The FDA has approved the oral second-generation antipsychotic drug brexpiprazole (Rexulti – Otsuka/Lundbeck) for once-daily treatment of agitation associated with dementia due to Alzheimer's disease (AD). Brexpiprazole is the first drug to be approved in the US for this indication. It is also approved for treatment of schizophrenia and as an adjunct to antidepressants for treatment of major depressive disorder.

The FDA has approved an extended-release fixed-dose combination of dextromethorphan and bupropion (Auvelity – Axsome) for treatment of major depressive disorder (MDD) in adults.

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.

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

The treatment of atrial fibrillation includes anticoagulation, rate control, and rhythm control. New US guidelines for the management of atrial fibrillation have recently been published.

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 FDA has approved Nuedexta (Avanir), a fixed-dose combination of the cough suppressant dextromethorphan hydrobromide and the antiarrhythmic quinidine sulfate, for oral treatment of pseudobulbar affect. The combination is the first treatment approved by the FDA for this indication. Studies to support the effectiveness of Nuedexta were performed in patients with underlying amyotrophic lateral sclerosis (ALS) or multiple sclerosis (MS); the drug has not been shown to be safe or effective in other types of emotional lability.

Attention-deficit/hyperactivity disorder (ADHD) is a disruptive behavior disorder that occurs in about 5% of school-age children, most often in boys, and frequently persists into young adulthood.

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.

Use of a selective serotonin reuptake inhibitor (SSRI) is common in women taking tamoxifen (Nolvadex, and others) for breast cancer, both to treat depression and to decrease hot flashes. However, tamoxifen must be metabolized by CYP2D6 to become pharmacologically fully active (MJ Higgins et al. J Natl Compr Canc Netw 2009; 7:203), and the SSRIs fluoxetine (Prozac, and others) and paroxetine (Paxil, and others) are strong inhibitors of CYP2D6. Sertraline (Zoloft, and others) inhibits CYP2D6 to a lesser extent. Citalopram (Celexa, and others) and escitalopram (Lexapro), the 2 other SSRIs approved for treatment of depression, are only weak inhibitors of CYP2D6.

Two observational studies presented at a recent meeting of the American Society of Clinical Oncology (45th annual meeting, May 29-June 2, 2009, Orlando, FL abstracts CRA508, CRA509) examined the effect of strong inhibitors of CYP2D6 on the success rate of tamoxifen in preventing recurrence of breast cancer. One found that women who took fluoxetine, paroxetine or sertraline (or bupropion, duloxetine, terbinafine, quinidine or long-term diphenhydramine) with tamoxifen had a higher 2-year recurrence rate (13.9% vs. 7.5%). The other study found no association between cancer recurrence and use of a CYP2D6 inhibitor.

There is no good evidence that any one SSRI is more effective than any other for treatment of depression. For women who are taking tamoxifen and need to begin treatment with an SSRI to treat depression, citalopram or escitalopram might be the safest choice (Treat Guidel Med Lett 2006; 4:35). Use of an SSRI to treat hot flashes in women taking tamoxifen should probably be reconsidered.

Download: U.S. English

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.

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.

Click here to view the free full article.

Duloxetine (Cymbalta - Lilly) is the second drug to be approved by the FDA for treatment of fibromyalgia. Pregabalin (Lyrica), which is also approved for treatment of neuropathic pain and epilepsy, was the first. Duloxetine is a selective serotonin and norepinephrine reuptake inhibitor (SNRI) that is already marketed for treatment of depression and diabetic neuropathy.

The drug of choice for patients who require parenteral treatment for malaria is IV artesunate, which is available now from the CDC Malaria Branch (M-F, 8 AM-4:30 PM eastern time, 770-488-7788 or, after hours, 770-488-7100). Artesunate appears to be more effective than quinine1 and safer than quinidine, the other parenteral alternatives in the US. The CDC has supplies of artesunate in Atlanta and in 8 quarantine stations in major airports around the US. It will release the drug for appropriate patients (severe disease or unable to take oral drugs) if it can be supplied as quickly as quinidine, or if quinidine has failed, been poorly tolerated, or is contraindicated.

