Dextromethorphan is a non-narcotic morphine derivative widely used as an antitussive for almost 40 years. It has attracted attention due to its anticonvulsant and neuroprotective properties. It is a cough suppressant in many over-the-counter cold and cough medicines. In 2010, the FDA approved the combination product dextromethorphan/quinidine for the treatment of pseudobulbar affect. Dextromethorphan suppresses the cough reflex by a direct action on the cough center in the medulla of the brain. Dextromethorphan shows high-affinity binding to several regions of the brain, including the medullary cough center. This compound is an NMDA receptor antagonist and acts as a non-competitive channel blocker. It is one of the widely used antitussives and is used to study the involvement of glutamate receptors in neurotoxicity. Dextromethorphan (DM) is a sigma-1 receptor agonist and an uncompetitive NMDA receptor antagonist. The mechanism by which dextromethorphan exerts therapeutic effects in patients with pseudobulbar affect is unknown. Dextromethorphan should not be taken with monoamine oxidase inhibitors due to the potential for serotonin syndrome. Dextromethorphan is extensively metabolized by CYP2D6 to dextrorphan, which is rapidly glucuronidated and unable to cross the blood-brain barrier.

Caffeine is a methylxanthine alkaloid found in the seeds, nuts, or leaves of a number of plants native to South America and East Asia that is structurally related to adenosine and acts primarily as an adenosine receptor antagonist with psychotropic and anti-inflammatory activities. Upon ingestion, caffeine binds to adenosine receptors in the central nervous system (CNS), which inhibits adenosine binding. This inhibits the adenosine-mediated downregulation of CNS activity; thus, stimulating the activity of the medullary, vagal, vasomotor, and respiratory centers in the brain. The anti-inflammatory effects of caffeine are due the nonselective competitive inhibition of phosphodiesterases. Caffeine is used by mouth or rectally in combination with painkillers (such as aspirin and acetaminophen) and a chemical called ergotamine for treating migraineheadaches. It is also used with painkillers for simple headaches and preventing and treating headaches after epidural anesthesia. Caffeine creams are applied to the skin to reduce redness and itching in dermatitis. Healthcare providers sometimes give caffeine intravenously (by IV) for headache after epidural anesthesia, breathing problems in newborns, and to increase urine flow. In foods, caffeine is used as an ingredient in soft drinks, energy drinks, and other beverages.

Codeine is an opiate used to manage mild to moderate pain severe enough to require an opioid. Codeine is a selective agonist for the mu opioid receptor and has an affinity to delta and kappa-opioid receptors. In some countries, this drug is regulated under various narcotic control laws, because its chronic use can cause physical dependence. In others, it is available without a medical prescription in combination with paracetamol.

Menthyl lactate is derived from menthol, a compound that comes from peppermint oil, or is made synthetically. Menthol has a natural cooling effect, which makes it useful as a topical analgesic to treat skin irritation, pain, itching or sunburn. Despite its cooling benefits, menthol can be a skin irritant. Like menthol, menthyl lactate is cooling, but it causes less skin irritation than menthol. Menthyl lactate also has a refreshing, minty taste. For this reason, some manufacturers use it as a flavoring ingredient. The compound is recommended for use as a flavor in concentrations of 0.005% to 0.2% and in cosmetic and other external products in concentrations ranging from 0.2% to 2.0%. Menthyl lactate is a known compound available e.g. from Haarmann & Reimer GmbH (Germany) under the name FRESCOLAT, Type ML.

Tartaric acid is found in many plants such as grapes, tamarinds, pineapples, mulberries and so on. Wine lees (called mud in the US), the sediment collected during the fermentation of grapes, contains potassium bitartrate (potassium hydrogen tartrate) as its major component. L-(+)-tartaric acid is an enantiomer of tartaric acid. Twenty five years before the tetrahedral structure for carbon was proposed in 1874 to explain the optical activity and other properties of organic compounds, Louis Pasteur discovered the existence of enantiomerism in tartaric acid. L-(+)-tartaric acid is widely used in food and beverage as acidity regulator with E number E334.

