Clioquinol is a broad-spectrum antibacterial with antifungal properties, bacteriostatic. It is used as an antifungal and antiprotozoal topical drug OTC product for treatment of human infections. Previousely was used for wide number of intestinal disorders including lambliasis, shigellosis, balantidiral dysentery and some forms of diarrheas. The physiologic effect of clioquinol is by increased histamine release and cell-mediated immunity. It is a member of a family hydroxyquinolines which inhibit certain enzymes related to DNA replication. It is a copper, iron and zink chelating agent. It is an organic molecule with a quinolinic acid as its apparent core which itself is a neurotransmitter. In large doses it possesses neurotoxicity and may induce neurological disease such as subacute myelo-optic neuropathy by creating copper deficiency that leads to zink excess. SMON (Sub-Acute-Myelo-Optical-Neuropathy) - a polio-like disease began as an epidemic in 1959 in Japan was believed to be a Clioquinol caused. Clioquinol is a standardized chemical allergen. It has been resurrected as a potential treatment for Alzheimer's disease since it perturbs metallo-chemistry of amyloid and clioquinol treatment has been shown to be beneficial in a mouse model of Alzheimer's disease.

Chlophedianol (Clofedanol) is a centrally-acting cough suppressant, although the mechanism of action is not known. It is available in Canada under the trade name Ulone. It is not available in the United States. Chlophedianol (Clofedanol) suppresses the cough reflex by a direct effect on the cough center in the medulla of the brain. It also has local anesthetic and antihistamine properties, and may have anticholinergic effects at high doses.

Xylometazoline, also spelled xylomethazoline, is a medication which is used to improve symptoms of nasal congestion, allergic rhinitis, and sinusitis. Xylometazoline was patented in 1956 and came into medical use in 1959. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The drug works by stimulating adrenergic receptors on the lamina propria of blood vessels in the nose. The decongestant effect is due to constriction of large veins in the nose which swell up during the inflammation of any infection or allergy of the nose. The smaller arteries are also constricted and this causes the colour of the nasal epithelium to be visibly paler after dosage. The standard adult solution strength is 0.1% w/v xylometazoline (or 1 mg per 1 mL solution), and the dose for children under 12 is usually 0.05% (0.5 mg/mL).

DEXBROMPHENIRAMINE is an alkylamine derivative with anticholinergic and sedative properties. It is a histamine H1-receptor antagonist that competes with histamine for the H1-receptor sites on effector cells in the gastrointestinal tract, blood vessels, and respiratory tract. The antagonistic action of this agent blocks the activities of endogenous histamine, which subsequently leads to temporary relief from the negative histamine-mediated symptoms of an allergic reaction such as bronchoconstriction, vasodilation, increased capillary permeability and spasmodic contractions of the gastrointestinal smooth muscle. DEXBROMPHENIRAMINE as a part of combination medicine is used to treat symptoms of the common cold or seasonal allergies, including sneezing, runny or stuffy nose, and itchy, watery eyes.

Triprolidine is a first generation histamine H1 antagonist, which in combination with codeine phosphate and pseudoephedrine hydrochloride is sold under brand name TRIACIN-C. TRIACIN-C is indicated for temporary relief of coughs and upper respiratory symptoms, including nasal congestion, associated with allergy or the common cold.

Dexchlorpheniramine, the d-isomer of the racemic compound chlorpheniramine, is two times more active than chlorpheniramine. Dexchlorpheniramine does not prevent the release of histamine, but rather, competes with free histamine for binding at the H1-receptor sites, and competitively antagonizes the effects of histamine on H1-receptors in the GI tract, uterus, large blood vessels, and bronchial muscle. Blockade of H1-receptors also suppresses the formation of oedema, flare, and pruritus that result from histaminic activity. Since dexchlorpheniramine binds to central and peripheral H1-receptors, sedative effects are likely to occur. H1-antagonists are structurally similar to anticholinergic agents and therefore possess the potential to exhibit anticholinergic properties of varying degrees. They also have antipruritic effects. Dexchlorpheniramine has high antihistaminic activity, moderate anticholinergic effects and minimal sedative effects. The drug does not possess antiemetic properties.

Brompheniramine is an antihistaminergic medication of the propylamine class. It is a first-generation antihistamine, which is used for the treatment of the symptoms of the common cold and allergic rhinitis, such as runny nose, itchy eyes, watery eyes, and sneezing. In allergic reactions, an allergen interacts with and cross-links surface IgE antibodies on mast cells and basophils. Once the mast cell-antibody-antigen complex is formed, a complex series of events occurs that eventually leads to cell-degranulation and the release of histamine (and other chemical mediators) from the mast cell or basophil. Once released, histamine can react with local or widespread tissues through histamine receptors. Brompheniramine is a histamine H1 antagonist of the alkylamine class. It provides effective, temporary relief of sneezing, watery and itchy eyes, and runny nose due to hay fever and other upper respiratory allergies. Brompheniramine is metabolised by cytochrome P450s. The halogenated alkylamine antihistamines all exhibit optic isomerism and brompheniramine products contain racemic brompheniramine maleate whereas dexbrompheniramine (Drixoral) is the dextrorotary (right-handed) stereoisomer.

Dyclonine is an local anesthetic used to provide topical anesthesia to mucous membranes through sodium channel inhibition. It is the active ingredient in Sucrets, an over-the-counter throat lozenge. It has been used as a local anesthetic agent prior to laryngoscopy, bronchoscopy, esophagoscopy, or endotracheal intubation. However, oral solutions no longer are commercially available in the US. Recently, additional activities of dyclonine have been discovered. Dyclonine represents a novel therapeutic strategy that can potentially be repurposed for the treatment of Friedreich's ataxia. Dyclonine enhances the cytotoxic effect of proteasome inhibitors on cancer and multiple myeloma cells.

Tetrahydrozoline is an alpha adrenergic receptor agonist, which is used in form of nasal solution or spray (Tyzin) for decongestion of nasal and nasopharyngeal mucosa.

Dextromethorphan is a non-narcotic morphine derivative widely used as an antitussive for almost 40 years. It has attracted attention due to its anticonvulsant and neuroprotective properties. It is a cough suppressant in many over-the-counter cold and cough medicines. In 2010, the FDA approved the combination product dextromethorphan/quinidine for the treatment of pseudobulbar affect. Dextromethorphan suppresses the cough reflex by a direct action on the cough center in the medulla of the brain. Dextromethorphan shows high-affinity binding to several regions of the brain, including the medullary cough center. This compound is an NMDA receptor antagonist and acts as a non-competitive channel blocker. It is one of the widely used antitussives and is used to study the involvement of glutamate receptors in neurotoxicity. Dextromethorphan (DM) is a sigma-1 receptor agonist and an uncompetitive NMDA receptor antagonist. The mechanism by which dextromethorphan exerts therapeutic effects in patients with pseudobulbar affect is unknown. Dextromethorphan should not be taken with monoamine oxidase inhibitors due to the potential for serotonin syndrome. Dextromethorphan is extensively metabolized by CYP2D6 to dextrorphan, which is rapidly glucuronidated and unable to cross the blood-brain barrier.