The CDC has issued a recommendation for use of a single dose of doxycycline for post-exposure prophylaxis (PEP) of bacterial sexually transmitted infections (STIs), specifically syphilis, chlamydia, and gonorrhea, in men who have sex with men (MSM) and transgender women (TGW) who had a bacterial STI within the previous 12 months.

Since 2007, antimicrobial prophylaxis for dental procedures has been recommended to prevent viridans group streptococcal infective endocarditis only for patients at highest risk of an adverse outcome. Limiting use to such patients does not appear to have led to an increased incidence of infective endocarditis or increased mortality due to infective endocarditis.

Since 2007, antimicrobial prophylaxis for dental procedures has been recommended to prevent viridans group streptococcal infective endocarditis only for patients at highest risk of an adverse outcome. Limiting use to such patients does not appear to have led to an increased incidence of infective endocarditis or increased mortality due to infective endocarditis.

Acne is common among adolescents and adults. Guidelines for treatment of acne were last published by the American Academy of Dermatology in 2016.

Rosacea is a common, chronic inflammatory facial eruption of unknown cause. It is more prevalent in women than in men, and disease onset typically occurs after age 30. Rosacea is characterized by erythema, telangiectasia, and flushing, and sometimes by recurrent, progressive crops of acneiform papules and pustules, usually on the central part of the face. Some patients develop granulomas and tissue hypertrophy, which may lead to rhinophyma (a bulbous nose), particularly in men. Blepharitis and conjunctivitis are common. Keratitis and corneal scarring occur rarely.

Most respiratory tract infections are caused by viruses. Bacterial respiratory tract infections are usually treated empirically with antibiotic therapy that targets the most probable causative pathogens. Recommended antibiotic regimens for outpatient treatment of some common respiratory tract infections are listed in Table 1 for adults and Table 2 for children.

Epsolay (Galderma), a 5% benzoyl peroxide cream, has been approved by the FDA for treatment of inflammatory lesions of rosacea in adults. It is the first product containing benzoyl peroxide to be approved in the US for treatment of rosacea. Benzoyl peroxide formulations approved for acne have been used off-label to treat rosacea for years, but itching and burning have limited their use.

This article includes recommendations for management of most sexually transmitted infections (STIs) other than HIV and viral hepatitis. Some of the indications and dosages recommended here have not been approved by the FDA (see Table 1).

Lyme disease in the US is caused by the spirochete Borrelia burgdorferi, which is transmitted to humans by Ixodes scapularis (blacklegged [deer] tick) and I. pacificus (western blacklegged tick). Most cases of Lyme disease occur in late spring and early summer in northeastern and mid-Atlantic states, the upper Midwest, and in northern California. B. mayonii, which is also transmitted by I. scapularis, has been shown to cause a similar illness in the upper Midwest.

The CDC has issued new recommendations for treatment of gonococcal infection. A single 500-mg IM dose (1000 mg in patients weighing ≥150 kg) of the third-generation cephalosporin ceftriaxone is now the treatment of choice for patients with uncomplicated urogenital, rectal, or pharyngeal gonorrhea.

Treatment of community-acquired pneumonia (CAP) is usually empiric, with selected antibiotic regimens directed against some of the most common causative pathogens. Recommended empiric regimens are listed in Table 2; recommended antibiotic dosages for treatment of CAP are listed in Tables 3 and 4. Joint guidelines for treatment of CAP by the American Thoracic Society and the Infectious Diseases Society of America (ATS/IDSA) were updated in 2019.

Acne is common among adolescents and young adults, but its prevalence appears to have increased in people of all ages due to prolonged wearing of masks during the COVID-19 pandemic. Guidelines for treatment of acne were last published in 2016.

The FDA has approved a 1.5% topical foam formulation of minocycline (Zilxi – Foamix) for treatment of inflammatory lesions of rosacea in adults. It is the only topical minocycline product approved for this indication. The same manufacturer markets minocycline foam 4% (Amzeeq) for treatment of acne in patients ≥9 years old.

