Mequinol (mequinol is 4-hydroxyanisole) is an active ingredient in topical drugs used for skin depigmentation. The mechanism of action of mequinol is unknown. Although mequinol is a substrate for the enzyme tyrosinase and acts as a competitive inhibitor of the formation of melanin precursors, the clinical significance of these findings is unknown.

Beclometasone dipropionate or beclomethasone dipropionate is sold under the brand name Qvar among others. Beclomethasone dipropionate is a corticosteroid demonstrating potent anti-inflammatory activity. The precise mechanism of corticosteroid action on asthma is not known. Corticosteroids have been shown to have multiple anti-inflammatory effects, inhibiting both inflammatory cells (e.g., mast cells, eosinophils, basophils, lymphocytes, macrophages, and neutrophils) and release of inflammatory mediators (e.g., histamine, eicosanoids, leukotrienes, and cytokines). These anti-inflammatory actions of corticosteroids may contribute to their efficacy in asthma. Beclomethasone dipropionate is a prodrug that is rapidly activated by hydrolysis to the active monoester, 17 monopropionate (17-BMP). Beclomethasone 17 monopropionate has been shown in vitro to exhibit a binding affinity for the human glucocorticoid receptor, which is approximately 13 times that of dexamethasone, 6 times that of triamcinolone acetonide, 1.5 times that of budesonide and 25 times that of beclomethasone dipropionate. The clinical significance of these findings is unknown. Studies in patients with asthma have shown a favorable ratio between topical anti-inflammatory activity and systemic corticosteroid effects with recommended doses of QVAR. Beclometasone dipropionate was first patented in 1962 and used medically in 1972. Common side effects with the inhaled form include respiratory infections, headaches, and throat inflammation. Serious side effects include an increased risk of infection, cataracts, Cushing’s syndrome, and severe allergic reactions. Long term use of the pill form may cause adrenal insufficiency. The pills may also cause mood or personality changes. The inhaled form is generally regarded as safe in pregnancy. Beclometasone is mainly a glucocorticoid.

Etretinate (trade name Tegison) is a medication developed by Hoffmann–La Roche that was approved by the FDA in 1986 to treat severe psoriasis. It is a second-generation retinoid. It was subsequently removed from the Canadian market in 1996 and the United States market in 1998 due to the high risk of birth defects. Etretinate remains on the market in Japan as Tigason. The mechanism of action of etretinate is still incompletely understood although, like retinoic acid, it is thought to interfere with the terminal differentiation of keratinocytes. Etretinate activates retinoid receptors, causing an induction of cell differentiation, inhibition of cell proliferation, and inhibition of tissue infiltration by inflammatory cells.

Octinoxate, also called Octyl methoxycinnamate or (OMC), is a UV filter. It can be absorbed rapidly through skin.Octinoxate filters UV‐B rays from the sun, although it does not protect against UV-A rays. Octinoxate dissolves in oil, which makes it a fat-seeking substance in the body. It is formed by combining methoxycinnamic acid and 2-ethylhexanol compounds which are not harmful on their own. When mixed together, they form a clear liquid that does not dissolve in water. Octinoxate is found in hair color products and shampoos, sunscreen, lipstick, nail polish, and skin creams. In products other than sunscreens, it is used as a UV filter to protect the products from degrading when exposed to the sun.

Meclocycline is a tetracycline antibiotic. It is used topically for skin infections treatment. Tetracyclines are broad-spectrum bacteriostatic agents and act by inhibiting protein synthesis by blocking the binding of aminoacyl tRNA (transfer RNA) to the mRNA (messenger RNA) ribosome complex. Meclocycline might increase sensitivity to light when it is used with Aminolevulinic acid.

