Finasteride is a synthetic 4-azasteroid compound. This drug is a competitive and specific inhibitor of Type II 5a-reductase, an intracellular enzyme that converts the androgen testosterone into 5α-dihydrotestosterone (DHT). Two distinct isozymes are found in mice, rats, monkeys, and humans: Type I and II. Each of these isozymes is differentially expressed in tissues and developmental stages. In humans, Type I 5a-reductase is predominant in the sebaceous glands of most regions of skin, including scalp, and liver. Type I 5a-reductase is responsible for approximately one-third of circulating DHT. The Type II 5a-reductase isozyme is primarily found in prostate, seminal vesicles, epididymides, and hair follicles as well as liver, and is responsible for two-thirds of circulating DHT. Although finasteride is 100-fold more selective for type II 5a-reductase than for the type I isoenzyme, chronic treatment with this drug may have some effect on type I 5a-reductase. Finasteride is used for the treatment of symptomatic benign prostatic hyperplasia (BPH) in men with an enlarged prostate to: Improve symptoms, reduce the risk of acute urinary retention, reduce the risk of the need for surgery including transurethral resection of the prostate. Also used for the stimulation of regrowth of hair in men with mild to moderate androgenetic alopecia (male pattern alopecia, hereditary alopecia, common male baldness). Finasteride is sold under the brand names Proscar and Propecia among others.

Ondansetron (ZOFRAN®) is a selective 5-HT3 receptor antagonist. It is effective in the treatment of nausea and vomiting caused by radiotherapy, anesthesia, surgery or cytotoxic chemotherapy drugs, including cisplatin, and has reported anxiolytic and neuroleptic properties. While its mechanism of action has not been fully characterized, ondansetron is not a dopamine-receptor antagonist. It is not certain whether ondansetron's antiemetic action is mediated centrally, peripherally, or in both sites. However, cytotoxic chemotherapy appears to be associated with release of serotonin from the enterochromaffin cells of the small intestine. The released serotonin may stimulate the vagal afferents through the 5-HT3 receptors and initiate the vomiting reflex.

Clarithromycin is an antibacterial drug which is used either in combination with lansoprazole and amoxicillin (Prevpac), in combination with omeprazole and amoxicillin (Omeclamox) or alone (Biaxin) for the treatment of broad range of infections. The drug exerts its action by binding to 23s rRNA (with nucleotides in domains II and V). The binding leads to the protein synthesis inhibition and the cell death.

Sertraline (trade names Zoloft and others) is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. Sertraline is primarily prescribed for major depressive disorder in adult outpatients as well as obsessive-compulsive disorder, panic disorder, and social anxiety disorder, in both adults and children. The exact mechanism of action sertraline is not fully known, but the drug appears to selectively inhibit the reuptake of serotonin at the presynaptic membrane. This results in an increased synaptic concentration of serotonin in the CNS, which leads to numerous functional changes associated with enhanced serotonergic neurotransmission. It is suggested that these modifications are responsible for the antidepressant action observed during long-term administration of antidepressants. It has also been hypothesized that obsessive-compulsive disorder is caused by the dysregulation of serotonin, as it is treated by sertraline, and the drug corrects this imbalance. Compared to other SSRIs, sertraline tends to be associated with a higher rate of psychiatric side effects and diarrhea. It tends to be more activating (that is, associated with a higher rate of anxiety, agitation, insomnia, etc.) than other SSRIs, aside from fluoxetine. Over a two-week treatment of healthy volunteers, sertraline slightly improved verbal fluency but did not affect word learning, short-term memory, vigilance, flicker fusion time, choice reaction time, memory span, or psychomotor coordination. In spite of lower subjective rating, that is, feeling that they performed worse, no clinically relevant differences were observed in the objective cognitive performance in a group of people treated for depression with sertraline for 1.5 years as compared to healthy controls

Fosinopril is a phosphinic acid-containing ester prodrug that belongs to the angiotensin-converting enzyme (ACE) inhibitor class of medications. It is rapidly hydrolyzed to fosinoprilat, its principle active metabolite. Fosinoprilat inhibits ACE, the enzyme responsible for the conversion of angiotensin I (ATI) to angiotensin II (ATII). ATII regulates blood pressure and is a key component of the renin-angiotensin-aldosterone system (RAAS). Fosinopril may be used to treat mild to moderate hypertension, as an adjunct in the treatment of congestive heart failure, and to slow the rate of progression of renal disease in hypertensive individuals with diabetes mellitus and microalbuminuria or overt nephropathy.

