Dexmedetomide (biologically active dextroisomer of medetomidine) is an alpha2-adrenergic agonist which was approved by FDA for the sedation purposes. Upon administration the drug activates the alpha2 receptors thus inhibiting the release of norepinephrine and terminating the propagation of pain signals. Also it inhibits sympathetic activity and thus can decrease blood pressure and heart rate.

Levalbuterol is the (R)-enantiomer of the drug substance racemic albuterol (salbutamol). Binding studies have demonstrated that (R)-albuterol binds to the beta2-adrenergic receptor with a high affinity, whereas (S)-albuterol binds with 100-fold less affinity than (R)-albuterol. Other evaluations have suggested that (R)-albuterol possesses the bronchodilatory, bronchoprotective, and ciliary-stimulatory properties of racemic albuterol, while (S)-albuterol does not contribute beneficially to the therapeutic effects of the racemate and was originally assumed to be inert. Xopenex (levalbuterol HCl) Inhalation Solution is indicated for the treatment or prevention of bronchospasm in adults, adolescents, and children 6 years of age and older with reversible obstructive airway disease.

Rabeprazole was discovered by Eisai Co., Ltd. Janssen Pharmaceutica N.V. and Eisai Co., Ltd. have a strategic alliance in which Eisai and Janssen-Cilag co-promote the drug in Germany and the U.K. In the US rabeprazole sodium is co-promoted under the brand name AcipHex by Eisai Inc. and Janssen Pharmaceutica Inc. Pariet is available through Janssen-Cilag in most other countries excluding Japan and some Asian countries. Rabeprazole is an antiulcer drug in the class of proton pump inhibitors. Rabeprazole is a prodrug and is converted to the active sulphenamide form in the acid environment of the parietal cells. Rabeprazole is used to heal and maintain the healing of Erosive or Ulcerative Gastroesophageal Reflux Disease (GERD), for healing Duodenal Ulcers, and for treatment of pathological hypersecretory conditions such as Zollinger-Ellison Syndrome. Rabeprazole suppresses gastric acid secretion by inhibiting the gastric H , K ATPase at the secretory surface of the gastric parietal cell and does not exhibit anticholinergic or histamine H2-receptor antagonist properties. Because this enzyme is regarded as the acid (proton) pump within the parietal cell, rabeprazole has been characterized as a gastric proton-pump inhibitor which blocks the final step of gastric acid secretion. In gastric parietal cells, rabeprazole is protonated, accumulates, and is transformed to an active sulfonamide.

Ketotifen is a cycloheptathiophene blocker of histamine H1 receptors and release of inflammatory mediators. It has been proposed for the treatment of asthma, rhinitis, skin allergies, and anaphylaxis. Ketotifen was developed in 1970 by Sandoz Pharmaceuticals of Switzerland. It is a benzocycloheptathiophene derivative and was initially marketed as an inhibitor of anaphylaxis. The pharmacodynamic properties of ketotifen are many, because it is an inhibitor of the release and/or activity of mast cell and basophil mediators, including histamine, neutrophil, and eosinophil chemotactic factors, arachidonic acid metabolites, prostaglandins, and leukotrienes. Properties of ketotifen which may contribute to its antiallergic activity and its ability to affect the underlying pathology of asthma include inhibition of the development of airway hyper-reactivity associated with activation of platelets by PAF (Platelet Activating Factor), inhibition of PAF-induced accumulation of eosinophils and platelets in the airways, suppression of the priming of eosinophils by human recombinant cytokines and antagonism of bronchoconstriction due to leukotrienes. Ketotifen is marketed under many brand names worldwide. Ketotifen inhibits the release of mediators from mast cells involved in hypersensitivity reactions. Decreased chemotaxis and activation of eosinophils have also been demonstrated. Ketotifen also inhibits cAMP phosphodiesterase.