Artesunate for injection (Amivas LLC), a semi-synthetic artemisinin derivative, is now approved by the FDA for initial (induction) treatment of severe malaria in children and adults. It has been available from the CDC on a compassionate use basis since 2007. Artemether/lumefantrine (Coartem), another artemisinin-based drug, was approved earlier for oral treatment of uncomplicated Plasmodium falciparum malaria. IV artesunate is now the only FDA-approved injectable antimalarial drug available in the US; IV quinidine has been discontinued.

The FDA has approved a 4% aerosol foam formulation of minocycline (Amzeeq – Foamix) for topical treatment of inflammatory lesions of non-nodular moderate to severe acne in patients ≥9 years old. It is the first topical tetracycline formulation to be approved for use in patients with acne. Oral minocycline (Minocin, Solodyn, and generics) is

Patients who receive pretravel advice can reduce their risk for many travel-related conditions. Vaccines recommended for travelers are reviewed in a separate issue.

Lefamulin (Xenleta – Nabriva), a semisynthetic pleuromutilin antibiotic, has been approved by the FDA for IV and oral treatment of community-acquired bacterial pneumonia (CABP) in adults. It is the first systemic pleuromutilin antibiotic to be approved in the US; retapamulin (Altabax), a 1% topical ointment for treatment of impetigo, was approved in 2007.

The oral antimalarial tafenoquine succinate, a long-acting analog of primaquine, has been approved by the FDA in 2 different strengths. Arakoda (100-mg tablets; Sixty Degrees) is indicated for the prophylaxis of malaria in adults. Krintafel (150-mg tablets; GSK) is indicated for the prevention of relapse (radical cure) of Plasmodium vivax malaria in patients ≥16 years old undergoing treatment for acute P. vivax infection.

View the Expanded Table: Drugs for Prophylaxis of Malaria

The FDA has approved omadacycline (Nuzyra – Paratek), a semisynthetic tetracycline derivative, for once-daily IV and oral treatment of community-acquired bacterial pneumonia (CAP) and acute bacterial skin and skin structure infections (ABSSSIs) in adults.

Sarecycline (Seysara — Allergan), a new oral tetracycline antibiotic, has been approved by the FDA for once-daily treatment of inflammatory lesions of non-nodular moderate to severe acne in patients ≥9 years old.

The FDA has warned that use of the macrolide antibiotic clarithromycin (Biaxin, and generics) may increase the risk of cardiovascular morbidity and mortality in patients with heart disease.

View the Comparison Table: Some Antibiotics for MRSA Skin and Skin Structure Infections

Bacterial infections in adults are generally treated empirically, with the antibiotic covering most, but not all, of the potential causative pathogens. For some infections, culture and sensitivity testing can guide treatment, allowing for use of narrower-spectrum antibiotics. The recommended dosages and durations of antibiotic treatment for common respiratory, skin, and urinary tract infections are listed in Tables 1-3. Infectious disease experts now recommend shorter treatment durations for many infections to reduce the development of antimicrobial resistance and minimize adverse effects.

About 50% of the world’s population is infected with Helicobacter pylori. These gastric bacteria can cause chronic inflammation and have been associated with development of gastritis, peptic ulcer disease, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Eradication of H. pylori can promote gastric healing, prevent recurrence of duodenal and gastric ulcers, and reduce the incidence of gastric cancer. Guidelines for treatment of H. pylori infection were updated recently.

The text and tables that follow include recommendations for management of sexually transmitted infections (STIs) other than HIV and viral hepatitis. Some of the indications and dosages recommended here have not been approved by the FDA.

The FDA has approved the selective alpha_1A-adrenergic receptor agonist oxymetazoline as a 1% cream (Rhofade – Allergan) for topical treatment of persistent facial erythema of rosacea in adults. Brimonidine, a selective alpha₂-adrenergic receptor agonist, was approved in 2013 as a 0.33% gel (Mirvaso) for the same indication. Like Mirvaso, Rhofade is not indicated for treatment of inflammatory lesions of rosacea. Oxymetazoline has been available over the counter for many years as a nasal decongestant spray (Afrin, and others).

