Nitisinone, 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC) is a triketone with herbicidal activity. Orfadin® capsules contain nitisinone used in the treatment of hereditary tyrosinemia type 1 (HT-1). Nitisinone is a competitive inhibitor of 4-hydroxyphenyl-pyruvate dioxygenase, an enzyme upstream of fumarylacetoacetase in the tyrosine catabolic pathway. By inhibiting the normal catabolism of tyrosine in patients with HT-1, nitisinone prevents the accumulation of the catabolic intermediates maleylacetoacetate and fumarylacetoacetate. In patients with HT-1, these catabolic intermediates are converted to the toxic metabolites succinylacetone and succinylacetoacetate, which are responsible for the observed liver and kidney toxicity. Succinylacetone can also inhibit the porphyrin synthesis pathway leading to the accumulation of 5-aminolevulinate, a neurotoxin responsible for the porphyric crises characteristic of HT-1. Zeneca Agrochemicals and Zeneca Pharmaceuticals made NTBC available for clinical use and, with the approval of the Swedish Medical Products Agency, a seriously ill child with an acute form of tyrosinaemia type 1 was successfully treated in February 1991. Nitisinone is investigated as a potential treatment for other disorders of tyrosine metabolism including alkaptonuria.

Ketorolac is a pyrrolizine carboxylic acid derivative structurally related to indomethacin. It is an NSAID and is used principally for its analgesic activity and has been shown to decrease opioid requirements in post-operative patients. It does not affect consciousness or respiration but does have effects on gastric mucosa, renal perfusion, and platelet function. Ketorolac tromethamine ophthalmic solution is sold under brand name acular LS and is indicated for the reduction of ocular pain and burning/stinging following corneal refractive surgery. Ketorolac tromethamine is a racemic mixture of [-]S- and [ ]R-enantiomeric forms, with the S-form having analgesic activity. Its antiinflammatory effects are believed to be due to inhibition of both cylooxygenase-1 (COX-1) and cylooxygenase-2 (COX-2) which leads to the inhibition of prostaglandin synthesis leading to decreased formation of precursors of prostaglandins and thromboxanes from arachidonic acid. The resultant reduction in prostaglandin synthesis and activity may be at least partially responsible for many of the adverse, as well as the therapeutic, effects of these medication. Analgesia is probably produced via a peripheral action in which blockade of pain impulse generation results from decreased prostaglandin activity.

Dexketoprofen is a nonsteroidal anti-inflammatory drug (NSAID), manufactured by Menarini under the tradename Keral. Dexketoprofen is indicated for short-term treatment of mild to moderate pain, including dysmenorrhoea. Dexketoprofen works by blocking the action of a substance in the body called cyclo-oxygenase, which is involved in the production of chemicals in the body called prostaglandins. Prostaglandins are produced in response to injury or certain diseases and would otherwise go on to cause swelling, inflammation, and pain. By blocking cyclo-oxygenase, dexketoprofen prevents the production of prostaglandins and therefore reduces inflammation and pain. Along with peripheral analgesic action, it possesses central analgesic action. Dexketoprofen may cause dizziness, and patients should not, therefore, drive or operate heavy machinery or vehicles until they are familiar with how dexketoprofen affects them. Concomitant use of alcohol and other sedatives may potentiate this effect. In a small subset of individuals, the dizziness may be intolerable and require the transition to an alternative treatment.