Naratriptan (trade names include Amerge and Naramig) is a triptan drug marketed by GlaxoSmithKline and is used for the treatment of migraine headaches.Naratriptan is a selective agonist of serotonin (5-hydroxytryptamine; 5-HT) type 1B and 1D receptors. It is structurally and pharmacologically related to other selective 5-HT1B/1D receptor agonist. Naratriptan has only a weak affinity for 5-HT1A, 5-HT5A, and 5-HT7 receptors and no significant affinity or pharmacological activity at 5-HT2, 5-HT3 or 5-HT4 receptor subtypes or at alpha1-, alpha2-, or beta-adrenergic, dopamine1,; dopamine2; muscarinic, or benzodiazepine receptors. This action in humans correlates with the relief of migraine headache. In addition to causing vasoconstriction, experimental data from animal studies show that Naratriptan also activates 5-HT1 receptors on peripheral terminals of the trigeminal nerve innervating cranial blood vessels, which may also contribute to the antimigrainous effect of Naratriptan in humans.Three distinct pharmacological actions have been implicated in the antimigraine effect of the triptans: (1) stimulation of presynaptic 5-HT1D receptors, which serves to inhibit both dural vasodilation and inflammation; (2) direct inhibition of trigeminal nuclei cell excitability via 5-HT1B/1D receptor agonism in the brainstem and (3) vasoconstriction of meningeal, dural, cerebral or pial vessels as a result of vascular 5-HT1B receptor agonism.

Telmisartan is an orally active nonpeptide angiotensin II antagonist that acts on the AT1 receptor subtype. It was discovered by Boehringer Ingelheim and launched in 1999 as Micardis. It has the highest affinity for the AT1 receptor among commercially available ARBS and has minimal affinity for the AT2 receptor. New studies suggest that telmisartan may also have PPARγ agonistic properties that could potentially confer beneficial metabolic effects, as PPARγ is a nuclear receptor that regulates specific gene transcription, and whose target genes are involved in the regulation of glucose and lipid metabolism, as well as anti-inflammatory responses. This observation is currently being explored in clinical trials. Angiotensin II is formed from angiotensin I in a reaction catalyzed by angiotensin-converting enzyme (ACE, kininase II). Angiotensin II is the principal pressor agent of the renin-angiotensin system, with effects that include vasoconstriction, stimulation of synthesis and release of aldosterone, cardiac stimulation, and renal reabsorption of sodium. Telmisartan works by blocking the vasoconstrictor and aldosterone secretory effects of angiotensin II. Telmisartan interferes with the binding of angiotensin II to the angiotensin II AT1-receptor by binding reversibly and selectively to the receptors in vascular smooth muscle and the adrenal gland. As angiotensin II is a vasoconstrictor, which also stimulates the synthesis and release of aldosterone, blockage of its effects results in decreases in systemic vascular resistance. Telmisartan does not inhibit the angiotensin converting enzyme, other hormone receptors, or ion channels. Studies also suggest that telmisartan is a partial agonist of PPARγ, which is an established target for antidiabetic drugs. This suggests that telmisartan can improve carbohydrate and lipid metabolism, as well as control insulin resistance without causing the side effects that are associated with full PPARγ activators. Used alone or in combination with other classes of antihypertensives for the treatment of hypertension. Telmisartan is used in the treatment of diabetic nephropathy in hypertensive patients with type 2 diabetes mellitus, as well as the treatment of congestive heart failure (only in patients who cannot tolerate ACE inhibitors).

Montelukast (SINGULAIR®) is a selective and orally active leukotriene D4 (LTD4) receptor antagonist that inhibits the cysteinyl leukotriene CysLT1 receptor. It is indicated for the prophylaxis and chronic treatment of asthma, for prevention of exercise-induced bronchoconstriction, and for the relief of symptoms of seasonal allergic rhinitis. LTD4 is a product of arachidonic acid metabolism and is released from various cells, including mast cells and eosinophils. This eicosanoid binds to CysLT1 receptor found in the human airway (including airway smooth muscle cells and airway macrophages) and on other pro-inflammatory cells (including eosinophils and certain myeloid stem cells). Cysteinyl leukotriene receptors (CysLTs) have been correlated with the pathophysiology of asthma and allergic rhinitis. In asthma, leukotriene-mediated effects include airway edema, smooth muscle contraction, and altered cellular activity associated with the inflammatory process. In allergic rhinitis, CysLTs are released from the nasal mucosa after allergen exposure during both earlyand late-phase reactions and are associated with symptoms of allergic rhinitis. Montelukast (SINGULAIR®) binds with high affinity and selectivity to the CysLT1 (in preference to other pharmacologically important airway receptors, such as the prostanoid, cholinergic, or beta-adrenergic receptor). It inhibits physiologic actions of LTD4 at the CysLT1 receptor without any agonist activity.

