Changes caused by one drug in the absorption, distribution, metabolism or excretion of another may lead to a pharmacokinetic adverse drug interaction (DN Juurlink et al, JAMA 2003; 289:1652). Additive drug interactions, such as vasodilation caused by both sildenafil (Viagra) and nitrates, can also have adverse effects.

The FDA has approved edoxaban (Savaysa – Daiichi Sankyo), a once-daily, oral, direct factor Xa inhibitor, for treatment of venous thromoboembolism (VTE) and for prevention of stroke and systemic embolism in patients with nonvalvular atrial fibrillation. It is the fourth new oral anticoagulant to be approved for VTE and nonvalvular atrial fibrillation.

Ciprofloxacin, previously available orally (Cipro - Medical Letter, 30:11, 1988) and for ophthalmic use (Ciloxan - Medical Letter, 33:52, May 31, 1991), is now the first fluoroquinolone antibiotic to become available in the USA in an intravenous (IV) formulation. Cipro I.V. (Miles) is being promoted as an alternative to third-generation cephalosporins, aminoglycosides, and other drugs used for treatment of serious infections.

Colesevelam hydrochloride (Welchol - Sankyo Pharma), a nonabsorbed hydrophilic polymer that binds bile acids, has been approved by the FDA for reduction of plasma LDL cholesterol in patients with primary hypercholesterolemia.

Atrial fibrillation increases the risk of stroke by a factor of 5. A randomized controlled trial (ACTIVE W) in 6706 patients with atrial fibrillation and one or more additional risk factors (≥75 years old; hypertension; previous stroke, transient ischemic attack or non- CNS embolus; left ventricular ejection fraction <45%; peripheral vascular disease; or 55-74 years old plus diabetes or coronary artery disease) found that a vitamin K antagonist such as warfarin (Coumadin, and others) was superior to clopidogrel (Plavix) plus aspirin in preventing vascular events, especially ischemic...

Zafirlukast (za fir loo kast; Accolate - Zeneca), the first leukotriene receptor anta-gonist approved by the US Food and Drug Administration, is now being heavily promoted for oral maintenance treatment of chronic asthma in patients more than 12 years old. It is not recommended for treatment of acute asthma.

Cerivastatin (Baycol - Bayer), a new HMG-CoA reductase inhibitor (or "statin"), has been approved by the FDA for treatment of hypercholesterolemia. Cerivastatin is the sodium salt of a synthetic fluorophenyl pyridinyl-substituted heptanoic acid.

Dofetilide (Tikosyn - Pfizer), a new methanesulfonamide antiarrhythmic drug, has recently been marketed for oral treatment of atrial fibrillation and flutter.

The FDA has approved rivaroxaban (Xarelto – Janssen), an oral direct factor Xa inhibitor, for prevention of deep vein thrombosis (DVT) in patients undergoing knee or hip replacement surgery.

Major orthopedic surgery creates a prothrombotic state by causing tissue injury during the operation and requiring relative immobilization during recovery. Without thromboprophylaxis, 40-60% of patients undergoing major knee or hip surgery develop venographically detectable deep vein thrombosis (DVT) and 1 in 300 undergoing total hip replacement will have a symptomatic pulmonary embolism (PE). Thromboprophylaxis reduces the incidence of venous thromboembolism (VTE), but it also can cause bleeding. New guidelines for prevention of VTE have recently been published.