A reader commenting on our Treatment of Lyme Disease article (Med Lett Drugs Ther 2016; 58:57) objected to a footnote in the table advising against use of doxycycline in children <8 years old. This warning has been included in the labeling of all tetracyclines since 1970 when it was recognized, after decades of use, that these drugs caused permanent staining and enamel hypoplasia of developing teeth. The CDC recently stated that short courses of doxycycline, which was first marketed in the US in 1967 and has less affnity for calcium than other tetracyclines, have not been shown to cause tooth staining.1 That statement was prompted by the discovery that children <10 years old have a disproportionately high fatality rate from rickettsial diseases, particularly Rocky Mountain spotted fever, for which doxycycline is the drug of choice and chloramphenicol is the only proven alternative.

The main evidence supporting the CDC's statement was a retrospective cohort study consisting of a record review and dental examination of 271 children living on a Native American reservation. No staining was detected in any of the 58 children who had been treated with doxycycline before the age of 8 years or in any of the 213 children who had not been exposed to the drug. Enamel hypoplasia was present in 4% of children in both cohorts.2

Lyme disease, unlike Rocky Mountain spotted fever, is seldom fatal and can be treated with antibiotics other than doxycycline. A single dose of doxycycline is recommended for prophylaxis after a tick bite. Given the CDC's statement about its safety, it would seem reasonable to use doxycycline for prophylaxis in all age groups. When longer treatment courses (10, 14, or 28 days) are recommended for the various clinical manifestations of Lyme disease in children <8 years old, alternative antibiotics generally could be used instead.

1. HM Biggs et al. Diagnosis and management of tickborne rickettsial diseases: Rocky Mountain spotted fever and other spotted fever group Rickettsioses, Ehrlichioses, and Anaplasmosis – United States. MMWR Recomm Rep 2016; 65:1.
2. SR Todd et al. No visible dental staining in children treated with doxycycline for suspected Rocky Mountain spotted fever. J Pediatr 2015; 166:1246.

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The FDA has announced that it is requiring changes in the labeling of systemic fluoroquinolones to warn that the risk of serious adverse effects, including tendinitis, peripheral neuropathy and CNS effects, generally outweighs their benefit for the treatment of acute sinusitis, acute exacerbations of chronic bronchitis, and uncomplicated urinary tract infections. For these infections, the new labels will recommend reserving fluoroquinolones for patients with no other treatment options.

Antimicrobial prophylaxis can decrease the incidence of postoperative surgical site infection after some procedures. Since the last Medical Letter article on this subject, consensus guidelines have been published. Recommendations for prophylaxis in specific surgical procedures are listed in Table 1.

Most cases of Lyme disease in the US occur between May and September in the Northeastern, Mid-Atlantic, and North Central states.

The pathogenesis of acne is multifactorial: follicular hyperkeratinization, bacteria, sebum production, androgens, and inflammation all play a role. The gram-positive microaerophilic bacteria Propionibacterium acnes promotes development of acne lesions by secreting chemotactic factors that attract leukocytes to the follicle, causing inflammation.

This common, chronic inflammatory facial eruption of unknown cause is more prevalent in women than in men. Rosacea is characterized by erythema and telangiectasia, and sometimes by recurrent, progressive crops of acneiform papules and pustules, usually on the central part of the face. Some patients develop granulomas and tissue hypertrophy, which may lead to rhinophyma (a bulbous nose), particularly in men. Blepharitis and conjunctivitis are common. Keratitis and corneal scarring occur rarely.

The FDA has approved a 1% cream formulation of the antiparasitic drug ivermectin (Soolantra – Galderma) for topical treatment of inflammatory lesions of rosacea. Ivermectin is available in the US in tablets (Stromectol, and generics) for treatment of onchocerciasis and other worm infestations and as a 0.5% lotion (Sklice) for treatment of head lice.

Patients planning to travel to other countries often ask for information about prevention of diarrhea, malaria, and other travel-related conditions. Vaccines recommended for travelers based on their destination, length of stay, and planned activities were reviewed in a previous issue.

The FDA has approved oritavancin (Orbactiv – The Medicines Company), a long-acting lipoglycopeptide antibiotic given as a single intravenous (IV) dose, for treatment of acute bacterial skin and skin structure infections caused by susceptible gram-positive bacteria in adults. It is the third lipoglycopeptide antibiotic to be marketed in the US; telavancin (Vibativ) and dalbavancin (Dalvance) were approved earlier.