Triclosan was used as a hospital scrub in the 1970s. Since then, it has expanded commercially and is now prevalent in soaps (0.10-1.00%), shampoos, deodorants, toothpastes, mouth washes, cleaning supplies and pesticides. It is part of consumer products, including kitchen utensils, toys, bedding, socks and trash bags. In healthcare, triclosan is used in surgical scrubs and hand washes. Use in surgical units is effective with a minimum contact time of approximately two minutes. More recently, showering with 2% triclosan has become a recommended regimen in surgical units for the decolonization of patients whose skin carries methicillin-resistant Staphylococcus aureus (MRSA). Triclosan is also used in the coatings for some surgical sutures. Triclosan has been employed as a selective agent in molecular cloning. At high concentrations, triclosan acts as a biocide with multiple cytoplasmic and membrane targets. However, at the lower concentrations seen in commercial products, triclosan appears bacteriostatic, and it targets bacteria primarily by inhibiting fatty acid synthesis. Triclosan binds to bacterial enoyl-acyl carrier protein reductase (ENR) enzyme, which is encoded by the gene FabI. This binding increases the enzyme's affinity for nicotinamide adenine dinucleotide (NAD+). This results in the formation of a stable, ternary complex of ENR-NAD+-triclosan, which is unable to participate in fatty acid synthesis. Fatty acids are necessary for building and reproducing cell membranes. Humans do not have an ENR enzyme and thus are not affected.

Flumethasone or flumetasone is a corticosteroid and is an agonist of a glucocorticoid receptor with anti-inflammatory, antipruritic and vasoconstrictive properties. Flumethasone is often formulated as the pivalic acid ester, flumetasone pivalate. The immune system is suppressed by corticosteroids due to a decrease in the function of the lymphatic system, a reduction in immunoglobulin and complement concentrations, the precipitation of lymphocytopenia, and interference with antigen-antibody binding. Flumethasone binds to plasma transcortin, and it becomes active when it is not bound to transcortin. Flumethasone is used for the treatment of contact dermatitis, atopic dermatitis, exczema, psoriasis, diaper rash and other skin condition.

Thiabendazole (TBZ, trade names Mintezol, Tresaderm, and Arbotect) was first introduced in 1962. This drug is a fungicide and parasiticide and is indicated for the treatment of: strongyloidiasis (threadworm), cutaneous larva migrans (creeping eruption), visceral larva migrans, trichinosis: relief of symptoms and fever and a reduction of eosinophilia have followed the use of this drug during the invasion stage of the disease. But usage of this drug was discontinued. The precise mode of action of thiabendazole on the parasite is unknown, but it may inhibit the helminthspecific enzyme fumarate reductase. It was shown, also that thiabendazole reversibly disassembles newly established blood vessels, marking it as vascular disrupting agent (VDA) and thus as a potential complementary therapeutic for use in combination with current anti-angiogenic therapies. Was shown, that vascular disruption by TBZ results from reduced tubulin levels and hyper-active Rho signaling. In addition, was confirmed, that thiabendazole slowed tumor growth and decreased vascular density in preclinical fibrosarcoma xenografts and thus, it could lead directly to the identification of a potential new therapeutic application for an inexpensive drug that is already approved for clinical use in humans.

Beta-carotene is found in many foods and is sold as a dietary supplement. Beta-carotene is a carotenoid, weak antioxidant; precursor of vitamin A, which is essential for vision and growth. Used to reduce the severity of photosensitivity reactions in patients with erythropoietic protoporphyria (EPP). Has been used in high-dose antioxidant supplements containing ascorbic acid and vitamin E with zinc in high-risk patients with age-related macular degeneration. Beta-carotene is also used to decrease asthma symptoms caused by exercise; to prevent certain cancers, heart disease, cataracts; and to treat AIDS, alcoholism, Alzheimer’s disease, depression, epilepsy, headache, heartburn, high blood pressure, infertility, Parkinson’s disease, rheumatoid arthritis, schizophrenia, and skin disorders including psoriasis and vitiligo.

Trioxsalen (trimethylpsoralen, trioxysalen or trisoralen) is a furanocoumarin and a psoralen derivative. It is obtained from several plants, mainly Psoralea corylifolia. Like other psoralens it causes photosensitization of the skin. It is administered either topically or orally in conjunction with UV-A (the least damaging form of ultraviolet light) for phototherapy treatment of vitiligo1 and hand eczema.2 After photoactivation it creates interstrand cross-links in DNA, which can cause programmed cell death unless repaired by cellular mechanisms. In research it can be conjugated to dyes for confocal microscopy and used to visualize sites of DNA damage.3 The compound is also being explored for development of antisense oligonucleotides that can be cross-linked specifically to a mutant mRNA sequence without affecting normal transcripts differing at even a single base pair.Trioxsalen was discontinued by the manufacturer in December 2002.