She waited by the drugstore, Caesar had never been late before
Pharmaceutical companies are always on the lookout for secondary drug targets. After all, if you invest billions developing a single drug, you would be more than happy to sell it as a treatment for two, three, or more different ailments. Sildenafil citrate was developed to treat angina and hypertension. During phase I clinical trials, it was found that Sildenafil induces penile erections. The drug was branded Viagra, and the rest is history. Eflornithine, an anti-cancer drug, is also effective against the agent of African Sleeping Sickness, Trypanosoma brucei. African Sleeping Sickness belongs to a group of diseases known as “neglected diseases”, for which drug development is not profitable. However, having a drug already on hand makes it easier to market in affected areas.
Another example of polypharmacology is a drug that binds to multiple targets in the human body. This could be used for overcoming drug resistance, a known problem with cancer. Cancer tumours often develop a resistance to anti-cancer drugs because the protein that the drug bind to mutates, and no longer binds the drug. However, if the drug acts by binding redundantly to several proteins, it would be more effective, since several mutations would be required to effect drug resistance.