Most patients with end-stage renal disease develop hyperphosphatemia, which can lead to secondary hyperparathyroidism, vascular calcification, and cardiovascular mortality. The FDA has approved sucroferric oxyhydroxide (Velphoro – Fresenius Medical Care), a chewable phosphate binder, for treatment of hyperphosphatemia in patients with chronic kidney disease (CKD) on dialysis. It is the first iron-based phosphate binder to be approved for this indication.

Methicillin-resistant Staphylococcus aureus (MRSA), which was traditionally a nosocomially-acquired organism but now frequently occurs in the absence of healthcare exposure, is the predominant cause of suppurative skin and soft-tissue infections in many parts of the US. Community-associated MRSA usually causes furunculosis, purulent cellulitis, and abscesses, but necrotizing fasciitis, necrotizing pneumonia, and sepsis can also occur.

Many infections can be transmitted during sexual contact. The text and tables that follow include recommendations for management of sexually transmitted infections (STIs) other than HIV, viral hepatitis, and enteric infections. Some of the indications and dosages recommended here have not been approved by the FDA.

The text that follows reviews some common bacterial infections and their empiric treatment pending the results of culture and susceptibility testing. The recommendations made here are based on the results of susceptibility studies, clinical trials, and the opinions of Medical Letter reviewers. Tables 1 and 2 list the usual dosages of antibacterial drugs.

The FDA has approved raxibacumab (rax” ee bak’ ue mab; GSK), a fully human monoclonal antibody given by intravenous infusion, for treatment of inhalational anthrax in combination with appropriate antibacterial drugs, and for prophylaxis of inhalational anthrax when alternative therapies are not available or are not appropriate. It was approved under the Animal Efficacy Rule, which allows the FDA to approve drugs that demonstrate efficacy in animals, providing that they would have a reasonable human health benefit and are safe for human use. Raxibacumab is only available from the CDC.

The pathogenesis of acne is multifactorial: follicular hyperkeratinization, bacteria, sebum production, androgens, and inflammation all play a role. The gram-positive microaerophilic bacteria Propionibacterium acnes promote development of acne lesions by secreting chemotactic factors that attract leukocytes to the follicle, causing inflammation.

Antimicrobial prophylaxis can decrease the incidence of postoperative infection, particularly surgical site infection, after some procedures. Recommendations for such prophylaxis are listed in the table that begins on page 74. Antimicrobial prophylaxis for dental procedures to prevent endocarditis was recently discussed in The Medical Letter.

Patients planning to travel to other countries often ask for information about appropriate vaccines and prevention of diarrhea and malaria. More detailed advice for travelers is available from the Centers for Disease Control and Prevention (CDC) at www.cdc.gov/travel. Guidelines are also available from the Infectious Diseases Society of America (IDSA).

Most cases of Lyme disease in the US occur between May and September in the Northeastern, Mid-Atlantic and North Central states.

Many infections can be transmitted during sexual contact. The text and tables that follow are limited to management of sexually transmitted infections (STIs) other than HIV, viral hepatitis and enteric infections. The drugs of choice, their dosages and alternatives are listed in a table that begins on page 54. A table listing the adverse effects of some of these antimicrobials begins on page 58.

The text below reviews some common bacterial infections and their treatment. The recommendations made here are based on the results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants.

Patients planning to travel to other countries often ask physicians for information about appropriate vaccines and prevention of diarrhea and malaria. Guidelines are also available from the Infectious Diseases Society of America (IDSA).

Antimicrobial prophylaxis can decrease the incidence of infection, particularly surgical site infection, after certain procedures. Recommendations for prevention of surgical site infection are listed in the table that begins on page 48. Antimicrobial prophylaxis for dental procedures to prevent endocarditis is discussed in The Medical Letter 2007; 49:99.

The pathogenesis of acne is multifactorial: follicular hyperkeratinization, bacteria, sebum production, androgens and inflammation all play a role. The gram-positive microaerophilic bacteria Propionibacterium acnes promote development of acne lesions by secreting chemotactic factors that attract leukocytes to the follicle, causing inflammation.

