Philip D. Hansten, PharmD

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?

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

The last in the series of cytochrome P450 enzyme articles ends with the most important enzyme-CYP3A4, which metabolizes approximately half of all the drugs on the market.

The level at which prescribers accurately identify and manage drug?drug interactions has recently been debated. Pharmacists are in a key position to help avoid common drug?drug interactions.

The enzyme CYP2D6 affects the metabolism of many drugs, and its effect is altered by genetic variability.

Genetic variations can impact warfarin metabolism.

Drugs metabolized by CYP2C19 often have other pathways. An individual's genetic makeup may alter the activity of CYP2C19; it also is involved in important drug interactions.

By careful monitoring of patients who are prescribed clopidogrel, drugs likely to reduce its effectiveness can be avoided.

An in-depth look at CYP2C9, an enzyme involved in many clinically important drug interactions.

Awareness prevents complex drug interaction with carbamazepine.

Pharmacists have a key role to play in educating patients about the risk of stopping certain medications.

Pharmacists are an important source of drug interaction information for patients wishing to use complementary and alternative medications. In addition to discussing the possible benefits, the pharmacist can carefully evaluate the patient's medical record for potential interactions.

This enzyme is increasingly involved in drug interactions as new medications metabolized by it are released.