Mebendazole, known as Emverm is a (synthetic) broad-spectrum anthelmintic that acts by interfering with carbohydrate metabolism and inhibiting polymerization of microtubules. The loss of the cytoplasmic microtubules leads to impaired uptake of glucose by the larval and adult stages of the susceptible parasites, and depletes their glycogen stores. Degenerative changes in the endoplasmic reticulum, the mitochondria of the germinal layer, and the subsequent release of lysosomes result in decreased production of adenosine triphosphate (ATP), which is the energy required for the survival of the helminth. Due to diminished energy production, the parasite is immobilized and eventually dies. Emverm tablets are used for the treatment of Enterobius vermicularis (pinworm), Trichuris trichiura (whipworm), Ascaris lumbricoides (common roundworm), Ancylostoma duodenale (common hookworm), Necator americanus (American hookworm) in single or mixed infections. All metabolites are devoid of anthelmintic activity. In man, approximately 2% of administered mebendazole is excreted in urine and the remainder in the feces as unchanged drug or a primary metabolite. Preliminary evidence suggests that cimetidine inhibits mebendazole metabolism and may result in an increase in plasma concentrations drug. Mebendazole sometimes causes diarrhea, abdominal pain, and elevated liver enzymes. In rare cases, it has been associated with a dangerously low white blood cell count, low platelet count, and hair loss, with a risk of agranulocytosis in rare cases

Benzonatate is an antitussive that is FDA approved for the symptomatic relief of cough. It acts peripherally by anesthetizing the stretch receptors located in the respiratory passages, lungs, and pleura by dampening their activity and thereby reducing the cough reflex at its source. Common adverse reactions include nausea, oral hypoesthesia, throat symptom, numbness, dizziness, headache, sedation, somnolence. Benzonatate is chemically related to anesthetic agents of the para-amino-benzoic acid class (e.g. procaine; tetracaine) and has been associated with adverse CNS effects possibly related to a prior sensitivity to related agents or interaction with concomitant medication.

Methotrexate is an antineoplastic anti-metabolite. Anti-metabolites masquerade as purine or pyrimidine - which become the building blocks of DNA. They prevent these substances becoming incorporated in to DNA during the "S" phase (of the cell cycle), stopping normal development and division. Methotrexate inhibits folic acid reductase which is responsible for the conversion of folic acid to tetrahydrofolic acid. At two stages in the biosynthesis of purines and at one stage in the synthesis of pyrimidines, one-carbon transfer reactions occur which require specific coenzymes synthesized in the cell from tetrahydrofolic acid. Tetrahydrofolic acid itself is synthesized in the cell from folic acid with the help of an enzyme, folic acid reductase. Methotrexate looks a lot like folic acid to the enzyme, so it binds to it quite strongly and inhibits the enzyme. Thus, DNA synthesis cannot proceed because the coenzymes needed for one-carbon transfer reactions are not produced from tetrahydrofolic acid because there is no tetrahydrofolic acid. Methotrexate selectively affects the most rapidly dividing cells (neoplastic and psoriatic cells). Methotrexate is indicated in the treatment of gestational choriocarcinoma, chorioadenoma destruens and hydatidiform mole. In acute lymphocytic leukemia, methotrexate is indicated in the prophylaxis of meningeal leukemia and is used in maintenance therapy in combination with other chemotherapeutic agents. Methotrexate is also indicated in the treatment of meningeal leukemia. Methotrexate is used alone or in combination with other anticancer agents in the treatment of breast cancer, epidermoid cancers of the head and neck, advanced mycosis fungoides (cutaneous T cell lymphoma), and lung cancer, particularly squamous cell and small cell types. Methotrexate is also used in combination with other chemotherapeutic agents in the treatment of advanced stage non-Hodgkin’s lymphomas. Methotrexate is indicated in the symptomatic control of severe, recalcitrant, disabling psoriasis. Methotrexate is indicated in the management of selected adults with severe, active rheumatoid arthritis (ACR criteria), or children with active polyarticular-course juvenile rheumatoid arthritis.

Leucovorin is a compound similar to folic acid, which is a necessary vitamin. It has been around and in use for many decades. Leucovorin is a medication frequently used in combination with the chemotherapy drugs fluoruracil and methotrexate. Leucovorin is not a chemotherapy drug itself, however it is used in addition to these chemotherapy drugs to enhance anticancer effects (with fluorouracil) or to help prevent or lessen side effects (with methotrexate). Leucovorin is also used by itself to treat certain anemia problems when folic acid deficiency is present.

