Penicillamine (Cuprimine, Depen) - For when the copper is gettin' you down

• metabolite of penicillin, but is not an antibiotic since it lacks a beta-lactam ring
• discovered in 1953 in the urine of people with liver disease who were being given penicillin
• a fellow named John Walshe did some nifty experiments and figured out that it facilitated the excretion of copper via the urine, making it a useful agent for the treatment of Wilson's disease
• Wilson's disease is this genetic thing where people can't effectively rid themselves of copper, causing the metal to accumulate in the organs (e.g. brain and liver) and cause damage (e.g. dementia, mood disorders, Parkinson's-like symptoms, and hepatitis with cirrhosis developing over time)
• penicillamine functions as a chelating agent, meaning that it forms complexes with certain metal ions and promotes their elimination from the body via the urine
• used to treat the following:
• rheumatoid arthritis, scleroderma, and primary biliary cirrhosis (opens up a can of selective whoop-ass on your immune system)
• cystinuria (facilitates the elimination of cystine)
• mercury and lead poisoning (same valences as copper, yo)
• the aforementioned Wilson's disease (i.e. copper poisoning)
• only the D-isomer (get the lowdown on chirality) is used as a drug since the L-isomer can poison you by inhibiting the good stuff that vitamin B6 (pyridoxine) does

Goodman & Gilman's The Pharmacological Basis of Therapeutics - 11th Ed. (2006)