Candesartan is classified as an angiotensin II receptor type 1 antagonist. Candesartan is an orally active lipophilic drug and possesses rapid oral absorption. It causes a reduction in blood pressure and is used in the treatment of hypertension. It is also used in the treatment of congestive heart failure and given as prophylaxis to reduce the severity and duration of migraine. Candesartan cilexetil, a prodrug of Candesartan, is available in the market under the trade names Atacand, Amias. Candesartan cilexetil is rapidly converted to candesartan, its active metabolite, during absorption from the gastrointestinal tract. Candesartan confers blood pressure lowering effects by antagonizing the hypertensive effects of angiotensin II via the RAAS (renin–angiotensin–aldosterone system). RAAS is a homeostatic mechanism for regulating hemodynamics, water, and electrolyte balance. During sympathetic stimulation or when renal blood pressure or blood flow is reduced, renin is released from granular cells of the juxtaglomerular apparatus in the kidneys. Renin cleaves circulating angiotensinogen to angiotensin I, which is cleaved by angiotensin converting enzyme (ACE) to angiotensin II. Angiotensin II increases blood pressure by increasing total peripheral resistance, increasing sodium and water reabsorption in the kidneys via aldosterone secretion, and altering the cardiovascular structure. Angiotensin II binds to two receptors: type-1 angiotensin II receptor (AT1) and type-2 angiotensin II receptor (AT2). Candesartan selectively blocks the binding of angiotensin II to AT1 in many tissues including vascular smooth muscle and the adrenal glands. This inhibits the AT1-mediated vasoconstrictive and aldosterone-secreting effects of angiotensin II and results in an overall decrease in blood pressure. Candesartan is greater than 10,000 times more selective for AT1 than AT2.

Citalopram (brand names: Celexa, Cipramil, and others) is an antidepressant drug of the selective serotonin reuptake inhibitor (SSRI) class. It has U.S. Food and Drug Administration approval to treat major depression,[2]which it received in 1998, and is prescribed off-label for other conditions. In Australia, the UK, Germany, Portugal, Poland, and most European countries, it is licensed for depressive episodes and panic disorder with or without agoraphobia. In Spain, it is also used for obsessive-compulsive disorder. Citalopram HBr is a racemic bicyclic phthalane derivative designated (±)-1-(3-dimethylaminopropyl)-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5carbonitrile, HBr. The mechanism of action of citalopram HBr as an antidepressant is presumed to be linked to potentiation of serotonergic activity in the central nervous system (CNS) resulting from its inhibition of CNS neuronal reuptake of serotonin (5-HT). In vitro and in vivo studies in animals suggest that citalopram is a highly selective serotonin reuptake inhibitor (SSRI) with minimal effects on norepinephrine (NE) and dopamine (DA) neuronal reuptake. The single-and multiple-dose pharmacokinetics of citalopram are linear and dose-proportional in a dose range of 10-60 mg/day. Biotransformation of citalopram is mainly hepatic, with a mean terminal half-life of about 35 hours.

Rizatriptan (trade name Maxalt) is a 5-HT1 receptor agonist of the triptan class of drugs developed by Merck & Co. for the treatment of migraine headaches. Rizatriptan (trade name Maxalt) is a 5-HT1 receptor agonist of the triptan class of drugs developed by Merck & Co. for the treatment of migraine headaches. Rizatriptan acts as an agonist at serotonin 5-HT1B and 5-HT1D receptors. Rizatriptan binds with high affinity to human cloned 5-HT1B/1D receptors. Rizatriptan benzoate presumably exerts its therapeutic effects in the treatment of a migraine headache by binding to 5-HT1B/1D receptors located on intracranial blood vessels and sensory nerves of the trigeminal system. Rizatriptan is completely absorbed following oral administration. The mean oral absolute bioavailability of the rizatriptan benzoate tablet is about 45%, and mean peak plasma concentrations are reached in approximately 1-1.5 hours. The presence of a migraine headache did not appear to affect the absorption or pharmacokinetics of rizatriptan. Food has no significant effect on the bioavailability of rizatriptan but delays the time to reach peak concentration by an hour. The primary route of rizatriptan metabolism is via oxidative deamination by monoamine oxidase-A (MAO-A) to the indole acetic acid metabolite, which is not active at the 5-HT1B/1D receptor. N-mono-desmethyl-rizatriptan, a metabolite with activity similar to that of parent compound at the 5-HT1B/1D receptor, is formed to a minor degree. Plasma concentrations of N-mono-desmethyl-rizatriptan are approximately 14% of those of parent compound, and it is eliminated at a similar rate. Other minor metabolites, the N-oxide, the 6-hydroxy compound, and the sulfate conjugate of the 6-hydroxy metabolite are not active at the 5-HT1B/1D receptor.