Acetylcysteine can also be given as an antidote to protect the liver from a potentially toxic overdose of acetaminophen. It must be given within 24 hours of the ingestion. A loading dose is administered orally and is followed by 17 maintenance doses q4.
- recombinant human deoxyribonuclease, dornase alpha, rhDNase (Pulmozyme): Classified as an orphan drug, dornase alpha breaks down the DNA molecules of thick, viscid airway mucus. It is helpful in the management of cystic fibrosis by reducing the viscosity of secretions, improving airway clearance, thereby decreasing the frequency and severity of pulmonary infections. The drug is available as a single dose ampule containing 2.5 mg of the drug. It must be delivered by a nebulizer system capable of producing the correct particle size and quantity and should not be mixed with other medications. Ampules of the drug must be protected from light and stored under refrigeration (or ice chest when traveling). Adverse effects of the drug are usually minimal but may include voice alteration, pharyngitis, laryngitis, rash, chest pain, and conjunctivitis. Rarely cough increase, dyspnea, "flu" syndrome, and malaise have been reported.
- gentamicin (Garamycin): Because the airways of patients with cystic fibrosis are chronically colonized or infected with gram-negative organisms such as Pseudomonas aeruginosa, antibiotics, especially those with poor lung tissue availability with oral administration, are sometimes aerosolized to deliver the drug directly to the site of infection. Gentamicin is aminoglycoside antibiotic that is sometimes used to control gram-negative organisms in an attempt to prevent deterioration of lung function. There is no specific recommended aerosol dose although 20 mg bid has been used in some studies. The aerosolized drug may cause airway irritation resulting in cough or bronchospasm. Pretreatment with a bronchodilator may be necessary if pre- and post- gentamicin changes in flow rates are measured. The respiratory care practitioner should be aware that the function of the nebulizer may be altered because of the increased viscosity of the drug solution. Containment of the drug by the appropriate filtered nebulizer system or negative pressure chamber is recommended to protect the practitioner from inhaling the drug and to prevent environmental contamination.
- tobramycin for inhalation (TOBI) Tobramycin is an aminoglycoside antibiotic indicated for the management of Pseudomonas aeruginosa infection in cystic fibrosis patients. Clinical research data collected over six months demonstrated that patients who received aerosolized tobramycin, had improved lung function, fewer hospital days, and required fewer days of anti-pseudomonal antibiotic therapy. TOBI is packaged in 5 ml ampules, each containing 300 mg of tobramycin. Each box of TOBI contains 56 ampules packaged in 14 foil pouches. The drug should be stored in the refrigerator although the foil pouches may be kept at room temperature (up to 77 degrees for 28 days). The drug may darken slightly but is still usable up to 28 days. TOBI should be administered by a special nebulizer (PARI LC PLUSTM) powered by a Pulmo-AideTM compressor and should not be mixed with other drugs. It should be given following the administration of any other nebulized drugs. The recommended regimen is 300 mg (1 ampule) bid with treatments as close to 12 hours apart as possible. The patient should continue the drug for a 28 day cycle and then is off the drug for 28 days. The safety and dosage of TOBI has not been evaluated for patients less than six years of age. Bronchospasm can occur with the inhalation of tobramycin and should be treated appropriately. The most common adverse effects of TOBI administration are voice alteration (13% vs 7% placebo) and transient tinnitus (3% vs 0% placebo).
- albuterol (Ventolin, Proventil): Albuterol is a beta-2 selective adrenergic bronchodilator. Since there is an increased incidence of asthma among cystic fibrosis patients, albuterol (and similar beta-2 agonists) may be helpful in the management of obstructive symptoms. Ventolin is available as a metered dose inhaler, dry powder inhaler, tablets, extended- release tablets, and as a syrup. Proventil is a 0.5% solution for nebulization. The drug reaches a peak effect in 30 to 60 minutes and has an approximate duration of up to 6 hours. Recommended adult aerosol dosages are as follows:
Nebulizer 0.5 ml (in 3-5 ml NS) TID or QID MDI 2 puffs, tid or qid
The most common side effect is tremor. In higher dosages, the drug becomes less beta-2 specific and beta-1 cardiac effects such as palpitations or tachycardia can occur. Occasionally other adverse effects such as headache, insomnia, increased blood pressure, dizziness, nausea, and decreased PaO2 from worsened V/Q mismatch have been reported. The administration of high doses or continuous nebulization for relief of severe bronchospasm may result in hypokalemia and increased blood glucose and insulin levels.