The herbal artemisinin derivatives artemether and artesunate are used worldwide for treatment of malaria caused by Plasmodium falciparum, but have not been marketed in the US.2,3 About 1500 cases of malaria are diagnosed each year in the US in returning travelers, and about 5% of these have severe disease.4

Artesunate is generally given over 3 days in 2.4 mg/kg doses at 0, 12, 24 and 48 hours. It should be accompanied as soon as possible by an oral drug such as atovaquone/proguanil (Malarone), doxycycline (Vibramycin, and others; not for children <8 years old), clindamycin (Cleocin, and others) or mefloquine (Lariam, and others).

1. A Dondorp et al. South East Asian Quinine Artesunate Malaria Trial (SEAQUAMAT) Artesunate versus quinine for treatment of severe falciparum malaria: a randomised trial. Lancet 2005; 366:717.
2. Drugs for parasitic infections. New Rochelle, NY: The Medical Letter; 2007:34.
3. NJ White. Qinghaosu (artemisinin): the price of success. Science 2008; 320:330.
4. PJ Rosenthal. Artesunate for the treatment of severe falciparum malaria. N Engl J Med 2008; 358:1829.

Download: U.S. English

The drugs of choice for treatment of some fungal infections are listed in the tables. Some of the indications and dosages recommended here have not been approved by the FDA. Other guidelines are available from the Infectious Diseases Society of America (www.idsociety.org).

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.

Patients planning to travel to other countries often ask physicians for information about immunizations and prevention of diarrhea and malaria. More detailed advice for travelers is available from the Centers for Disease Control and Prevention at 877-FYI-TRIP (877-394-8747) or www.cdc.gov/travel.

Many patients planning to travel seek advice about prevention of malaria. No drug is 100% effective for this indication; travelers should be told to take other protective measures as well. Malaria in pregnancy is particularly serious for both mother and fetus; prophylaxis is indicated if travel cannot be avoided. Countries with a risk of malaria are listed in the table on page 102. Some countries with endemic malaria transmission may not have malaria in the most frequently visited major cities and rural tourist resorts.

Click here to view the free full article.

Duloxetine hydrochloride (Cymbalta - Lilly), a selective serotonin and norepinephrine reuptake inhibitor (SNRI) available for treatment of depression, has also been approved by the FDA for treatment of neuropathic pain associated with diabetic peripheral neuropathy (DPN). Duloxetine is one of two drugs approved specifically for management of neuropathic pain due to diabetes; the other, pregabalin (Lyrica - Pfizer), will be marketed soon and will be reviewed in the next issue of The Medical Letter.

Serious adverse interactions between drugs continue to be reported. Many of these are due to inhibition or induction of cytochrome P450 (CYP) enzymes, particularly CYP3A4. CYP3A is thought to be involved in the metabolism of more than 50 percent of currently prescribed drugs.2 CYP3A4, which is more abundantly expressed than CYP3A5, accounts for most CYP3A activity in vivo.

The drugs of choice for treatment of some fungal infections are listed in the table that begins on page 8. Some of the indications and dosages recommended here have not been approved by the FDA.

Tuberculosis (TB) is still a problem in the United States, even though the incidence continues to decline in most of the country (MMWR Morbid Mortal Wkly Rep 2004; 53:209). Treatment of TB can be divided into treatment of latent infection diagnosed by a positive PPD and treatment of active clinical TB. Guidelines with detailed management recommendations are available from the US Centers for Disease Control and Prevention (CDC) (MMWR Morbid Mortal Wkly Rep 2003; 52RR-11:1).

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.

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).

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.

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.

Aripiprazole (Abilify - Bristol-Myers Squibb/Otsuka), a quinolinone derivative, has been approved by the FDA for treatment of schizophrenia.

Atomoxetine (Strattera - Lilly) is the first non-stimulant drug to be approved by the FDA for treatment of attention deficit hyperactivity disorder (ADHD). Unlike other drugs approved for use in ADHD, it is not a controlled substance and is approved for use in adults as well as children. Older non-stimulant drugs that have been used to treat ADHD, although not FDA-approved, include the alpha₂-agonist clonidine (Catapres, and others) and the tricyclic antidepressant desipramine (Norpramin, and others) (Medical Letter 1996; 38:109).

When patents expire on brand-name drugs and generic formulations become available, patients and managed care organizations may express a preference for the lower-cost generics. Are they equivalent to the brand-name product?

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.

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.

