According to the Centers for Disease Control, more than 30.6 million Americans suffer from sinusitis. Sinus problems range from chronic conditions, such as allergic rhinitis, nasal polyps, deviated septum and chronic sinusitis, to seasonal sinus problems, such as allergies and the common cold. In every situation, the sinus cavity becomes swollen and produces an excessive amount of mucus, leading to nasal congestion, discharge and sinus pressure pain. Over-the-counter, or OTC, medications are used to treat the symptoms and assist the body in expelling mucus build-up. Check with your doctor before using an OTC medication.

The University of Iowa states that decongestants are used to relieve nasal congestion due to inflamed sinuses. Decongestants work by constricting the blood vessels in the nasal membranes. The decrease in blood flow to the sinuses causes them to shrink back to their normal size, allowing the person to breathe normally. It also allows any trapped fluid in the sinus cavity to drain more productively. Two OTC decongestants are available: pseudoephedrine and phenylephrine, according to the University of Iowa. Pseudoephedrine must be requested by the consumer via the pharmacist due to government regulation.

Antihistamines serve a dual purpose: They dry up excess fluid throughout the head and treat allergy symptoms, according to familydoctor.org. Antihistamines are separated by their function. Antihistamines that suppress the central nervous system and pass into the brain are considered first-generation antihistamines. They are known to make people drowsy, parched and are considered more powerful than second-generation. Second-generation antihistamines do not suppress the central nervous system and do not cause drowsiness or some of the other side effects of first-generation antihistamines. Antihistamines' primary function is to limit the amount of histamine the body produces, which alleviates common allergy symptoms, including sinus problems.

According to Medline Plus, pain relievers are used to reduce pain in the body. There are two types of pain relievers: acetaminophen and nonsteroidal anti-inflammatory drugs, or NSAIDs. NSAIDs such as aspirin and ibuprofen are recommended to treat sinus problems because they not only reduce the pain of sinus pressure but they also have an anti-inflammatory action. People with a bleeding disorder, stomach bleeding or who are pregnant or breastfeeding should not use NSAIDs, according to drugs.com. Pain relievers are commonly sold OTC in combination with decongestants and antihistamines. If you use any OTC medication, read each label carefully and follow the directions. You should consult your doctor before taking any medication.