconazole, itraconazole, and metronidazole.
Warfarin interaction with acetaminophen is significant when patients take regular daily acetaminophen, with increased INR.
Warfarin-steroids interaction results in significant increases in INR.