Prescription Medications May Do Little to Encourage CPAP Use

Obstructive sleep apnea (OSA) afflicts at least 2 to 4% of the adult population. The standard of treatment is either continuous or bilevel positive airway pressure (CPAP or BiPAP), according to the American Academy of Sleep Medicine’s 2006 practice parameters (see sidebar).

Positive airway pressure is a unique treatment option in that is has almost 100 percent efficacy under ideal circumstances, said Eric J. Kezirian, MD, MPH, Director of the Division of Sleep Surgery and Assistant Professor in the Department of Otolaryngology-Head and Neck Surgery at the University of California, San Francisco. Unfortunately, the effectiveness is limited by patient tolerance and adherence.

In studies, investigators have found that there are certain factors as to why patients do or do not tolerate positive airway pressure therapy, Dr. Kezirian continued. These factors can include, but are not limited to:

• Symptoms (people who are more tired may experience the largest improvement in energy levels after CPAP, and therefore have the strongest motivation).
• Anatomy (narrow nasal passages make nasal CPAP more difficult to tolerate).
• Personality (some people do not give up easily and will find a way to make CPAP more comfortable for themselves).
• Age (older adults tolerate CPAP better than younger adults).
• Technology (some devices are easier to wear; adding heated humidification will moisten the air and make CPAP more comfortable).

For some OSA patients, sleep medications can help those who are attempting to use CPAP or BiPAP overcome the initial difficulties in tolerating this treatment, when such difficulties exist, said Dr. Kezirian. They should be considered a temporary measure to help patients become accustomed to the device and promote long-term tolerance and adherence.

Sleep Meds and OSA Patients

A study published in the November 2006 issue of CHEST found that sleep medications might actually do little to help aid CPAP usage. Capt. David A. Bradshaw, MD, and his colleagues at the Naval Medical Center in San Diego hypothesized that giving an oral hypnotic medication to a group of male patients referred for CPAP treatment would help them to acclimate to CPAP and increase the number of hours they slept while using CPAP.

The researchers had previously discovered that, in a laboratory setting, a hypnotic medication often facilitates sleep during CPAP titration studies and that OSA patients who report significant insomnia are generally less tolerant of CPAP, but sometimes increase usage when provided a hypnotic medication.

In this study, all 72 patients (mean age 38 ± 7 years) participated in the standardized one-on-one CPAP training and were also randomized to receive zolpidem (10 mg), a placebo pill, or neither (standard care) for the first 14 days of CPAP treatment. Zolpidem is a relatively short-acting (half-life 1.5 to 2.4 hours) nonbenzodiazepine (imidazopyridine) hypnotic agent widely used for the treatment of insomnia. Patients taking zolpidem or a placebo were instructed to take one pill each night, 30 minutes before bedtime.

CPAP usage (effective mask pressure based on hours per day) was recorded by an internal data chip during the four-week trial. Patient symptoms were assessed with the Epworth Sleepiness Scale (ESS) and Functional Outcomes of Sleep Questionnaire (FOSQ). Treatment groups were matched for age, body mass index, and baseline ESS and FOSQ scores.

Despite randomization, the standard care group had a significantly higher apnea-hypopnea index (AHI) than either the zolpidem or placebo pill groups. Compared with the placebo pill and standard care groups, the zolpidem group did not show greater CPAP usage in terms of total days used or average time used per night. When the initial 14 days of CPAP treatment were analyzed separately, there was also no difference in the number of days used or average nightly use. Although average nightly CPAP usage within the zolpidem group was higher in the initial 14 days than in the subsequent 14 days, this did not reach statistical significance. There was also no difference across the three groups in the number of regular users, or patients who used CPAP on at least 70% of nights and averaged at least four hours per night.

Although all three CPAP treatment groups showed significant symptom improvement, as measured by the ESS and FOSQ, an oral hypnotic agent did not increase initial CPAP compliance in new users and Dr. Bradshaw and his fellow authors could not recommend empiric treatment.

OSA Insomnia Patients

However, since studies have shown that almost half of patients with OSA have insomnia complaints, the researchers believe prescription sleep medications, when used correctly, may prove helpful for a subset of patients with OSA insomnia.

Insomnia is the most common sleep disorder and there is a complex relationship between insomnia and OSA, said Dr. Kezirian. Sometimes, OSA contributes to insomnia and treating OSA can improve sleep patterns, whereas other times, the effective treatment of OSA may actually worsen insomnia because the sleepiness associated with OSA overcomes the tendency to remain awake in bed without sleeping.

In general, sleep medications are not the best first-line treatment for OSA patients with insomnia, Dr. Kezirian added. These patients should receive treatment for both disorders. Sleep medications can be part of a treatment plan for insomnia, but these patients should not receive sleep medications without treatment of OSA because the medications can actually worsen breathing patterns during sleep. In some cases, effective treatment of OSA alone can eliminate or at least simplify the treatment of insomnia because it eliminates the confounding effect of one disorder on another.

This study provides evidence that, contrary to popular practice, prescription medications that help patients to fall sleep may not improve compliance with nocturnal CPAP and possibly other devices used in the treatment of OSA, said Mark J. Rosen, MD, Chief of the Divisions of Pulmonary, Critical Care and Sleep Medicine at North Shore University Hospital and Long Island Jewish Medical Center in New York. Of course, it should be confirmed by larger studies, and perhaps using different drugs to validate this finding, to see if it is true across all of these medications.

Careful questioning about why a patient is unable to use CPAP can help you to identify other potential treatments to improve CPAP tolerance, said Dr. Kezirian. These may include behavioral measures (weight loss, lateral versus supine sleep position, no alcohol or sedatives at nighttime), surgery or oral appliances.

There are many factors to consider when determining the best treatment for OSA, added Dr. Kezirian. OSA severity and patient-related matters, such as age, medical problems, anatomy and utilization all enter into a patient’s decision to proceed with a specific, effective treatment plan.

Practice Parameters for Using CPAP and BiPAP

• A diagnosis of OSA must be established by an acceptable method.
• CPAP is effective for treating OSA.
• Full-night, attended studies performed in the laboratory are the preferred approach for titration to determine optimal pressure; however, split-night, diagnostic-titration studies are usually adequate.
• CPAP usage should be monitored objectively to help assure utilization.
• Initial CPAP follow-up is recommended during the first few weeks to establish utilization pattern and provide remediation, if needed.
• Longer-term follow-up is recommended yearly or as needed to address mask, machine or usage problems.
• Heated humidification and systematic educational programs are recommended to improve CPAP utilization.
• Some functional outcomes, such as subjective sleepiness, improve with positive pressure treatment in patients with OSA.
• CPAP and BiPAP therapy are safe; side effects and adverse events are mainly minor and reversible.
• BiPAP may be useful in treating some forms of restrictive lung disease or hypoventilation syndromes associated with hypercapnia.

Source: American Academy of Sleep Medicine. www.aasmnet.org /PDF/PP_PostiveAirwayPressure.pdf

©2007 The Triological Society