Sulfiram (also known as monosulfiram) is a sulfide derivative patented by L. Givaudan & Cie. S. A. as effective anti-parasitic medicine used for the treatment and prevention of scabies and other skin related problems like itching, skin irritation, and inflammation. Sulfiram is a very weak inhibitor of aldehyde dehydrogenase. Sulfiram is usually sold as a solution or medicated soap, sometimes in combination with benzyl benzoate. Sulfiram is now rarely used, but, as of 2015, is still available in Brazil, India, and South Africa.

Pipradimadol is a 4.4-disubstituted piperidine derivative which demonstrates, in animal experiments, effects typical for certain antidepressant and antiserotonin drugs. Pipradimadol is the central serotonin antagonist. Pipradimadol exhibits antinociceptive properties also. Behavioral tests reflect overall sedation after pipradimadol, decreased rectal temperature and locomotor activity; cataleptic effects of tetrabenazine are antagonized and noradrenaline as well as dopamine reuptake in vitro are slightly inhibited. Homovanillic acid, a metabolite of dopamine is strongly increased after pipradimadol in rat striatum. Pipradimadol was used as analgesic agent.

Piriprost (U-60, 257) is a structural analog of prostaglandin I2 (PGI2) with low IP receptor-mediated activity. It inhibits 5-LO (5-lipoxygenase). Piriprost inhibits the release of histamine and leukotrienes, implicating its role in inflammation and allergic responses. However, it was shown, that piriprost did not influence the airway responses after allergen in asthma. Nevertheless, even more, the drug was irritant to the respiratory tract than was placebo.

Yohimbinic acid, also known as yohimbic acid is an indole alkaloid, which was isolated from dried roots of Rauwolfia serpentina. Yohimbinic acid is a potent inhibitor of a human DNA Topoisomerase I and can inhibit cancer cells growth.

Safingol, the synthetic L-threo-stereoisomer of endogenous (D-erythro-) sphinganine, is an inhibitor of protein kinase C and sphingosine kinase in vitro, and in some cell types has been implicated in ceramide generation and induction of apoptosis. Safingol inhibits enzymatic activity and 3H-phorbol dibutyrate binding of purified rat brain PKC (IC50 = 37.5 uM and 31uM, respectively). Inhibits human PKCα, the major overexpressed isoenzyme in MCF-7 DOXR cells (IC50 = 40 uM). Safingol enhances the cytotoxic effect of the chemotherapeutic agent Mitomycin C (MMC) in gastric cancer cells by promoting drug-induced apoptosis. Safingol is an inhibitor of SphK (Sphingosine kinase). Safingol has been shown to act synergistically with other chemotherapeutic agents and may potentiate chemotherapy drug-induced apoptosis in vitro and in vivo.

Orazipone (also known as OR-1384 or OR-1958) was developed by Orion Company as thiol-modulating, anti-inflammatory agent. Orazipone inhibits activation of inflammatory transcription factors nuclear factor-kappa B and signal transducer and activator of transcription 1 and decreases inducible nitric-oxide synthase expression and nitric oxide production in response to inflammatory stimuli. This drug had completed phase I clinical studies in Finland for possible use in inflammatory bowel disease, asthma, and chronic obstructive pulmonary disease. In addition, orazipone was studied for the treatment of Crohn's disease. However, all these studies were discontinued.

OPINIAZIDE (also known as saluzid) was used for the treatment of meningeal tuberculosis in adults and in children. Information about the current use of this drug is not available.

Omidoline, an antiparkinsonian agent that has never been marketed. Information about the current use of this drug is not available.

Pidobenzone, an amino acid ester of hydroquinone, is a second-generation worldwide patented depigmenting agent, reliable and free of collateral risks. Pidobenzone 4% lipogel represents a useful, reliable, and safe treatment of the different types of melasma. No data are available regarding the efficacy of pidobenzone as monotherapy for solar lentigines. The combination of cryotherapy and pidobenzone 4% has been found to be the most useful treatment of solar lentigines and the prevention of eventual posttreatment hyperchromia.