Mesoridazine besylate is a phenothiazine dopamine receptor anatagonist. Mesoridazine besylate is described to demonstrate inhibition for D2DR and D4DR. It has a high affinity for dopamine D4 receptor. Mesoridazine besylate is an antipsychotic agent.

Mepyramine maleate, also known as Pyrilamine maleate, is a histamine H1 antagonist. 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.

Mepivacaine Hydrochloride is a local anesthetic. It reversibly blocks inward current of transient Na+, as well as the steady-state K+ outward current. Mepivacaine Hydrochloride blocks tandem pore (TASK) and Kv1.5, potassium channels in model systems.

Mepenzolate Bromide is a muscarinic antagonist used to treat gastrointestinal disorders. It decreases the severity of elastase-induced airspace enlargement and respiratory dysfunction.

Memantine Hydrochloride is the hydrochloride salt of memantine, a low-affinity, voltage-dependent, noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist. Memantine binds to and inhibits cation channels of glutamanergic NMDA receptors located in the central nervous system, preventing the prolonged influx of calcium ions and the associated neuronal excitotoxicity, and thereby potentially enhancing cognitive function. Memantine is also a 5-hydroxytryptamine type 3 (5HT3) receptor and nicotinic receptor antagonist.

Mefenamic Acid is a non-steroidal anti-inflammatory agent with analgesic, anti-inflammatory, and antipyretic properties. It is an inhibitor of cyclooxygenase and has demonstrated antiproliferative activity against colorectal cancer cells.

Meclofenamic acid is a drug used for joint, muscular pain, arthritis and dysmenorrhea. Meclofenamic acid is a non-steroidal anti-inflammatory agent with antipyretic and antigranulation activities. It also inhibits prostaglandin biosynthesis. It is a member of the anthranilic acid derivatives class of NSAID drugs and was approved by the FDA in 1980. Like other members of the class, it is a COX inhibitor and prevents formation of prostaglandins.

Meclizine dihydrochloride is a histamine H1 antagonist used in the treatment of motion sickness, vertigo, and nausea during pregnancy and radiation sickness. Meclizine hydrochloride increases human pregnane X receptor (hPXR) target gene expression in human hepatocyte primary cultures.

Maprotiline Hydrochloride is the hydrochloride salt form of maprotiline, a tetracyclic antidepressant closely related to the tricyclic antidepressants with adrenergic activity and sedative properties. Maprotiline hydrochloride exerts its effect by blocking the re-uptake of norepinephrine, thereby increasing the synaptic concentration of norepinephrine in the central nervous system and subsequently prolonging the action of norepinephrine on central receptors.

Malathion is an organophosphorous compound that inhibits cholinesterase enzyme activity. Malathion contains an interesting phosphinothioyl-thio ester as its active moiety where modification of acetylcholinesterase occurs. The action of Malathion on acetylcholinesterase has been correlated to prolonged modulation of the functioning of the cutaneous vasculature. Malathion is an organophosphate insecticide of relatively low human toxicity.

Lumefantrine, also known as HSDB 7210, is an antimalarial agent used to treat acute uncomplicated malaria. It is administered in combination with artemether for improved efficacy. This combination therapy exerts its effects against the erythrocytic stages of Plasmodium spp. and may be used to treat infections caused by P. falciparum and unidentified Plasmodium species, including infections acquired in chloroquine-resistant areas.

Lofexidine Hydrochloride is an alpha2-adrenergic receptor agonist that is structurally related to Clonidine and used in the treatment of opioid withdrawal symptoms as well as an anihypertensive. It can be used as a short acting anti-hypertensive.

Lisuride maleate is an ergot derivative that acts as an agonist at dopamine D2 receptors, a dopamine agonist. It may also act as an antagonist at dopamine D1 receptors, and as an agonist at some serotonin receptors. It displays high affinity for D2, D3 and D4 receptors along with 5-HT1A. Lisuride maleate is also known as an anti-Parkinson's agent.

Lindane is an organochlorine chemical variant of hexachlorocyclohexane that has been used both as an agricultural insecticide and as a pharmaceutical treatment for lice and scabies. Lindane is a neurotoxin that interferes with GABA neurotransmitter function by interacting with the GABAA receptor-chloride channel complex at the picrotoxin binding site. In humans, lindane affects the nervous system, liver and kidneys, and may well be a carcinogen. It is unclear whether lindane is an endocrine disruptor.

Levobunolol is a non-selective beta blocker. It is used topically to manage glaucoma.

Labetalol is a mixed alpha/beta adrenergic antagonist that is used to treat high blood pressure. It can be given intravenously in severe hypertensive situations, or by mouth for long term hypertension management. Studies suggest that the pharmacokinetics of labetalol are significantly affected by the common CYP2C19 polymorphisms.

