I. Definition and Nomenclature
II. Functions
III. P-450s Regulation
IV. P-450s and Cardiovascular Drug Interactions
GLOSSARY
antiarrhythmic agents cardioactive drugs used to prevent and
treat arrhythmias. myopathy disease of muscle. rhabdomyolysis disintegration of striated muscle fibers with
excretion of myoglobin in the urine. xenobiotic compound that is foreign to the body, such as a drug
or an environmental pollutant.
THE CYTOCHROME P-450 (CYP450) METABOLIC pathway is involved in the metabolism of many cardio¬vascular medications. Many significant drug interactions often involve this pathway.

• I. DEFINITION AND NOMENCLATURE
  Cytochrome P-450 refers to a colored substance in the cell that absorbs light at around 450 nm within the visible spectrum. The word cyto means cell and chrome means color. The P in P-450 refers to pigment and the 450 refers to its wavelength.
• II. FUNCTIONS
  The human cytochrome P-450 superfamily is comprised of 57 genes. Cytochrome P-450s use electrons from nicotinamide adenine dinucleotide (NADH) and oxy¬gen to oxidize their substrates. These genes code for enzy¬mes that have a role in many metabolic processes including:
• III. P-450s REGULATION
  Human P-450s that metabolize foreign chemicals are virtually all in the CYP1, CYP2, CYP3, and CYP4 families. P-450s are regulated by a number of xenobiotics and the cellular content of a P-450 is elevated by the same compound that it metabolizes. This induction of P-450s by various compounds is known to advance via a receptor-mediated mechanism.
• IV. P-450s AND CARDIOVASCULAR DRUG INTERACTIONS
  The induction of P-450s has implications for significant cardiovascular drug interactions including statins and beta-adrenergic blocking agents.
• BIBLIOGRAPHY
  Farmer, J. A. Learning from the cerivastatin experience. Lancet,