Thiorphan is the first potent synthetic inhibitor of enkephalinase. Thiorphan displays antinociceptive activity after systemic administration. Thiorphan also inhibits to a lesser extent the widely distributed angiotensin-converting enzyme, a carboxydipeptidase implicated in blood pressure regulation. Thiorphan failed to potentiate allergen-induced airway responses in asthma. Thiorphan significantly reduced the castor oil-induced diarrhea in rats when administered intravenously but not when administered intracerebroventricularly. Racecadotril, via its active metabolite thiorphan, was consistently effective in animal models and patients with various forms of acute diarrhea by inhibiting pathologic (but not basal) secretion from the gut without changing gastro-intestinal transit time or motility.

Etanidazole (also known as Radinyl) is a 2-nitroimidazole with radiosensitizing properties. Etanidazole exerts its therapeutic action by depleting glutathione and inhibiting glutathione S-transferase, thus enhancing the anticancer effects of radiation therapy. Etanidazole was tested in Phase III clinical trials in patients with advanced head and neck cancer, however, its development was stopped. A fluorinated etanidazole (EF5) may also be useful as an imaging agent for identification of hypoxic, drug-resistant regions of primary tumors and metastases.

Exisulind (tentative trade name Aptosyn) is an antineoplastic agent, which was originally developed by Cell Pathways. This drug is an inhibitor of phosphodiesterase (PDE) isozymes: PDE5 and PDE4. Inhibition of PDE5 appears to be pharmacologically relevant, which leads to increase cGMP and activate protein kinase G at doses that induce apoptosis, whereas cyclic AMP levels were not changed. Exisulind has been in phase III clinical trials for the treatment of Non-Small Cell Lung Cancer and for the treatment of polyps in patients who have familial adenomatous polyposis (Colorectal Cancer and Small Intestine Cancer). In addition, this drug was in phase II/III for the treatment of Prostate Cancer, however, there studies have been discontinued.

Etazolate (EHT-0202) is a selective, positive GABAA receptor modulator has completed phase II clinical trials in patients with Alzheimer's disease. It is also a selective phosphodiesterase-4 inhibitor that is specific for cAMP. Etazolate showed anxiolytic and antidepressant activity and could be useful in managing post-traumatic stress disorder.

Tarenflurbil (Flurizan or R-flurbiprofen) is the single enantiomer of the racemate NSAID flurbiprofen. Tarenflurbil is a first in class, selective amyloid-beta42 (A42) lowering agent (SALA), which acts by modulating the activity of gamma-secretase, an enzyme that converts amyloid precursor protein to amyloid-beta. The reduction of A42 may prevent the development of the amyloid plaques thought to be a key pathological process associated with Alzheimer’s disease. For several years, research and trials for the drug were conducted by Myriad Genetics, to investigate its potential as a treatment for Alzheimer's disease. In a brief statement issued June 30, Myriad Genetics reports that tarenflurbil (Flurizan) failed to have a significant effect in a phase 3 trial of patients with mild Alzheimer's disease (AD). The failure of Flurizan™ is generally attributed to its insufficient pharmacodynamics, i.e., inadequate ability to penetrate the brain and engage its target protein at doses sufficient to yield an effect. Two additional Phase 3 trials were terminated and further development of Flurizan™ was discontinued. Separate clinical development of Flurizan™ for prostate cancer has also been discontinued following negative Phase 2 results. Tarenflurbil activates c-Jun N terminal kinase, increases AP-1 binding to DNA, and downregulates cyclin D1 expression, resulting in the arrest of tumour cells in the G1 phase of the cell cycle and apoptosis. This agent also affects the expression of nuclear factor kappa B, a rapid response transcription factor that stimulates the immune response to tumour cells. Tarenflurbil does not inhibit the enzyme cyclooxygenase. The Fraunhofer Institute for Molecular Biology and Applied Ecology is currently developing tarenflurbil for the treatment of relapsing, remitting multiple sclerosis.