Over-the-counter (OTC) drugs are medicines sold directly to a consumer without a requirement for a prescription from a healthcare professional, as opposed to prescription drugs, which may be supplied only to consumers possessing a valid prescription. In many countries, OTC drugs are selected by a regulatory agency to ensure that they contain ingredients that are safe and effective when used without a physician's care. OTC drugs are usually regulated according to their active pharmaceutical ingredient (API) rather than final products. By regulating APIs instead of specific drug formulations, governments allow manufacturers the freedom to formulate ingredients, or combinations of ingredients, into proprietary mixtures.
Cold medicines are a group of medications taken individually or in combination as a treatment for the symptoms of the common cold and similar conditions of the upper respiratory tract. The term encompasses a broad array of drugs, including analgesics, antihistamines and decongestants, among many others. It also includes drugs which are marketed as cough suppressants or antitussives, but their effectiveness in reducing cough symptoms is unclear or minimal.
H1 antagonists, also called H1 blockers, are a class of medications that block the action of histamine at the H1 receptor, helping to relieve allergic reactions. Agents where the main therapeutic effect is mediated by negative modulation of histamine receptors are termed antihistamines; other agents may have antihistaminergic action but are not true antihistamines.
Loratadine, sold under the brand name Claritin among others, is a medication used to treat allergies. This includes allergic rhinitis and hives. It is also available in combination with pseudoephedrine, a decongestant, known as loratadine/pseudoephedrine. It is taken orally.
A decongestant, or nasal decongestant, is a type of pharmaceutical drug that is used to relieve nasal congestion in the upper respiratory tract. The active ingredient in most decongestants is either pseudoephedrine or phenylephrine. Intranasal corticosteroids can also be used as decongestants and antihistamines can be used to alleviate runny nose, nasal itch, and sneezing.
Benadryl is a brand of various antihistamine medications used to stop allergies, whose content varies in different countries, but which includes some combination of diphenhydramine, acrivastine, and/or cetirizine.
Dimenhydrinate, sold under the brand name Dramamine, among others, is an over-the-counter drug used to treat motion sickness and nausea. Dimenhydrinate is a theoclate salt composed of diphenhydramine, an ethanolamine derivative, and 8-chlorotheophylline, a chlorinated theophylline derivative, in a 1:1 ratio.
Chlorphenamine, also known as chlorpheniramine, is an antihistamine used to treat the symptoms of allergic conditions such as allergic rhinitis. It is taken by mouth. The medication takes effect within two hours and lasts for about 4-6.
Doxylamine, sold under the brand name Unisom among others, is an antihistamine medication which is used in the treatment of insomnia and allergies. In combination with pyridoxine (vitamin B6), it is also used to treat morning sickness in pregnant women. Doxylamine is available over-the-counter, and is used in nighttime cold medicines, such as NyQuil, as well as in pain medications containing acetaminophen and codeine, to help with sleep. The medication is taken by mouth.
Clemastine, also known as meclastin, is a first-generation H1 histamine antagonist (antihistamine) with anticholinergic properties (drying) and sedative side effects. Like all first-generation antihistamines, it is sedating.
Coricidin, Coricidin 'D' (decongestant), or Coricidin HBP, is the name of a drug marketed by Schering-Plough that contains dextromethorphan and chlorpheniramine maleate. It is now owned by Bayer. Varieties of Coricidin may also contain acetaminophen and guaifenesin.
Phenyltoloxamine is an antihistamine with sedative and analgesic effects. It is available in combination with other drugs such as paracetamol (acetominophen).
Levocetirizine, sold under the brand name Xyzal among others, is a second-generation antihistamine used for the treatment of allergic rhinitis and long term hives of unclear cause. It is less sedating than older antihistamines. It is taken by mouth.
Cyclizine, sold under a number of brand names, is a medication used to treat and prevent nausea, vomiting and dizziness due to motion sickness or vertigo. It may also be used for nausea after general anaesthesia or that which developed from opioid use. It is taken by mouth, in the rectum, or injected into a vein.
Pheniramine is an antihistamine with anticholinergic properties used to treat allergic conditions such as hay fever or urticaria. It has relatively strong sedative effects, and may sometimes be used off-label as an over-the-counter sleeping pill in a similar manner to other sedating antihistamines such as diphenhydramine. Pheniramine is also commonly found in eyedrops used for the treatment of allergic conjunctivitis.
Acrivastine is a medication used for the treatment of allergies and hay fever. It is a second-generation H1-receptor antagonist antihistamine and works by blocking histamine H1 receptors.
Mepyramine, also known as pyrilamine, is a first generation antihistamine, targeting the H1 receptor as an inverse agonist. Mepyramine rapidly permeates the brain, often causing drowsiness. It is often sold as a maleate salt, pyrilamine maleate.
Oxomemazine is an antihistamine and anticholinergic of the phenothiazine chemical class for the treatment of cough.
Guaifenesin/phenylephrine is a combination of the drugs guaifenesin and phenylephrine and is a preparation against the symptoms of cold, flu and allergy. Guaifenesine is an expectorant, phenylephrine is a decongestant. The drug is sold under the brand name Entex and as generic brands. Entex La is 400 mg guaifenesin and 30 mg phenylephrine hydrochloride. Entex Pse is 600 mg guaifenesin and 120 mg phenylephrine hydrochloride. Both are extended release products, meaning that the non-active ingredients are chosen to dissolve slowly to provide a prolonged therapeutic effect.
Meclizine, sold under the brand name Bonine, among others, is an antihistamine used to treat motion sickness and dizziness (vertigo). It is taken by mouth. Effects generally begin in an hour and last for up to a day.