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.

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Many infections can be transmitted during sexual contact. The text and tables that follow are limited to management of sexually transmitted infections (STIs) other than HIV, viral hepatitis and enteric infections. Guidelines are available from the US Centers for Disease Control and Prevention (CDC) with detailed recommendations for treatment of these diseases.

Most cases of Lyme disease in North America occur between May and September. In 2005, 12 states (CT, DE, ME, MD, MA, MI, NH, NJ, NY, PA, VA, WI) reported about 95% of all the Lyme disease in the US, but some cases occurred in all states except AR, CO, HI, MS, MT and OK. New guidelines for treatment of Lyme disease have been published.

Information about empirical treatment of bacterial infections, emerging trends in antimicrobial resistance, new drugs and new data about older drugs continue to become available. Usual pathogens and empiric treatment for some common types of infections are summarized in the text and a table listing the drugs of choice and alternatives for each pathogen begins on page 40. The recommendations made here are based on the results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants.

A new once-daily, low-dose oral formulation of doxycycline monohydrate (Oracea - CollaGenex) has been approved by the FDA for treatment of inflammatory papules and pustules associated with rosacea in adults.

Antimicrobial prophylaxis can decrease the incidence of infection, particularly surgical site infection, after certain procedures. Recommendations for prevention of surgical site infection are listed in this article.

The FDA has approved an extended-release formulation of minocycline (Solodyn - Medicis) for once-daily treatment of non-nodular moderate to severe acne.

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.

Methicillin-resistant Staphylococcus aureus (MRSA) infections, which have been a concern for many years, previously occurred primarily in hospitalized patients and those recently treated with antibiotics. In the past few years, there has been an increasing incidence worldwide of community-associated (CA) MRSA infections in patients without recent antibiotic exposure or contact with the healthcare system.

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.

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The pathogenesis of acne is multifactorial: follicular hyperkeratinization, Propionibacterium acnes bacteria, sebum production, androgens and inflammation have all been implicated. P. acnes, a gram-positive microaerophilic bacterium, plays an important role in the development of acne lesions by secreting chemotactic factors that attract leukocytes to the follicle, causing inflammation.

Lyme disease in North America is caused by the spirochete Borrelia burgdorferi, which is transmitted to humans by Ixodes scapularis or pacificus ticks. These ticks may also carry other pathogens; coinfection with Babesia microti or Anaplasma phagocytophilum (formerly Ehrlichia) has been reported.1 In 2001 and 2002, 12 states (CT, DE, ME, MD, MA, MI, NH, NJ, NY, PA, RI, WI) reported about 95% of all the Lyme disease in the US, but cases occurred in all states except HI, MT and OK. Most Lyme disease in North America occurs between May and September.

Many infections can be transmitted during sexual contact. The text and tables that follow are limited to management of sexually transmitted infections (STIs) other than HIV, viral hepatitis and enteric infections. Guidelines are available from the US Centers for Disease Control and Prevention (CDC) with detailed recommendations for treatment of these diseases (MMWR Recomm Rep 2002; 51, RR-6:1). New guidelines are expected soon.

Gemifloxacin (Factive - Oscient), a new oral fluoroquinolone antibiotic, has been approved by the FDA for 5 days' treatment of acute bacterial exacerbations of chronic bronchitis (ABECB) and 7 days' treatment of mild to moderate community-acquired pneumonia (CAP) in adults. For the next 6-8 months it will only be available, presumably for commercial reasons, in states east of the Rocky Mountains.

Telithromycin (Ketek - Aventis) has been approved by the FDA for oral treatment of mild to moderate community-acquired pneumonia, acute exacerbations of chronic bronchitis and acute bacterial sinusitis in patients age 18 and older. The drug is the first in a new class of antibiotics, the ketolides, derived from the macrolide erythromycin. Telithromycin has been marketed in Europe since 2001.

Parasitic infections are found throughout the world. With increasing travel, immigration, use of immunosuppressive drugs and the spread of AIDS, physicians anywhere may see infections caused by previously unfamiliar parasites. The table below lists first-choice and alternative drugs for most parasitic infections. The brand names and manufacturers of the drugs are listed in this article.

