An active ingredient is the ingredient that causes a medication to work. In the case of cough suppressants, each can have a different active ingredient. Cough suppressant medicines also include other inactive ingredients called excipients that aid in the manufacturing process and absorption of the active ingredient in the body.
Dextromethorphan
Dextromethorphan is found in over-the-counter medicines. It is a cough suppressant active ingredient that works by sending signals to the part of the brain to limit the cough reflex, according to Drugs.com. Dextromethorphan provides relief from a cough stemming from a cold or flu, according to MedlinePlus. It comes as a lozenge, dissolving strip, liquid syrup, liquid-filled capsule or a chewable tablet. Dextromethorphan is sometimes combined with other active ingredients that also work to suppress coughs such as decongestants and antihistamines.
Benzonatate
Benzonatate is a cough suppressant active ingredient that is available only by prescription, according to MedlinePlus. It works by suppressing the cough reflex in the body’s air passages and lungs. It comes as a liquid-filled or regular capsule. Benzonatate treats a cough stemming from the common cold, pneumonia, bronchitis and other lung infections.
Codeine and Promethazine
Codeine is a cough suppressant active ingredient. Codeine suppresses a cough by limiting brain activity that causes coughing. According to MedlinePlus, however, when used as a cough suppressant, codeine is paired with another active ingredient such as promethazine, an antihistamine. The combination of promethazine and codeine treats symptoms of a cough stemming from the common cold or allergies. The combination comes as a liquid syrup and is available by prescription.
