New uses for old drugs

In some cases, a new clinical activity observed for an old drug is sufficiently potent and interesting to justify the immediate use of the drug in the new indication, and this is illustrated below. 

Amiodarone, for example (Fig. 1.12), was introduced as a coronary dilator for angina, but concern about comeal deposits, discoloration of skin exposed to sunlight and thyroid disorders led to the withdrawal of the drug in 1967. However, in 1974 amiodarone was found to be highly effective in the treatment of a rare type of arrhythmia known as the Wolff-Parkinson-White syndrome. Accordingly, amiodarone was reintroduced specifically for that purpose [22]. 

Benziodarone was initially used in Europe as a coronary dilator, and proved later to be a useful uricosuric agent However, it is now withdrawn from the market due to several cases of jaundice associated with its use [22]. The corresponding brominated analogue, benzbromarone was specifically marketed for its uricosuric properties. 

Thalidomide was initially launched as a sedative/hypnotic drug (Fig. 1.13), but withdrawn because of its extreme teratogenicity. However, under restricted conditions (no administration during pregnancy, or to any woman of childbearing age), it found a new use as an immunomodulator. Thalidomide seems particularly effective in the treatment of erythema nodosum leprosum, a possible complication of the chemotherapy of leprosy [23]. 

In 2001, the antimalarial drug quinacrine and the antipsychotic drug chlorpro-mazine (Fig. 1.14) were shown to inhibit prion infection in cells. Pmsiner and coworkers [24] identified the drugs independently, and found that they inhibited the conversion of normal prion protein into infectious prions, and also cleared prions from infected cells. Both drugs can cross over from the bloodstream to the brain, where the prion diseases are localized. 

It is important to acknowledge that as we acquire additional experience with known drugs, new uses for existing agents are often identified. For example, it has recently been shown that the combination of the antibacterial antibiotic clindamycin (used clinically for years for its relatively 

---

In recent years, extensive use has been made of new formulations for old drugs, a good example being Alza s Concerta (methylphenidate, extended release Figure 1.22). This drug, used to treat Attention Deficit Hyperactivity Disorder (ADHD) in children and adolescents, uses sophisticated osmotic pressure delivery to maintain drug concentrations, with once a day (qd) dosing, at levels comparable with those observed with thrice daily... 

Vainio, H. and Morgan, G., Aspirin for the second hundred years new uses for an old drug, Pharmacol. 

R. Safirstein, L. Andrade, and J. M. Vieira Acetylcysteine and nephrotoxic effects of radiographic contrast agents—a new use for an old drug. The New England Journal of Medicine 343, 210 (2000). 

Americans consume an estimated 80 billion aspirin tablets each year. The Physicians Desk Reference lists more than 50 OTC drugs in which aspirin is the principal ingredient. Yet, despite the fact that aspirin has been in routine use for nearly a century, scientific journals continue to publish reports about new uses for this old remedy. 

D. Zhang, R. Yang, S. Wang and Z. Dongm, Paclitaxel New uses for an old drug. DrugDes. Devel.Ther.8 279-284,2014. 

Dear M. Sildenafil for hypertension Old drug, new use. Drug Topics 2005 Jul 11, http //www.drugtopics.com/drugtopics/article/articleDetail.jsp id=169471... 

---