Amprenavir is the fifth protease inhibitor to become available for treatment of HIV infection. It was approved by the FDA for use with other drugs in the treatment of HIV-infected adults and children at least four years old.

Reports of adverse interactions between drugs continue to accumulate. Recently, the FDA has expanded the recommendations on drug interactions found in the package inserts of new drugs.

Carvedilol (Coreg - SmithKline Beecham and Boehringer-Mannheim), a betaadrenergic and alpha-adrenergic blocker approved by the FDA for treatment of hypertension in 1995, but not marketed at that time, has now been approved and marketed for treatment of mild or moderate (NYHA class II or III) heart failure stabilized on other drugs. It is being promoted as an add-on drug that reduces the morbidity and mortality of the disease.

Midodrine hydrochloride (ProAmatine - Roberts), an alpha1-selective adrenergic agonist, is now available for treatment of severe symptomatic orthostatic hypotension. Other treatments for this condition include other sympathomimetics, constrictive garments, erythropoietin (Epogen; Procrit) and fludrocortisone with salt (D Robertson and TL Davis, Neurology, 45 suppl 5: S26, 1995).

Donepezil hydrochloride (Aricept - Eisai), a piperidine-based acetylcholinesterase inhibitor, is now being marketed for oral treatment of cognitive symptoms in patients with mild to moderate dementia due to Alzheimer's disease. Donepezil is the second drug approved for this indication; tacrine hydrochloride (Cognex), also an acetylcholinesterase inhibitor, has been available in the USA for four years (Medical Letter, 35:87, 1993).

Most peptic ulcers not caused by nonsteroidal anti-inflammatory drugs (NSAIDs) are now thought to be associated with infection of the gastric mucosa by the gram-negative bacilli Helicobacter pylori. The majority of NSAID-related ulcers are gastric. H. pylori have been associated with both duodenal and gastric ulcers. Eradication of H. pylori promotes healing and markedly decreases recurrence of both duodenal and gastric ulcers (AH Soll, JAMA, 275:622, 1996).

Itraconazole (Sporanox - Janssen), an oral antifungal triazole that has been available in the USA since 1992 for treatment of deep fungal infections (Medical Letter, 35:7, 1993), is now being marketed for treatment of dermatophyte infections of the toenails, with or without fingernail involvement.

Tuberculosis (TB) continues to be a major problem in the United States, particularly in areas where drug resistance is common (Morbid Mortal Weekly Rep, 44:387, May 26, 1995). Since poor compliance is the most important cause of treatment failure and is associated with emergence of drug resistence, some experts now recommend that all patients take drugs for TB under direct observation (SE Weis et al, N Engl J Med, 330:1179, 1994; R Bayer and D Wilkinson, Lancet, 345:1545, June 17, 1995).

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).

Moricizine (mor i'; siz een) hydrochloride (Ethmozine - Du Pont), a class I antiarrhythmic drug developed in the USSR, was recently approved by the US Food and Drug Administration (FDA) for oral treatment of life-threatening ventricular arrhythmias.

Adenosine (Adenocard - Fujisawa), an endogenous purine nucleoside, was recently approved by the US Food and Drug Administration for intravenous treatment of paroxysmal supraventricular tachycardia, including Wolff-Parkinson-White (WPW) syndrome. Adenosine is not approved for and has not been effective in treating atrial flutter, atrial fibrillation, or ventricular tachycardias.

Propafenone (Rythmol - Knoll), a class IC antiarrhythmic drug used in Europe for treatment of various arrhythmias for more than 10 years, was recently marketed in the USA for oral treatment of life-threatening ventricular arrhythmias such as sustained ventricular tachycardia. This restrictive labeling reflects concerns arising from the interim report of the Cardiac Arrhythmia Suppression Trial, in which post-myocardial infarction patients with asymptomatic or mildly symptomatic ventricular arrhythmias treated with the class IC antiarrhythmic drugs encainide (Enkaid) or flecainide (Tambocor) had a higher mortality rate than patients taking placebo (CAST, N Engl J Med, 321:406, 1989).

Mefloquine hydrochloride (Lariam - Roche), a new antimalarial drug chemically related to quinine, has been approved by the US Food and Drug Administration (FDA) for prevention and treatment of Plasmodium falciparum and P. vivax malaria.