Cystic fibrosis (CF) is the most common inherited fatal disorder among Caucasians. Bronchial mucus in CF contains more
potassium and less
sodium, which may be due to increased
sodium absorption, resulting in a reduced airway water content. We studied 23 patients with CF after inhalation of
normal saline or
amiloride (10(-3) M), a
sodium transport blocker. Mucociliary clearance (MC) and
cough clearance (CC) were determined with a
gamma camera that traced the movement of 99mTc-labeled, hardened erythrocytes over a 1-h period after the patients inhaled these particles as an
aerosol. Before and after each investigation pulmonary function tests (PFT) and blood pressure (BP) were measured. Sputum thread formation was measured by means of a filancemeter. Six of the patients also completed a 3-wk trial of
amiloride inhalation therapy. MC increased significantly (p less than 0.001) after acute
amiloride inhalation (bronchial deposition, 0.07 mg
amiloride) compared with that in the saline control. CC also increased, but not as much as MC. After 3 wk of
amiloride inhalation (2 times a day) clearance values (both MC and CC) were markedly enhanced (p less than 0.01); after a similar period of saline inhalation, clearance values were not different from baseline. Sputum filance values also decreased significantly after
amiloride inhalation. There were no adverse effects of the
amiloride inhalation compared with saline. We conclude that
amiloride inhalation administered as a single dose or as long-term
therapy is able to increase MC and CC in CF airways and that the effect of 10(-3) M
amiloride inhalation on MC lasts at least 40 min. (ABSTRACT TRUNCATED AT 250 WORDS)