Tetrabenazine (Xenazine - Ovation Pharmaceuticals), an old drug first synthesized 50 years ago for treatment of schizophrenia, was recently approved by the FDA for the treatment of chorea associated with Huntington's disease. It has been available in other countries for decades.

The ability of grapefruit juice to increase serum concentrations of drugs was first discovered during a study of the effect of ethanol on felodipine (Plendil) pharmacokinetics. Double-strength grapefruit juice used to disguise the taste of ethanol resulted in higher than expected serum concentrations of felodipine (DG Bailey et al, Clin Invest Med 1989; 12:357).

Dronedarone (Multaq - Sanofi-Aventis) has been approved by the FDA for oral treatment of atrial fibrillation and flutter. Amiodarone (Cordarone, and others) is the most effective drug for this indication, but has considerable toxicity.

As the weather becomes warmer, physicians may see more photosensitivity reactions due to systemic or topical drugs, perfumes, cosmetics or sunscreens. Even brief exposure to sunlight in warm or cold weather can cause intense cutaneous reactions in patients with drug-induced photosensitivity, and some patients may continue to be sensitive to sunlight long after stopping use of the offending agent.

Previously approved by the FDA for treatment of depression, general anxiety disorder, diabetic peripheral neuropathic pain and fibromyalgia, duloxetine (Cymbalta – Lilly) has now also been approved for treatment of chronic musculoskeletal pain.

Venlafaxine hydrochloride (Effexor - Wyeth-Ayerst) was recently approved by the US Food and Drug Administration for treatment of depression. An aminomethyl-benzyl- cyclohexanol, it is chemically related to bupropion (Wellbutrin).

An intravenous formulation of amiodarone (Cordarone IV -Wyeth-Ayerst) has been approved by the US Food and Drug Administration (FDA) for treatment and prophylaxis of recurrent ventricular fibrillation (VF) or hemodynamically unstable ventricular tachycardia (VT) in patients refractory to other therapy.

The FDA has added a "black box" warning about the risks of QT prolongation and the potentially fatal torsades de pointes (TdP) ventricular tachycardia to the labeling of droperidol (Inapsine - Akorn), an antiemetic used mostly in anesthesia. The Canadian Health Protection Branch has issued a similar warning. Some anesthesiologists have written to The Medical Letter to express their displeasure with these warnings.

Alzheimer's disease (AD) is the most common cause of dementia, but cognitive decline is also associated with other neurological conditions such as Parkinson's disease, dementia with Lewy bodies, vascular dementia, and frontotemporal dementia.

The FDA has approved the marketing of fingolimod (Gilenya – Novartis) to reduce the frequency of clinical exacerbations and delay the accumulation of physical disability in patients with relapsing forms of multiple sclerosis (MS). Fingolimod is the first oral drug approved for this indication.