John R. Horn, PharmD, FCCP

Pharmacists should closely monitor patients who take trimethoprim and other drugs that increase serum potassium.

Although triple drug interactions are not well studied, available information points to some general principles that may be useful in managing such combination.

Patients taking dabigatran etexilate should be closely monitored for altered responses to this newly approved oral anticoagulant.

A recent study revealed gender differences in the severity of interactions between metoprolol and diphenhydramine.

Simple calculations can be used to help pharmacists evaluate a drug interaction and its potential to cause significant harm.

When faced with drug interaction alert, pharmacists should assess the level of risk and have a standardized action plan in place for staff members to follow.

Because many patients who take bisphosphonates also take nonsteroidal anti-inflammatory drugs for other conditions, it is important to determine if their combination will have a negative effect.

New case reports and clinical trials are examined that provide additional evidence on the interaction between cranberry juice and warfarin.

Some debate exists surrounding the use of menthol cough drops in patients on warfarin because of altered international normalized ratio levels-is there enough evidence to prove a direct correlation?

Tyrosine kinase inhibitors (TKIs) are indicated for the treatment of a variety of malignancies due to their ability to interfere with cell communication and growth. Interactions that affect TKI metabolism are discussed.

The debate surrounding whether an interaction occurs between oral contraceptives and antibiotics continues. It the use of antibiotics with oral contraceptives likely to result in an unintended pregnancy?

This column is an update to the April 2008 column that discussed the possible interaction between clopidogrel and proton pump inhibitors-new studies and data are brought into perspective.

Quetiapine, an atypical antipsychotic, has become one of the most widely prescribed psychiatric medications in the United States; several reminders are presented here to ensure safe use of the drug.

Our Columnists provide an update on the many drug interactions associated with the commonly used herbal supplement, St. John's Wort.

Oatmeal is commonly touted as a healthy, cholesterol-lowering food—but does it present an interaction risk with digoxin?

Being aware of drugs that inhibit CYP2D6 is especially important for patients taking tamoxifen.

The second in a pair of articles on drug transporters, this article focuses on uptake transporters that actively pump drugs into cells.

Reducing the risk of adverse drug interactions requires taking various items into consideration, including possible outcomes.

Transporter proteins transport drugs in and out of cells and are susceptible to reduced or enhanced activity depending on drug exposure.

Proton pump inhibitors are potent inhibitors of gastric acid secretion; their interactions with protease inhibitors are discussed here.