Both of these promote the movement of water into the secretions.
Expectorants also liquify thick mucous by increasing the amount of fresh respiratory secretions.
The reasoning is that softer secretions are easier to cough out. Agitation and insomnia occur more frequently with oral than topical forms. Instruct the hypertensive Client not to take decongestants without consulting a physician or pharmacist about blood pressure effects. These medications suppress the urge to cough. To increase effectiveness of cough suppression while decreasing uncomfortable side effects, combinations of various types of antitussives have been made.