Diazepam is a benzodiazepine first discovered at Hoffman-La Roche in the late 1950s. Diazepam was approved by FDA for the treatment of anxiety disorders as well as for such conditions as skeletal muscle spasm, alcohol withdrawal syndrom and convulsions (under the most known brand Valium). The drug acts by binding to GABA-A receptors and potentiating GABA evoked current. Chronic diazepam use is associated with tolerance, dependence, and withdrawal.

Metaxalone (marketed by King Pharmaceuticals under the brand name Skelaxin) is a muscle relaxant used to relax muscles and relieve pain caused by strains, sprains, and other musculoskeletal conditions. The mechanism of action of metaxalone in humans has not been established, but may be due to general central nervous system depression. Metaxalone has no direct action on the contractile mechanism of striated muscle, the motor end plate, or the nerve fiber. Skelaxin is available in an 800 mg scored tablet. Metaxalone relatively low incidence of side effects. The most common adverse reactions to Metaxalone tablets include drowsiness, dizziness, headache, and nervousness or “irritability”, nausea, vomiting, gastrointestinal upset.

Tegafur (INN, BAN, USAN) is a chemotherapeutic fluorouracil prodrug used in the treatment of cancers. It is a component of the combination drugs tegafur/uracil and tegafur/gimeracil/oteracil. UFT is an anticancer medication composed of a fixed molar ration (1:4) of tegafur and uracil. This drug is commonly used in the treatment of head and neck cancer, gastric cancer, colorectal cancer, hepatic cancer, gallbladder cancer, bile-duct cancer, pancreatic cancer, lung cancer, breast cancer, bladder cancer, prostatic cancer, or uterine cervical cancer. In the body, tegafur is converted into 5-fluorouracil (5-FU), the active antineoplastic metabolite. The mechanism of cytotoxicity of 5-FU is thought to be derived from the fact that 5-fluoro-deoxyuridine-monophosphate (FdUMP), the active metabolite of 5-FU, competes with deoxyuridine-monophosphate (dUMP), thereby inhibiting thymidylate synthase and subsequently DNA synthesis. Another active metabolite of 5-FU, 5-fluorouridine-triphosphate (FUTP) is integrated into cellular RNA, inhibiting RNA function. Uracil, when combined with tegafur, enhances the antitumor activity of 5-FU due to higher 5-FU concentrations in the tumor tissue versus normal surrounding tissue compared with tegafur alone. Uracil inhibits degradation of the released 5-FU. The combination of these two drugs enhances the antitumor activity of Tegafur.

Glycopyrrolate is a synthetic anticholinergic agent with a quaternary ammonium structure. Glycopyrrolate is a muscarinic competitive antagonist used as an antispasmodic, in some disorders of the gastrointestinal tract, and to reduce salivation with some anesthetics. Glycopyrrolate binds competitively to the muscarinic acetylcholine receptor. Like other anticholinergic (antimuscarinic) agents, it inhibits the action of acetylcholine on structures innervated by postganglionic cholinergic nerves and on smooth muscles that respond to acetylcholine but lack cholinergic innervation. These peripheral cholinergic receptors are present in the autonomic effector cells of smooth muscle, cardiac muscle, the sinoatrial node, the atrioventricular node, exocrine glands and, to a limited degree, in the autonomic ganglia. Thus, it diminishes the volume and free acidity of gastric secretions and controls excessive pharyngeal, tracheal, and bronchial secretions. Glycopyrrolate antagonizes muscarinic symptoms (e.g., bronchorrhea, bronchospasm, bradycardia, and intestinal hypermotility) induced by cholinergic drugs such as the anticholinesterases. The highly polar quaternary ammonium group of glycopyrrolate limits its passage across lipid membranes, such as the blood-brain barrier, in contrast to atropine sulfate and scopolamine hydrobromide, which are highly non-polar tertiary amines which penetrate lipid barriers easily. Glycopyrrolate is marketed under the brand names Robinul, Robinul Forte, Cuvposa. In October 2015, glycopyrrolate was approved by the FDA for use as a standalone treatment for Chronic obstructive pulmonary disease (COPD), as Seebri Neohaler.

Medroxyprogesterone acetate (INN, USAN, BAN), also known as 17α-hydroxy-6α-methylprogesterone acetate, and commonly abbreviated as MPA, is a steroidal progestin, a synthetic variant of the human hormone progesterone. Medroxyprogesterone acetate (MPA) administered orally or parenterally in the recommended doses to women with adequate endogenous estrogen, transforms proliferative into secretory endometrium. Androgenic and anabolic effects have been noted, but the drug is apparently devoid of significant estrogenic activity. While parenterally administered MPA inhibits gonadotropin production, which in turn prevents follicular maturation and ovulation, available data indicate that this does not occur when the usually recommended oral dosage is given as single daily doses. MPA is a more potent derivative of its parent compound medroxyprogesterone (MP). While medroxyprogesterone is sometimes used as a synonym for medroxyprogesterone acetate, what is normally being administered is MPA and not MP. Used as a contraceptive and to treat secondary amenorrhea, abnormal uterine bleeding, pain associated with endometriosis, endometrial and renal cell carcinomas, paraphilia in males, GnRH-dependent forms of precocious puberty, as well as to prevent endometrial changes associated with estrogens. Progestins diffuse freely into target cells in the female reproductive tract, mammary gland, hypothalamus, and the pituitary and bind to the progesterone receptor. Once bound to the receptor, progestins slow the frequency of release of gonadotropin releasing hormone (GnRH) from the hypothalamus and blunt the pre-ovulatory LH surge.

