Pseudoephedrine is used to temporarily relieve sinus pressure and treat nasal congestion resulting from allergies, hay fever and the common cold, states MedlinePlus. However, the medication only treats symptoms and does not treat the underlying condition.
The nasal decongestant is sometimes used to prevent ear pain and blockage during changes in pressure, such as during flying or underwater diving, notes Medline Plus. This is not listed as an approved use of the drug on its labeling, but doctors may occasionally recommend it for this use with specific dosage instructions, says WebMD. Although the medication provides temporary relief from a stuffy nose caused by infections such as the flu, it can also treat symptoms caused by breathing illnesses such as bronchitis, reducing both congestion and inflammation.
Users should take pseudoephedrine tablets or liquid once every four to six hours as needed, and they may take extended-release tablets every 12 hours or according to manufacturer or physician's instructions, notes Medline Plus. If the user's symptoms do not improve within seven days or are present with a fever, the individual should stop taking the drug and contact a health care professional. Side effects of pseudoephedrine may include headache, nausea, vomiting, restlessness and weakness.