Disclosed is a method of treating in a subject of treating diseases and conditions that are beneficially treated by administering a CFTR potentiator The method comprises administering to the subject an amount in the range of about 50 mg to about 200 mg once a day of Compound (I) or (II) or pharmaceutically acceptable salts thereof, This invention also provides compositions comprising Compound (I) or (II) and the use of such compositions in methods.