Patients planning to travel to other countries often ask physicians for advice about immunizations and prevention of diarrhea and malaria. More detailed advice for travelers is available from the Centers for Disease Control (CDC) at 877-FYI-TRIP (877-394-8747) or www.cdc.gov/travel. Recommendations for the treatment of parasitic diseases are available in the public reading room of The Medical Letter's web site.

Antimicrobial prophylaxis can decrease the incidence of infection, particularly surgical site infection, after certain operations, but this benefit must be weighed against the risks of toxic and allergic reactions, emergence of resistant bacteria, adverse drug interactions, superinfection and cost. Medical Letter consultants generally recommend antimicrobial prophylaxis only for procedures with high infection rates, those involving implantation of prosthetic material, and those in which the consequences of infection are likely to be especially serious.

New drugs for bacterial infections and new information about older drugs continue to become available. Empirical treatment of some common bacterial infections is discussed in this article. A table listing the drugs of choice and alternatives for each pathogen begins on page 18. These recommendations are based on results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants. Local resistance patterns should be taken into account. Trade names are listed on page 24.

The choice of drugs for treatment of pneumonia depends on the most likely pathogens causing the infection and local antimicrobial resistance patterns. Factors such as severity of illness, presence of co-morbid conditions and whether the infection is community or hospital-acquired also need to be considered.

Augmentin XR (GlaxoSmithKline), an oral extended-release combination of amoxicillin and the beta-lactamase inhibitor clavulanic acid, is now being promoted for treatment of acute bacterial sinusitis and community-acquired pneumonia. Augmentin XR contains a higher dose of amoxicillin than Augmentin.

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

Superseded--purchase updated Parasitic Infections article
Parasitic infections are found throughout the world. With increasing travel, immigration, use of immunosuppressive drugs and the spread of AIDS, physicians anywhere may see infections caused by previously unfamiliar parasites.

Note: Drugs for Parasitic Infections, revised and updated, is now available to both subscribers and nonsubscribers on our web site. This article, a bi-annual feature of The Medical Letter for many years, will not be published as a printed issue in 2002, but is included in the 16th edition of The Medical Letter Handbook of Antimicrobial Therapy. The handbook is now available and can be ordered by calling customer service at 1-800-211-2769.

Superseded by Handbook of Antimicrobial Therapy
The Medical Letter article on Drugs and Vaccines against Biological Weapons, published in the previous issue (October 15, 2001, page 87), included a brief discussion of post-exposure prophylaxis of inhalation anthrax. Recent events call for more detail.

Concerns have arisen anew about possible use of biological weapons. The pathogens considered most likely to be used for this purpose are discussed in this article. A good source for additional information is www.usamriid.army.mil/education/bluebook.html.

A fixed-dose combination of atovaquone and proguanil hydrochloride has been approved by the FDA for oral prophylaxis and treatment of malaria due to Plasmodium falciparum, including choloroquine-resistant strains.

Lyme disease is caused by the spirochete Borrelia burgdorferi and transmitted to humans by Ixodes ticks. These ticks may also carry other pathogens; co-transmission of Babesia and Ehrlichia species has been reported.

Gatifloxacin and moxifloxacin are now available for once-daily treatment of patients with community-acquired pneumonia, acute bacterial exacerbations of chronic bronchitis, or acute sinusitis.

Patients planning to travel often ask for advice on prophylaxis against malaria. None of the antimalarials used in the past for prophylaxis has been entirely satisfactory.

Many infections can be transmitted during sexual contact. The text and tables [in this article] are limited to treatment of non-HIV infections associated primarily with sexual transmission.

Patients planning to travel to other countries often ask pysicians for advice about immunizations and prevention of diarrhea and malaria. Legal requirements for entry and epidemiological conditions in different countries vary from time to time, often unpredictably, but some reasonable recommendations can be made.

Concerns persist about the possible use of biological weapons. Among the many organisms found in nature that cause serious infections, only a few have the combination of pathogenicity, stability and ease of production needed to make effective biological warefare agents.

