Unsure about the hundreds of cold and flu preparations on the drugstore shelves? You're not alone. Deciding among the OTC (over-the-counter) remedies for cold, flu, or allergy symptoms can be intimidating, and a basic understanding of the types of drugs contained in these medications can help you make an informed choice.
Decongestants are the drugs of choice for a stuffy, congested nose. Decongestants act by narrowing the blood vessels in the nose, leading to decreased blood flow in the nasal tissues and reduced leakage of fluid from the nose. Decongestants can either be taken orally or applied locally (topically) in the form of nasal sprays or drops.
Pseudoephedrine (for example, loratadine and pseudoephedrine [Claritin-D], Sudafed, fexofenadine and pseudoephedrine [Allegra D]) and phenylephrine are decongestants that can be taken orally. Phenylephrine and oxymetolazone are examples of topical decongestants. While topical decongestants are effective after a few minutes, oral preparations (tablets) can take about 30 minutes to work. Decongestants act as stimulants that can increase heart rate, raise the blood pressure, exacerbate palpitations, and lead to feelings of nervousness or feeling "hyper."
It's important to note that decongestants do not relieve a runny or itchy nose.
Antihistamines counteract the effects of histamine, a chemical released by the body during allergic reactions. Histamines can cause sneezing, itching of the throat and eyes, and a runny nose. Over-the-counter antihistamines belong to one of two groups: first-generation antihistamines and the newer second-generation antihistamines.
The drugs found in first-generation OTC antihistamines include:
- chlorpheniramine (for example, Tannate-12 S, Tannihist-12 RF, Trionate, Tussi-12 S, Tussizone-12 RF, Tussionex)
- doxylamine, and
- diphenhydramine (Benadryl).
They generally have an opposite effect from decongestants and can be sedating. Paradoxically, infants and children may sometimes become irritable after taking antihistamines. Common OTC antihistamines take about 30-60 minutes to work. Loratidine (Claritin, Claritin RediTabs, Alavert, and others) is an example of the newer, second-generation antihistamines that is available OTC.
The second-generation antihistamines do not possess the sedating effects of the older, first-generation antihistamines.
Expectorants are medicines that help bring up mucus from the airways. Guaifenesin (Humibid, Humibid LA, Robitussin, Organidin NR, Fenesin) is a common expectorant. It promotes drainage of mucus from the lungs by thinning the mucus and also by lubricating the irritated respiratory tract.
Cough suppressants are intended to decrease coughing. A common OTC cough suppressant is dextromethorphan (Robitussin, Vicks 44), which acts on the brain to suppress coughing. Interestingly, dextromethorphan was not found to be any more effective than placebo in clinical trials involving children, and there are no indications established for its use in children. Suppression of coughing can also be dangerous in people suffering from certain airway diseases. Coughs due to upper airway viral infections can be treated simply with humidity and fluid administration.
Combination preparations containing one or more of the above drugs, sometimes along with pain and fever reducing drugs (aspirin, acetaminophen, ibuprofen, or naproxen sodium) are common. These are available in both tablet and liquid form. The liquid preparations are particularly useful for children who may need smaller doses. Combination decongestant/antihistamine medications can be well-tolerated since the stimulant effect of the decongestant and the sedative effect of the antihistamine often offset each other.
Remember to read the labels and note which active ingredients are contained in any medications you are taking. You should not take additional pain or fever reducing drugs if you are taking a combination medication that includes them. Your pharmacist or doctor can guide you to appropriate preparations for your particular symptoms and condition.
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UpToDate.com. Patient information: Chronic cough in adults (Beyond the Basics).