Chlorpheniramine is an antihistamine. Chlorpheniramine binds to the histamine H1 receptor. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine. Chlorpheniramine is used for relieving symptoms of sinus congestion, sinus pressure, runny nose, watery eyes, itching of the nose and throat, and sneezing due to upper respiratory infections (eg, colds), allergies, and hay fever. In addition to being a histamine H1 receptor (HRH1) antagonist, chlorphenamine has been shown to work as a serotonin-norepinephrine reuptake inhibitor or SNRI.

Chlorcyclizine is a first generation phenylpiperazine class antihistamine used to treat urticaria, rhinitis, pruritus, and other allergy symptoms. Chlorcyclizine also has some local anesthetic, anticholinergic, and antiserotonergic properties, and can be used as an antiemetic. Chlorcyclizine temporarily relieves the symptoms due to hay fever or other upper respiratory allergies. It has also being shown to possess in vitro and in vivo activity against hepatitis C virus.

Thonzylamine (also known as neohetramine) is an antihistamine and anticholinergic drug, which is used in combination with others compounds for the temporarily relieves symptoms due to the common cold: hay fever (allergic rhinitis) or other upper respiratory allergies: nasal congestion; runny nose and so on. In addition, thonzylamine was investigated for the treatment of tuberculosis, when this drug caused a slight reduction in the extent of tuberculosis in experimentally infected guinea pigs and caused a slight but significant increase in the length of survival.

Pheniramine is an antihistamine used to treat allergic conditions such as hay fever or urticaria. It is generally sold in combination with other medications, rather than as a stand-alone drug. Allergies are caused by an excessive type 1 hypersensitivity response of the body to allergens, mediated by inappropriate histamine signalling. By inhibiting the binding of histamine, antihistamines decrease the normal histamine response from cells, consequently decreasing allergic symptoms. Antihistamines such as pheniramine appear to compete with histamine for histamine H1- receptor sites on effector cells. The antihistamines antagonize those pharmacological effects of histamine which are mediated through activation of H1- receptor sites and thereby reduce the intensity of allergic reactions and tissue injury response involving histamine release. Antihistamines suppress the histamine-induced wheal (swelling) and flare (vasodilation) response by blocking the binding of histamine to its receptors on nerves, vascular smooth muscle, glandular cells, endothelium, and mast cells. They effectively exert competitive antagonism of histamine for H1-receptors. Pheniramine is marketed under the trade name Avil and Visine-A among others).

Pyrilamine (also known as Mepyramine) is a first generation antihistamine, targeting the H1 receptor. However, it rapidly permeates the brain and so often causes drowsiness as a side effect. It is used in over-the-counter combination products for colds and menstrual symptoms. Mepyramine is a histamine H1 receptor inverse agonist. It binds to a G protein-coupled form of the receptor and promotes a G protein-coupled inactive state of the H1 receptor that interferes with the Gq/11-mediated signaling. Mepyramine competes with histamine for binding at H1-receptor sites on the effector cell surface, resulting in suppression of histaminic edema, flare, and pruritus. The sedative properties of Mepyramine occur at the subcortical level of the CNS. It has mild hypnotic properties and some local anesthetic action and is used for allergies (including skin eruptions) both parenterally and locally. It is a common ingredient of cold remedies.

Doxylamine is an antihistamine commonly used as a sleep aid. This drug is also used to relieve symptoms of hay fever (allergic rhinitis), hives (rash or itching), and other allergic reactions. Doxylamine is a member of the ethanolamine class of antihistamines and has anti-allergy power far superior to virtually every other antihistamine on the market, with the exception of diphenhydramine (Benadryl). It is also the most powerful over-the-counter sedative available in the United States, and more sedating than many prescription hypnotics. In a study, it was found to be superior to even the barbiturate, phenobarbital for use as a sedative. Doxylamine is also a potent anticholinergic. Like other antihistamines, doxylamine acts by competitively inhibiting histamine at H1 receptors. It also has substantial sedative and anticholinergic effects. Used alone as a short-term sleep aid, in combination with other drugs as a night-time cold and allergy relief drug. Also used in combination with Vitamin B6 (pyridoxine) to prevent morning sickness in pregnant women.

Phenindamine (thephorin or 2-methyl-9-phenyl-2,3,4,9-tetrahydro-1-pyridindene) a pyridindene derivative proved to be a potent antihistaminic. Phenindamine was used to treat sneezing; runny nose; itching, watery eyes; hives; rashes; itching; and other symptoms of allergies and the common cold.

Diphenhydramine is an antihistamine which is used in the combination with naproxen sodium for the relief of occasional sleeplessness when associated with minor aches and pains. Diphenhydramine has a role nighttime sleep-aid and naproxen sodium is a pain reliever. In addition, diphenhydramine used in relieving symptoms in patients with moderate-to-severe seasonal allergic rhinitis. Diphenhydramine acts as an antagonist of histamine H1 receptor. Besides, was shown potential to repurpose diphenhydramine as an anti-melanoma therapeutic agent, it induces melanoma cell apoptosis by suppressing STAT3/MCL-1 survival signaling pathway.

Algeldrate (Aluminium hydroxide) is the amphoteric inorganic compound used as an antacid in the treatment of Duodenal, Peptic and Stomach Ulcer and some other conditions. Aluminium hydroxide is preferred over other alternatives such as sodium bicarbonate because Al(OH)3, being insoluble, does not increase the pH of stomach above 7 and hence, does not trigger secretion of excess acid by the stomach. Brand names include Alu-Cap, Aludrox, Gaviscon or Pepsamar. It reacts with the excess acid in the stomach, reducing the acidity of the stomach content, which may relieve the symptoms of ulcers, heartburn or dyspepsia. Such products can cause constipation, because the aluminum ions inhibit the contractions of smooth muscle cells in the gastrointestinal tract, slowing peristalsis and lengthening the time needed for stool to pass through the colon. Some such products (such as Maalox) are formulated to minimize such effects through the inclusion of equal concentrations of magnesium hydroxide or magnesium carbonate, which have counterbalancing laxative effects. This compound is also used to control phosphate (phosphorus) levels in the blood of people suffering from kidney failure. Precipitated aluminum hydroxide is included as an adjuvant in some vaccines (e.g. anthrax vaccine). One of the well-known brands of aluminum hydroxide adjuvant is Alhydrogel, made by Brenntag Biosector. Since it absorbs protein well, it also functions to stabilize vaccines by preventing the proteins in the vaccine from precipitating or sticking to the walls of the container during storage. Aluminium hydroxide is sometimes mistakenly called "alum", which properly refers to aluminum potassium sulfate. Vaccine formulations containing aluminum hydroxide stimulate the immune system by inducing the release of uric acid, an immunological danger signal. This strongly attracts certain types of monocytes which differentiate into dendritic cells. The dendritic cells pick up the antigen, carry it to lymph nodes, and stimulate T cells and B cells. It appears to contribute to induction of a good Th2 response, so is useful for immunizing against pathogens that are blocked by antibodies. In the 1960s and 1970s, it was speculated that aluminum was related to various neurological disorders including Alzheimer's disease. Since then, multiple epidemiological studies have found no connection between exposure to aluminum and neurological disorders.

Bamirastine (previously known as TAK 427), an antiallergic compound that inhibits ligand binding to recombinant human histamine H1 receptor. The drug was involved in phase II clinical trials for the treatment of allergic rhinitis and for patients with atopic dermatitis. However, these studies were discontinued.