The FDA has required the manufacturer of the secondgeneration antipsychotic quetiapine (Seroquel) to add a warning to the labeling saying that use of the drug should be avoided in combination with other drugs that prolong the electrocardiographic QTc interval (Table 1). The warning is based only on postmarketing reports of QT-interval prolongation in patients who overdosed on the drug, had concomitant illness, or were taking other drugs known to cause electrolyte imbalances or increase the QT interval. QT prolongation can lead to torsades de pointes, a potentially fatal cardiac arrhythmia.

The treatment of atrial fibrillation includes ventricular rate control, anticoagulation, conversion to normal sinus rhythm and maintenance of sinus rhythm. The choice of therapies that can achieve these goals is discussed in the text that follows. Some drugs are recommended here for indications that have not been approved by the FDA.

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.

Many drugs can cause psychiatric symptoms, but a causal connection is often difficult to establish. Psychiatric symptoms that emerge during drug treatment could also be due to the underlying illness, previously unrecognized psychopathology, or psychosocial factors. The withdrawal of some drugs can cause symptoms such as anxiety, psychosis, delirium, agitation or depression.

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The drugs of choice for treatment of common cardiac arrhythmias are listed in Tables 1 and 2. Some drugs are recommended for indications that have not been approved by the FDA.

The drugs of choice for treatment of common cardiac arrhythmias are listed in the table that begins on the next page; some drugs are recommended for indications for which they have not been approved by the US FDA. The dosages and adverse effects of each drug are listed in the table that begins on page 80. Antiarrhythmic drugs may themselves cause arrhythmias, which can be fatal. Some of these drugs may increase rather than decrease mortality, especially in patients with structural heart disease.

Trospium chloride (Sanctura - Indevus/Odyssey) has been approved by the FDA for treatment of overactive bladder with symptoms of urge urinary incontinence, urgency and urinary frequency. It has been available in Europe for many years.

Vardenafil (Levitra -Bayer) is the second oral drug approved by the FDA for treatment of erectile dysfunction. Sildenafil (Viagra - Medical Letter 1998; 40:51), the first oral drug, has been available for 5 years. Pharmacokinetics, effectiveness, adverse effects, dosage and cost of the new drug are reviewed. Whether it offers any benefits over sildenafil is discussed.

Ever-increasing specialization has made it difficult for many physicians to keep up with therapeutic standards in intensive-care units (ICUs). This issue of Treatment Guidelines offers current recommendations for use of cardiovascular drugs in the ICU for treatment of hypertensive emergencies; shock, cardiac arrest or decompensated heart failure; and ventricular arrhythmias.

Many drugs can cause psychiatric symptoms, but a causal connection is often difficult to establish. Psychiatric symptoms that emerge during drug treatment may also be due to the underlying illness, previously unrecognized psychopathology, or psychosocial factors. The withdrawal of some drugs can cause symptoms such as anxiety, psychosis, delirium, agitation or depression.

Older patients are especially susceptible to drug-induced cognitive impairment. They are more likely to be taking multiple drugs, to have higher blood levels of those drugs because of renal or hepatic dysfunction, and to have pre-existing cognitive problems that make it difficult to detect the role of drugs causing new symptoms or making old ones worse.

Penciclovir 1% cream (Denavir - SmithKline Beecham) has been approved by the US Food and Drug Administration (FDA) for treatment of recurrent orolabial herpes simplex virus (HSV) infections in adults. Acyclovir (Zovirax) is also available in a topical formulation for treatment of herpes simplex infections, but is approved by the FDA only for use in immunocompromised patients. Oral drugs approved for treatment of some herpes simplex infections, but not recurrent orolabial infections, include acyclovir, valacyclovir (Valtrex) and famciclovir (Famvir), which is rapidly hydrolyzed to penciclovir in vivo (Medical Letter, 36:97, 1994).

Sotalol (hydrochloride (Betapace -Berlex; Sotacor -Bristol Laboratories of Canada), an antiarrhythmic drug that prolongs repolarization (Class III) and also has beta-adrenergic-blocking activity (Class II), was recently approved by the US Food and Drug Administration (FDA) for oral treatment of life-threatening ventricular arrhythmias.

Flecainide (Tambocor -3M Pharmaceuticals), first introduced in 1985 for treatment of ventricular arrhythmias, was recently approved by the US Food and Drug Administration for oral use to prevent supraventricular arrhythmias. The indications for using flecainide to treat ventricular arrhythmias were limited after a controlled trial found that post-myocardial infarction patients with asymptomatic ventricular arrhythmias who took the drug had twice as high a mortality rate as patients who took placebo (DS Echt et al, N Engl Med, 324:781, 1991).