Ketorolac or ketorolac tromethamine is a non-steroidal anti-inflammatory drug (NSAID) in the family of heterocyclic acetic acid derivatives, used as an analgesic. It acts by inhibiting the bodily synthesis of prostaglandins. Ketorolac in its oral (tablet or capsule) and intramuscular (injected) preparations is a racemic mixture of both (S)-(?)-ketorolac, the active isomer, and (R)-(+)-ketorolac. An ophthalmic solution of ketorolac is also used to treat eye pain and to relieve the itchiness and burning of seasonal allergies.

Ketoconazole is a synthetic imidazole antifungal drug used primarily to treat fungal infections. It is sold commercially as a tablet for oral administration (although this use has been discontinued in a number of countries), and in a variety of formulations for topical administration, such as creams (used to treat tinea; cutaneous candidiasis, including candidal paronychia; and pityriasis versicolor) and shampoos (used primarily to treat dandruff—seborrhoeic dermatitis of the scalp).

Isopropamide (R5) is a long-acting anticholinergic drug. It is used in the treatment of peptic ulcers and other gastrointestinal disorders involving hyperacidity (gastrointestinal acidosis) and hypermotility. Chemically, it contains a quaternary ammonium group. It is most often provided as an iodide salt, but is also available as a bromide or chloride salt.

Iohexol is a contrast agent. The osmolality of iohexol ranges from 322 mOsm/kg—approximately 1.1 times that of blood plasma—to 844 mOsm/kg, almost three times that of blood. Despite this difference, iohexol is still considered a low-osmolality contrast agent. The osmolality of older agents, such as diatrizoate, may be more than twice as high.

Iodixanol is a contrast agent. It is commonly used as a contrast agent during coronary angiography. It is the only iso-osmolar contrast agent, with an osmolality of 290 mOsm/kg H2O—the same as blood.

Imipramine, sold as Tofranil and also known as melipramine, is a tricyclic antidepressant (TCA) of the dibenzazepine group. Imipramine is mainly used in the treatment of major depression and enuresis (inability to control urination).

Imipenem is an intravenous β-lactam antibiotic discovered by Merck scientists Burton Christensen, William Leanza, and Kenneth Wildonger in 1980. It was the first member of the carbapenem class of antibiotics. Carbapenems are highly resistant to the β-lactamase enzymes produced by many multiple drug-resistant Gram-negative bacteria, and thus play a key role in the treatment of infections not readily treated with other antibiotics.

Iloprost is a drug used to treat pulmonary arterial hypertension (PAH), scleroderma, Raynaud's phenomenon and other diseases in which the blood vessels are constricted and blood can't flow to the tissues. This damages the tissues and causes high blood pressure. Iloprost works by opening (dilating) the blood vessels to allow the blood to flow through again. Note: This product is supplied as acetone solution (10 mg /mL)

Icosapent is a synthetic derivative of the omega-3 fatty acid eicosapentaenoic acid (EPA). A diet rich in eicosapentaenoic acid lowers serum lipid concentration, reduces incidence of cardiovascular disorders, prevents platelet aggregation, and inhibits arachidonic acid conversion into the thromboxane-2 and prostaglandin-2 families.

Hydroxyzine dihydrochloride is a histamine H1 receptor antagonist that is effective in the treatment of chronic urticaria, dermatitis, and histamine-mediated pruritus. Unlike its major metabolite cetirizine, it does cause drowsiness. It is also effective as an antiemetic, for relief of anxiety and tension, and as a sedative.

Hydroflumethiazide is a thiazide diuretic with actions. It is also an anti-hypertensive and a diuretic.The physiologic effect of hydroflumethiazide is by means of increased diuresis.

Homatropine Methylbromide is a quaternary ammonium salt of methylhomatropine. It is a peripherally acting anticholinergic medication that inhibits muscarinic acetylcholine receptors and thus the parasympathetic nervous system. It does not cross the blood–brain barrier. It is used to effectively relieve intestinal spasms and abdominal cramps, without producing the adverse effects of less specific anticholinergics. It is used, in addition to papaverine, as component of mild drugs that help "flush" the bile.

Hexafluronium bromide is a neuromuscular blocking agent used in anesthesiology to prolong and potentiate the skeletal muscle relaxing action of suxamethonium during surgery. It is known to bind and block the activity of plasma cholinesterases. Hexafluronium acts as a nicotinic acetylcholine receptor antagonist.

Hetacillin is a beta-lactam antibiotic that is part of the aminopenicillin family. Hetacillin is a prodrug that is converted to ampicillin via esterases. Ampicillin binds to inactivated penicillin-binding proteins (PBPs) located on the inner membrane of the bacterial cell wall. PBPs, including transpeptidases, carboxypeptidases, and endopeptidases, participate in the terminal stages of assembling the bacterial cell wall and in reshaping the cell wall during growth and division. It is a prodrug and it has no antibacterial activity itself but quickly splits of acetone in the human body to form ampicillin, which is active against a variety of bacteria.