THURSDAY, Nov. 15 (HealthDay News) -- Experts on Thursday issued new clinical standards for the treatment of cystic fibrosis (CF).

The guidelines were based on a two-year review of published research on patients aged six and older.

"Physicians treating patients with CF are faced with a growing number of treatment options. We are hopeful that clinicians will find these recommendations to be useful in their care of patients with CF," the guidelines' lead author, Dr. Patrick A. Flume, said in a prepared statement.

CF is a genetic disease that affects the lungs and other organs. It's characterized by thick, sticky mucus that makes it almost impossible for CF patients to fight off germs and infections. The disease is always fatal, and lung disease accounts for 85 percent of deaths among CF patients. However, advances in treatment in the last 60 years have increased life expectancy from just a few years to about 36 years.

Flume and his colleagues looked at a number of treatments and rated their effectiveness. Those with the strongest, most consistent results were given an "A" grade recommendation. They are:

• Inhaled tobramycin -- an antibiotic -- to suppress chronic Pseudomonas aeruginosa infections in CF patients with moderate to severe disease, to improve lung function and reduce exacerbations.
• Dornase alfa, which degrades the free DNA that accumulates in CF mucus, thereby loosening the mucus, promoting airway clearance, improving lung function and reducing exacerbations.

"B" grade recommendations were given for:

• Inhaled tobramycin, to suppress Pseudomonas aeruginosa infections in CF patients with mild disease or who are asymptomatic, to reduce exacerbations.
• Dornase alfa, for CF patients with mild disease who are asymptomatic, to improve lung function and reduce exacerbations.
• Hypertonic saline, which hydrates surface liquid in patients with CF, thereby improving lung function and decreasing exacerbations.
• Beta 2-adrenergic receptor agonists, which relax smooth muscles and dilate bronchial passages, which improve lung function in CF patients, and are well-tolerated.

The guidelines recommend against:

• Systemic corticosteroids in children because of "an excess number of adverse events," including abnormalities in glucose metabolism, cataracts, and percentage of patients "colonized" with Pseudomonas. This recommendation excludes patients with concomitant asthma.
• Inhaled corticosteroids, because there's no clinical benefit. This recommendation excludes patients who also have asthma, however.
• Prophylactic anti-Staphylococcal antibiotics because of the lack of clinical efficacy and an apparent increase in P. aeruginosa infections with their use.

There wasn't sufficient evidence to recommend for or against other types of treatment, said Flume and his colleagues.

The guidelines are published in the second issue for November of the American Journal of Respiratory and Critical Care Medicine.

More information

The March of Dimes has more about cystic fibrosis.