Diclorphenamide, a carbonic anhydrase inhibitor, was initially developed for the treatment of glaucome, however, now it is used for patients suffering from primary hypokalemic and hyperkalemic periodic paralysis. The exact mechanism of diclorphenamide in periodic paralysis is unknown.

Hydroxychloroquine possesses antimalarial properties and also exerts a beneficial effect in lupus erythematosus (chronic discoid or systemic) and acute or chronic rheumatoid arthritis. Although the exact mechanism of action is unknown, it may be based on ability of hydroxychloroquine to bind to and alter DNA. Hydroxychloroquine has also has been found to be taken up into the acidic food vacuoles of the parasite in the erythrocyte. This increases the pH of the acid vesicles, interfering with vesicle functions and possibly inhibiting phospholipid metabolism. In suppressive treatment, hydroxychloroquine inhibits the erythrocytic stage of development of plasmodia. In acute attacks of malaria, it interrupts erythrocytic schizogony of the parasite. Its ability to concentrate in parasitized erythrocytes may account for their selective toxicity against the erythrocytic stages of plasmodial infection. As an antirheumatic, hydroxychloroquine is thought to act as a mild immunosuppressant, inhibiting the production of rheumatoid factor and acute phase reactants. It also accumulates in white blood cells, stabilizing lysosomal membranes and inhibiting the activity of many enzymes, including collagenase and the proteases that cause cartilage breakdown. Hydroxychloroquine is used for the suppressive treatment and treatment of acute attacks of malaria due to Plasmodium vivax, P. malariae, P. ovale, and susceptible strains of P. falciparum. It is also indicated for the treatment of discoid and systemic lupus erythematosus, and rheumatoid arthritis.

Dapsone was synthesized in 1908 by Fromm and Wittmann. The drug was approved by FDA for the treatment of such conditions as acne vulgaris, leprosy and dermatitis herpetiformis, also the drug is used off-label for many skin diseases. Although the exact mechanism of dapsone action is unknown, it is speculated that it acts as both anti-inflammatory and antimicrobial agent. It was demonstrated that dapsone suppresses ROS generation, inhibits neutrophil myeloperoxidase and eosinophil peroxidase and also inhibits bacterial dihydropteroate synthase.

Warfarin is an anticoagulant drug normally used to prevent blood clot formation as well as migration. Warfarin is marketed under the brand name Coumadin among others. Coumadin (crystalline warfarin sodium) is an anticoagulant which acts by inhibiting vitamin K-dependent coagulation factors. Chemically, it is 3-(α-acetonylbenzyl)-4-hydroxycoumarin and is a racemic mixture of the R- and S-enantiomers. Coumadin is indicated for the prophylaxis and/or treatment of venous thrombosis and its extension, and pulmonary embolism. It is also indicated for the prophylaxis and/or treatment of the thromboembolic complications associated with atrial fibrillation and/or cardiac valve replacement. Warfarin is thought to interfere with clotting factor synthesis by inhibition of the C1 subunit of the vitamin K epoxide reductase (VKORC1) enzyme complex, thereby reducing the regeneration of vitamin K1 epoxide. The degree of depression is dependent upon the dosage administered and, in part, by the patient’s VKORC1 genotype. Therapeutic doses of warfarin decrease the total amount of the active form of each vitamin K dependent clotting factor made by the liver by approximately 30% to 50%.

Ethinyl estradiol is a synthetic derivative of the natural estrogen estradiol. It is one of two estrogens currently used in oral contraceptive pills. The other, mestranol, is converted to ethinyl estradiol before it is biologically active. Ethinyl estradiol and norethindrone are used together as an oral contraceptive agent. Estrogens diffuse into their target cells and interact with a protein receptor. Target cells include the female reproductive tract, the mammary gland, the hypothalamus, and the pituitary. Estrogens increase the hepatic synthesis of sex hormone binding globulin (SHBG), thyroid-binding globulin (TBG), and other serum proteins and suppress follicle-stimulating hormone (FSH) from the anterior pituitary. This cascade is initiated by initially binding to the estrogen receptors. The combination of an estrogen with a progestin suppresses the hypothalamic-pituitary system, decreasing the secretion of gonadotropin-releasing hormone (GnRH). Used for treatment of moderate to severe vasomotor symptoms associated with the menopause, female hypogonadism, prostatic carcinoma-palliative therapy of advanced disease, breast cancer, as an oral contraceptive, and as emergency contraceptive.