- pirbuterol (Maxair): Pirbuterol is a beta-2 selective adrenergic bronchodilator. The drug is similar to albuterol in its saligenin structure and activity. The drug is available as a metered dose inhaler that is breath-actuated. The usual dosage is two puffs q4 to q6. The onset of activity is 5 to 8 minutes with a peak at 30 minutes and duration of approximately 5 hours. Pirbuterol can cause adverse effects such as tremor that are similar to those of other beta-2 agonists. Insomnia, irritability, and nausea have been reported by some patients. At higher dosage beta-2 selectivity is lost resulting in beta-1 effects such as palpitations and tachycardia.
- salmeterol (Serevent): Salmeterol is a beta-2 selective adrenergic agonist that is used for long-term maintenance therapy of asthma. It is suitable for asthmatic conditions that require daily use of a beta-2 agent along with inhaled corticosteroids, cromolyn or other prophylactic medications. The structure of the drug is a modification of the saligenin structure of albuterol resulting in somewhat different pharmacodynamics and pharmacologic effects from the other beta-2 selective agonists. Compared to those agents, salmeterol has a slower onset time, time to peak effect, and longer duration. It has also been shown to exert some anti-inflammatory effects, inhibiting histamine, leukotriene C4, D4, and prostaglandin D2 release as well as inhibiting the migration of inflammatory cells into the lung. The drug also exerts an effect by decreasing the vascular permeability that occurs during the inflammatory process. Patients with asthma must be instructed to use a shorter-acting beta-2 drug for treatment of breakthrough symptoms. Salmeterol should not be used for acute symptoms but should be continued on the regular dosing schedule. Two puffs of salmeterol should be administered by metered dose inhaler on a bid schedule. Occasionally tremor, headache, palpitations, or tachycardia may occur as adverse effects.
- ipratropium bromide (Atrovent): Ipratropium is a quaternary ammonium derivative of atropine. It is classified as an anticholinergic (parasympatholytic) bronchodilator. When delivered to the airways, the drug antagonizes the action of acetylcholine and blocks vagally- mediated bronchoconstriction. Although not initially thought to be useful for asthmatics, for some patients the anticholinergic agents appear to have flow rate improvements similar to the beta-2 agonists. Ipratropium is available as a metered dose inhaler with a dosage regimen of 2 puffs qid or as a solution for nebulization. The nebulizer dose is 5 mg every 6 to 8 hours. The most common adverse actions of ipratropium are cough and dry mouth although nervousness, headache, and nausea are reported by some patients. Patients should be cautioned not to point the inhaler toward their eyes to prevent changes of intraocular pressure, pupil size, or visual accommodation. During nebulizer delivery the eyes should be protected by using a reservoir tube attached to the tee to divert the aerosol away from the face. If the drug is delivered using a facemask, the patient's eyes should be closed or covered. The pharmacologic properties of ipratropium differ from those of the shorter-acting beta-2 inhaled drugs in having a longer time of onset, peak, and duration of action. Theoretically, the two classes of drugs should have complementary actions in managing the symptoms of asthma. Some respiratory practitioners believe that ipratropium should be given prior to a beta-agonist such as albuterol because anticholinergics exert their effect on the larger, more central airways. Other practitioners think that the beta-2 agonist should be administered first because of the quicker onset of action. Recently a metered dose inhaler containing both albuterol and ipratropium has been released (Combivent). Combining the two agents in a single inhaler has the advantage of patient convenience.