Aldose reductase inhibitors are a class of drugs being studied as a way to prevent eye and nerve damage in people with diabetes.
Trimethoprim (TMP) is an antibiotic used mainly in the treatment of bladder infections. Other uses include for middle ear infections and travelers' diarrhea. With sulfamethoxazole or dapsone it may be used for Pneumocystis pneumonia in people with HIV/AIDS. It is taken by mouth.
Dihydrotestosterone is an endogenous androgen sex steroid and hormone. The enzyme 5α-reductase catalyzes the formation of DHT from testosterone in certain tissues including the prostate gland, seminal vesicles, epididymides, skin, hair follicles, liver, and brain. This enzyme mediates reduction of the C4-5 double bond of testosterone. DHT may also be synthesized via the ‘androgen backdoor pathway’ in the absence of Testosterone. Relative to testosterone, DHT is considerably more potent as an agonist of the androgen receptor (AR).
Cerivastatin is a synthetic member of the class of statins used to lower cholesterol and prevent cardiovascular disease. It was marketed by the pharmaceutical company Bayer A.G. in the late 1990s, competing with Pfizer's highly successful atorvastatin (Lipitor). Cerivastatin was voluntarily withdrawn from the market worldwide in 2001, due to reports of fatal rhabdomyolysis.
Finasteride, sold under the brand names Proscar and Propecia among others, is a medication used to treat hair loss and benign prostatic hyperplasia (BPH) in men. It can also be used to treat excessive hair growth in women. It is taken orally.
5α-Reductases, also known as 3-oxo-5α-steroid 4-dehydrogenases, are enzymes involved in steroid metabolism. They participate in three metabolic pathways: bile acid biosynthesis, androgen and estrogen metabolism. There are three isozymes of 5α-reductase encoded by the genes SRD5A1, SRD5A2, and SRD5A3.
5α-Reductase inhibitors (5-ARIs), also known as dihydrotestosterone (DHT) blockers, are a class of medications with antiandrogenic effects which are used primarily in the treatment of enlarged prostate and scalp hair loss. They are also sometimes used to treat excess hair growth in women and as a component of hormone therapy for transgender women.
3-Aminopyridine-2-carboxaldehyde thiosemicarbazone is a substance that is being studied in the treatment of cancer.
Dutasteride, sold under the brand name Avodart among others, is a medication primarily used to treat the symptoms of a benign prostatic hyperplasia (BPH), an enlarged prostate not associated with cancer. A few months may be required before benefits occur. It is also used for scalp hair loss in men and as a part of hormone therapy in transgender women. It is usually taken by mouth.
4-Hydroxycoumarins belong to a class of vitamin K antagonist (VKA) anticoagulant drug molecules derived from coumarin by adding a hydroxy group at the 4 position to obtain 4-hydroxycoumarin, then adding a large aromatic substituent at the 3-position. The large 3-position substituent is required for anticoagulant activity.
Mexazolam is a drug which is a benzodiazepine derivative. Mexazolam has been trialed for anxiety and was found to be effective in alleviating anxiety at one week follow-up. Mexazolam is metabolised via the CYP3A4 pathway. HMG-CoA reductase inhibitors including simvastatin, simvastatin acid, lovastatin, fluvastatin, atorvastatin and cerivastatin inhibit the metabolism of mexazolam, but not the HMG-CoA reductase inhibitor pravastatin. Its principal active metabolites are chlordesmethyldiazepam and chloroxazepam.
Cycloguanil is a dihydrofolate reductase inhibitor, and is a metabolite of the antimalarial drug proguanil; its formation in vivo has been thought to be primarily responsible for the antimalarial activity of proguanil. However, more recent work has indicated that, while proguanil is synergistic with the drug atovaquone, cycloguanil is in fact antagonistic to the effects of atovaquone, suggesting that, unlike cycloguanil, proguanil may have an alternative mechanism of antimalarial action besides dihydrofolate reductase inhibition.
Epalrestat is a carboxylic acid derivative and a noncompetitive and reversible aldose reductase inhibitor used for the treatment of diabetic neuropathy, which is one of the most common long-term complications in patients with diabetes mellitus. It reduces the accumulation of intracellular sorbitol which is believed to be the cause of diabetic neuropathy, retinopathy and nephropathy It is well tolerated, with the most commonly reported adverse effects being gastrointestinal issues such as nausea and vomiting, as well as increases in certain liver enzymes. Chemically, epalrestat is unusual in that it is a drug that contains a rhodanine group. Aldose reductase is the key enzyme in the polyol pathway whose enhanced activity is the basis of diabetic neuropathy. Aldose reductase inhibitors (ARI) target this enzyme. Out of the many ARIs developed, ranirestat and fidarestat are in the trial stage. Others have been discarded due to unacceptable adverse effects or weak efficacy. Epalrestat is the only ARI commercially available. It is easily absorbed into the neural tissue and inhibits the enzyme with minimum side effects.
Ribonucleotide reductase inhibitors are a family of anti-cancer drugs that interfere with the growth of tumor cells by blocking the formation of deoxyribonucleotides.
Glucogallin is chemical compound formed from gallic acid and β-D-glucose. It can be found in oaks species like the North American white oak, European red oak and Amla fruit.
Epristeride, sold under the brand names Aipuliete and Chuanliu, is a medication which is used in the treatment of enlarged prostate in China. It is taken by mouth.
11β-Methyl-19-nortestosterone (11β-MNT) is a synthetic and orally active anabolic–androgenic steroid (AAS) and a derivative of nandrolone (19-nortestosterone) which was developed by the Contraceptive Development Branch (CDB) of the National Institute of Child Health and Human Development (NICHD) and has not been marketed at this time.
MK-386, also known as 4,7β-dimethyl-4-aza-5α-cholestan-3-one, is a synthetic, steroidal 5α-reductase inhibitor which was first reported in 1994 and was never marketed. It is a 4-azasteroid and a potent and selective inhibitor of 5α-reductase type I and shows high selectivity for inhibition of human 5α-reductase type I over 5α-reductase type II, with IC50 values of 0.9 nM and 154 nM, respectively. The drug was under investigation for potential treatment of androgen-dependent conditions such as acne and pattern hair loss (androgenic alopecia or baldness), but was discontinued in early clinical trials due to observations of hepatotoxicity such as elevated liver enzymes.
This article is about the discovery and development of 5α-reductase inhibitors (5-ARIs), also known as dihydrotestosterone (DHT) blockers.
MK-434 is a 5α-reductase inhibitor which was under development in the 1990s by Merck & Co for the treatment of a variety of androgen-dependent conditions including benign prostatic hyperplasia, prostate cancer, pattern hair loss, excessive hair growth, acne, and seborrhea but was never marketed. It acts as a selective inhibitor of 5α-reductase type 2. The drug has been found to decrease circulating dihydrotestosterone levels by a maximum of approximately 50% in men. MK-434 is a synthetic 4-azasteroid and is structurally related to other 5α-reductase inhibitors like finasteride.