Levoleucovorin is the pharmacologically active isomer of leucovorin or 5-formyl tetrahydrofolic acid, a folate analog . Levoleucovorin does not require reduction by the enzyme dihydrofolate reductase in order to participate in reactions utilizing folates as a source of “onecarbon” moieties. Administration of levoleucovorin can counteract the therapeutic and toxic effects of folic acid antagonists such as methotrexate, which act by inhibiting dihydrofolate reductase. Levoleucovorin can enhance the therapeutic and toxic effects of fluoropyrimidines used in cancer therapy such as 5-fluorouracil. 5-fluorouracil is metabolized to 5-fluoro-2'-deoxyuridine-5'-monophosphate (FdUMP), which binds to and inhibits thymidylate synthase (an enzyme important in DNA repair and replication). Levoleucovorin is readily converted to another reduced folate, 5,10-methylenetetrahydrofolate, which acts to stabilize the binding of FdUMP to thymidylate synthase and thereby enhances the inhibition of this enzyme. Fusilev® (levoleucovorin) is approved by FDA for i) rescue after high-dose methotrexate therapy in osteosarcoma, ii) diminishing the toxicity and counteracting the effects of impaired methotrexate elimination and of inadvertent overdosage of folic acid antagonists and iii) in combination chemotherapy with 5-fluorouracil in the palliative treatment of patients with advanced metastatic colorectal cancer.

Folic Acid is a B complex vitamin containing a pteridine moiety linked by a methylene bridge to para-aminobenzoic acid, which is joined by a peptide linkage to glutamic acid. Conjugates of Folic Acid are present in a wide variety of foods, particularly liver, kidneys, yeast and leafy green vegetables. Commercially available Folic Acid is prepared synthetically. Folic Acid occurs as a yellow or yellowish-orange crystalline powder and is very slightly soluble in water and insoluble in alcohol. Aqueous solutions of Folic Acid are heat sensitive and rapidly decompose in the presence of light and/or riboflavin; solutions should be stored in a cool place protected from light. Folic Acid is effective in the treatment of megaloblastic anemias due to a deficiency of Folic Acid (as may be seen in tropical or nontropical sprue) and in anemia of nutritional origin, pregnancy, infancy, or childhood. Folic Acid is relatively nontoxic in man. Rare instances of allergic responses to Folic Acid preparations have been reported and have included erythema, skin rash, itching, general malaise, and respiratory difficulty due to bronchospasm. Endocyte is developing an intravenous (IV) formulation of folic acid, called Neocepri®, which is intended for the diagnosis of positive folate receptor-positive status in patients with ovarian cancer when administered prior to the radioactive medicine, technetium Tc99m Etarfolatide. The benefits of Neocepri® are its ability to reduce the background activity observed on single photon emission computed tomography (SPECT) imaging in most normal, nontarget tissues (e.g. intestines, liver, kidney, spleen), thereby improving the image quality of the scans. The product had been granted orphan drug designation in the EU. Endocyte had filed a conditional marketing authorization application (CMA) with the European Medicines Agency (EMA) for Neocepri®.

Benzoic acid is a natural ingredient occurring in many foodstuffs and in plant extracts. Benzoic acid, its salts and esters are used as preservatives in cosmetic products, with a maximum concentration of 0.5 %. Benzoic acid and sodium benzoate are on the FDA list of substances that are generally recognized as safe (GRAS). Both may be used as antimicrobial agents, flavouring agents and as adjuvants with a current maximum level of 0.1% in food. Benzoic acid is a constituent of Whitfield Ointment, which is used for the treatment of fungal skin diseases such as tinea, ringworm, and athlete's foot. Adverse effect of Whitfield Ointment: occasionally, a localized mild inflammatory response occurs.