Drug Topics- August 11, 2008

53 not produce complete immunity, thus allowing for multiple yearly infections. Recent studies also suggest that the elderly adult populations may be another population at risk for RSV complications. RSV bronchiolitis will usually resolve in eight to 15 days, and management is mainly supportive and includes antipyretics for fever, increased fluid intake, and saline nasal sprays. Bronchodilators have shown some effectiveness and may be prescribed. For high-risk patients or severe cases, hospital admission may be required. Ribavirin, in aerosol form, is the only approved antiviral for RSV and is approved for use in infants. However, there have been anecdotal reports of use of ribavirin in adults. Ribavirin belongs to pregnancy category “x”, thus pregnant women or those women who are not on reliable birth control as well as their male partners should not be exposed to it. Controversy exists over the effectiveness of ribavirin as studies have not shown significant benefit. Co-infection with bacteria occurs in 10%-30% of patients already infected with RSV. A chest X-ray and sputum cultures can be used to confirm co-infection. Treatment with the specific antibiotic necessary to cover the bacterial infection is appropriate in co-infected patients. Palivizumab (Synagis) and RSV immune globulin [RSV-IG] (Respigam) may be used for prophylaxis of RSV bronchiolitis in certain high-risk patient populations, but they are not indicated for treatment. Bronchitis The hallmark sign of bronchitis is cough. Bronchitis is classified as acute or chronic. Patients with chronic bronchitis can have acute exacerbations (AECB). Acute bronchitis has a more sudden onset and is commonly seen in otherwise healthy patients. In contrast, chronic bronchitis is part of chronic obstructive pulmonary disease (COPD) and usually develops due to longstanding lung insults, such as smoking or environmental factors. For ease of reading, acute bronchitis and AECB will be discussed separately. Acute bronchitis is one of the most common diagnoses and is reported in 5% of the general population annually. Acute bronchitis is a poorly defined upper respiratory infection and may resemble several other respiratory infections and disorders, including acute asthma, pneumonia, severe acute respiratory syndrome (SARS), and the common cold. Differential diagnosis is essential. Acute bronchitis has two phases. In the first phase, patients will have nonspecific symptoms such as fever, malaise, and myalgias. These symptoms last from one to five days. The second phase, lasting one to three weeks, consists of one or more of the following: persistent cough, phlegm production, or wheezing. Airway hypersensitivity and decreased pulmonary function tests (PFTs), resembling acute asthma, are also seen during the second phase. However, unlike asthma, PFTs will usually resolve in two to three weeks. Unlike pneumonia, vital signs will be fairly normal and chest X-rays will be clear in acute bronchitis. The ACCP does not recommend routine chest Xrays if acute bronchitis is suspected. Acute bronchitis is most commonly caused by viral pathogens. The most common viruses suspected in acute bronchitis, in order of prevalence, include influenza A and B, parainfluenza, RSV, coronavirus, adenovirus, and rhinoviruses. Human metapneumovirus (hMPV) is an emerging pathogen suspected in acute bronchitis, especially among immunocompromised patients. Bacteria cause less than 10% of acute bronchitis. Mycoplasma pneumoniae, Chlamydia pneumoniae, and Bordetella pertussis have been established as bacterial causes of acute bronchitis. Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis have been suspected but have not been proven to cause acute bronchitis. Patients with bacterial infections may have longer duration of symptoms and are more likely to present with wheezing than those with viral infections. The most effective treatment of acute bronchitis is prevention. Methods to avoid acute bronchitis are: frequent hand washing, avoiding infected individuals, and updated vaccinations, especially pertussis and influenza. If a patient does develop acute bronchitis, treatment is mostly supportive. If infection with influenza is suspected or confirmed within 48 hours of onset of symptoms, treatment with antivirals such as amantadine, rimantadine, zanamivir (Relenza), or oseltamivir (Tamiflu) may be used. Amantadine and rimantidine are only effective against influenza A while zanamivir and oseltamivir are effective against both A and B strains. Studies have shown that treatment with antivirals decreases duration of illness by one day and may lead to a return to normal level of activity by half a day. Although antibiotics are frequently prescribed, studies have shown they are not effective for almost all cases of acute bronchitis, and ACCP guidelines recommend against prescribing antibiotics for routine treatment. The exception is acute bronchitis caused by B. pertussis. These patients will usually present with paroxysmal cough or “whooping” cough along with choking or vomiting. These patients need to be treated within seven to 10 days of onset of symptoms with either erythromycin 250mg four times a day or 333mg three times a day for seven to 10 days. Trimethoprim/sulfamethoxazole can be used as an alternative if a patient is allergic to macrolides. The use of bronchodilators, such as albuterol, is not recommended in most cases of acute bronchitis. A recent large review of studies of bronchodilators for acute bronchitis showed these agents failed to reduce cough severity or duration. Additionally, side effects, such as tremors, tachycardia, and nervousness, were prevalent. However, ACCP guidelines do recommend using bronchodilators—specifically, beta agonists—in patients with acute bronchitis accompanied with significant wheezing. Antitussives, such as codeine and dextramethorphan, have been shown to be useful to control severe coughing associated with acute bronchitis, and ACCP recommends the occasional short-term use of these agents. Studies have failed to show benefit of using mucokinetic agents, such as guaifenisin in acute bronchitis, and therefore these agents should be avoided.

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Drug Topics- August 11, 2008 Contents Latebreakers Letters DEA Proposes Rule To Allow Electronic Prescriptions for Controlled Substances Merger, Medicare Reform Could Mean Broader E-Prescribing Adoption New Combination Pill Approved for Type 2 Diabetes New Eczema Guildlines Promote Use of Emollients, Then Topical Corticosteroids Agencies Flush Original Strategies in Favor of Promoting Drug Take-Back Programs JP at Large: You Laughing at Me? Pharmacists Find Themselves at Mercy of Prior Authorization State Law Requiring PBM Transparency See Some Gains, Some Losses Global Counterfeiting Still Growing, Says U.S. Commerce Official FDA Saftey Page: Prophylthiouracil Still Confused with Purinethol (mercaptopurine) New Products Bring Lice Treatment to a Head NACDS Marketplace Showcases New Product that Fill Unmet Needs Update on Respiratory Tract Infections Execs Share War Stories About Adopting Technology in their Stores New Products Advertisters Index Classified Viewpoint: Medicare Part D Revisions sorely needed

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