Nabumetone is a naphthylalkanone. Is is a non-selective prostaglandin G/H synthase (a.k.a. cyclooxygenase or COX) inhibitor that acts on both prostaglandin G/H synthase 1 and 2 (COX-1 and -2). Prostaglandin G/H synthase catalyzes the conversion of arachidonic acid to prostaglandin G2 and prostaglandin G2 to prostaglandin H2. Prostaglandin H2 is the precursor to a number of prostaglandins involved in fever, pain, swelling, inflammation, and platelet aggregation. The parent compound is a prodrug that undergoes hepatic biotransformation to the active compound, 6-methoxy-2-naphthylacetic acid (6MNA). The analgesic, antipyretic and anti-inflammatory effects of NSAIDs occur as a result of decreased prostaglandin synthesis. The parent compound is a prodrug, which undergoes hepatic biotransformation to the active component, 6-methoxy-2-naphthylacetic acid (6MNA), that is a potent inhibitor of prostaglandin synthesis, most likely through binding to the COX-2 and COX-1 receptors. Nabumetone is used for acute and chronic treatment of signs and symptoms of osteoarthritis and rheumatoid arthritis. Nabumetone has been developed by Beecham. It is available under numerous brand names, such as Relafen, Relifex, and Gambaran.

Fluticasone propionate, a medium-potency synthetic corticosteroid, is used topically to relieve inflammatory and pruritic symptoms of dermatoses and psoriasis, intranasally to manage symptoms of allergic and non-allergic rhinitis, and orally for the treatment of asthma. Fluticasone proprionate is marketed under several different brand names such as Flonase®. Fluticasone propionate is also available as a combination product of azelastine hydrochloride and fluticasone propionate called Dymista™. Dymista™ is indicated in patients over 12 years old for symptomatic relief of seasonal allergic rhinitis. Fluticasone propionate binds to the glucocorticoid receptor. Unbound corticosteroids cross the membranes of cells such as mast cells and eosinophils, binding with high affinity to glucocorticoid receptors (GR). The results include alteration of transcription and protein synthesis, a decreased release of leukocytic acid hydrolases, reduction in fibroblast proliferation, prevention of macrophage accumulation at inflamed sites, reduction of collagen deposition, interference with leukocyte adhesion to the capillary wall, reduction of capillary membrane permeability and subsequent edema, reduction of complement components, inhibition of histamine and kinin release, and interference with the formation of scar tissue. In the management of asthma, the glucocorticoid receptor complexes down-regulates proinflammatory mediators such as interleukin-(IL)-1, 3, and 5, and up-regulates anti-inflammatory mediators such as IkappaB [inhibitory molecule for nuclear factor kappaB1], IL-10, and IL-12. The antiinflammatory actions of corticosteroids are also thought to involve inhibition of cytosolic phospholipase A2 (through activation of lipocortin-1 (annexin)) which controls the biosynthesis of potent mediators of inflammation such as prostaglandins and leukotrienes.

Clozapine was discovered in 1958 by an anesthetist and now it is used for the treatment of schizophrenia. Although the exact mechanism of its action is unknown, the effect of clozapine on schizophrenia is associated with inhibition of dopamine D2 and serotonin 2A receptors.

Selegiline, also known as L-deprenyl, is a substituted phenethylamine, a selective, irreversible inhibitor of Type B monoamine oxidase. Selegiline is available in pill form under many brand names (Eldepryl, Carbex, Atapryl) and is used to reduce symptoms in early-stage Parkinson's disease. Selegiline delays the time point when the L-DOPA (levodopa) treatment becomes necessary from about 11 months to about 18 months after diagnosis, which is beneficial despite not being definitive evidence of neuroprotection. The rationale for adding selegiline to levodopa is to decrease the required dose of levodopa and thus reduce the motor complications of levodopa therapy. Selegiline is also delivered via a transdermal patch (brand name, Emsam) and in this form, Selegiline is used as a treatment for the major depressive disorder. Selegiline (brand name Anipryl) is also used (at extremely high dosages relative to humans) in veterinary medicine to treat the symptoms of Cushing's disease and cognitive dysfunction (Canine Cognitive Dysfunction) in dogs. Side effects of the pill form include, in decreasing order of frequency, nausea, hallucinations, confusion, depression, loss of balance, insomnia, increased involuntary movements, agitation, arrhythmia, slow heart rate, delusions, hypertension, new or increased angina pectoris, and syncope. The main side effects of the patch form for depression included application site reactions, insomnia, diarrhea, and sore throat.

Clomipramine is an antidepressant drug which was approved by FDA for the treatment of Obsessive-Compulsive Disorder. The exact mechanism of its action is unknown, however it is supposed that it may exert its effect by inhibiting serotonin reuptake.