Our article on Antiviral Drugs for Prophylaxis and Treatment of Influenza (Med Lett Drugs Ther 2005;47:93) mentioned possible use of amantadine (Symmetrel, and others) and rimantadine (Flumadine, and others), but warned that the incidence of resistance has increased substantially. The CDC recently issued a Health Alert (www.cdc.gov) saying that current evidence indicates that a high proportion of circulating influenza A viruses in the US are now resistant to amantadine and rimantadine and they should not be used for this indication, at least this year. Click here to go to this update...

Rimantadine hydrochloride (Flumadine - Forest), the alpha-methyl derivative of amantadine (Symmetrel, and others), was recently approved by the US Food and Drug Administration for prevention and treatment of influenza A virus infections in adults and for prevention of influenza in children.

Zanamivir, a neuraminidase inhibitor taken by inhalation, has been approved by the FDA for treatment of influenza. Oseltamivir phosphate, an oral neuraminidase inhibitor, will probably be approved soon.

Since publication of our recent article on antiviral drugs for influenza, increased levels of resistance to oseltamivir (Tamiflu) have been detected in influenza A H1N1 strains.

FluMist (MedImmune), the first live-attenuated and first intranasally administered influenza vaccine, has been approved by the FDA to prevent influenza in healthy people 5-49 years old. Given as a nasal spray, it stimulates immunity by viral replication in the upper respiratory tract. This vaccine apparently will be advertised directly to the public as a "needle-free" alternative to intramuscular influenza vaccine.

Gamma hydroxybutyrate (GHB), a central-nervous-system depressant notorious for its use in "date rape", was approved by the FDA in 2002 as sodium oxybate (Xyrem - Jazz Pharmaceuticals) for oral treatment of cataplexy in patients with narcolepsy. Now it has also been approved for treatment of excessive daytime sleepiness (EDS) in these patients. Xyrem is a Schedule III controlled substance.

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.

For patients with diabetes poorly controlled with a single oral drug, addition of a second drug with a different mechanism can be helpful. A fixed-dose combination (Actoplus met - Takeda) of two widely used antihyperglycemic drugs, the thiazolidinedione pioglitazone (Actos) and the biguanide metformin (Glucophage, and others), has been approved by the FDA for management of type 2 diabetes. It is indicated for patients already being treated with both pioglitazone and metformin or as second-line therapy for those not adequately controlled with either metformin or pioglitazone alone....

The drugs of choice for treatment of viral infections (other than HIV) and their dosages are listed in Tables 1-6 on the pages that follow. Some of the indications and dosages recommended here have not been approved by the FDA. Vaccines used for the prevention of viral infections are discussed elsewhere.