Cefdinir (Omnicef - Parke-Davis), a third-generation oral cephalosporin, has been approved by the FDA for treatment of acute sinusitis, otitis media, acute exacerbations of chronic bronchitis, pharyngitis, community-acquired pneumonia and skin infections. Other drugs available for these indications are reviewed in The Medical Letter Handbook of Antimicrobial Therapy, 1998.

Now that US Secretary of Defense has decided to vaccinate more than 2 million memebers of the US armed forces against anthrax, US physicians may be asked to answer some questions about the vaccine and the disease.

(Superseded by the 2013 version. Click here to purchase.)
Parasitic infections are found throughout the world. With increasing travel, immigration, use of immunosuppressive drugs and the spread of AIDS, physicians anywhere may see infections caused by previously unfamiliar parasites. The table lists first-choice and alternative drugs for most parasitic infections.

Lyme disease, a multisystem infection transmitted by ixodid ticks and caused by the spirochete Borrelia burgdorferi is the most common vector-borne illness in the USA. Cases have been reported in 44 states, and also in Canada and many countries in Europe and Asia (ME Falagas and SL Gorbach, Infect Dis Clin Pract, 5:217, 1996).

Results of recently completed clinical trials have led to some changes in recommendation for treatment of human immunodeficiency virus (HIV) and other infections associated with AIDS.

Results of recently completed clinical trials have led to some changes in recommendations for treatment of human immunodeficiency virus (HIV) and other infections associted with AIDS.

Lyme disease, a multisystem infection transmitted by ixodid ticks and caused by the spirochete Borrelia burgdorferi the most common vector-borne illness in the USA. It occurs, mainly in the northeast, upper midwest, and California, but cases have been reported in 48 states, and also in Canada and many countries in Europe.

Clarithromycin (Biaxin - Abbott) and azithromycin (Zithromax - Pfizer), two macrolide antibiotics chemically related to erythromycin, have been approved by the US Food and Drug Administration for treatment of respiratory, skin, and skin structure infections. Azithromycin has also been approved for treatment of nongonococcal urethritis and cervicitis caused by Chlamydia trachomatis.

Patients planning to travel to other countries often ask physicians for advice about immunizations and prevention of diarrhea and malaria. Legal requirements for entry and epidemiological conditions in different countries vary from time to time, often unpredictably, but some reasonable recommendations can be made. More detailed information is available in Health Information for International Travel, published annually by the Centers for Disease Control (CDC), which can be obtained from the Superintendent of Documents, US Government Printing Office, Washington, DC 20402. Up-to-date automated information is available by telephone from the CDC (404-332-4559).

Almost 300,000 cases of epidemic cholera have occurred in the Western Hemisphere in 1991, mostly in South and Central America (Morbid Mortal Weekly Rep, 40:562, Aug 16, 1991). The few US cases caused by the epidemic strain have been in returning travelers or associated with contaminated food they brought back illicitly, with no secondary spread to date.

A growing number of clinical trials now permits some consensus on the treatment of human immunodeficiency virus (HIV) and other infections associated with acquired immune deficiency syndrome (AIDS) in adults.

With the deployment of hundreds of thousands of troops in Saudi Arabia, health problems endemic to the Arabian Peninsula may be coming to the attention of physicians in the USA and other areas.

Lyme disease, a multisystem bacterial transmitted by Ixodid ticks, particularly in early summer, continues to be a common problem in the USA and many other countries. Since last year (Medical Letter, 30:65, 1988), some new information has become available, but data on the choice, dosage and duration of antibiotic therapy are still available, but data on the choice, dosage and duration of antibiotic therapy are still limited.

Lyme Disease, a multisystem inflammatory disorder transmitted by lxodid ticks and caused by the spirochete Borrelia burgdorferi, is now the most common tick-transmitted illness in the USA. It has been reported in 32 states and on all other continents except Antarctica. Infected ticks have been found not only in wooded areas, but also on well-maintained suburban lawns (RC Falco and D Fish, Am J Epidemiol, 127:826, April 1988). Optimal treatment for this newly discovered disease is still being determined, but some recommendations based on published experience and work in progress can be made.