A study, which is being presented at the 2012 American Society for Clinical Pharmacology and Therapeutics (ASCPT) Annual Meeting, and conducted by the Medco Research Institute, claims that cancer drugs taken orally which hit enzymes in tumor cells may have been effective in the past for reducing the amount of time patients had to stay at centers to receive their chemotherapy, but new evidence shows that when they are taking other medicines, in addition to the oral cancer drugs, they negatively affect the efficacy of the cancer drug, or cause unwanted side effects. The authors determined that 23-74% of patients were taking 1 of 9 oral cancer drugs along with another medication which had the power to take away the strength of the cancer drug, and increase the dangers of it. The cancer drugs which the researchers studied are called oral kinase inhibitors. They included: imatinib (Gleevec®) erlotinib (Tarceva®) dasatinib (Sprycel®) everolimus (Afinitor®) lapatinib (Tykerb®) nilotinib (Tasigna®) pazopanib (Votrient®) sorafenib (Nexavar®) sunitinib (Sutent®) The medications that pose a threat to the effectiveness of oncology drugs are: calcium channel blockers some antibiotics antifungal agents steroids proton pump inhibitors Milayna Subar, national practice leader at the Medco Oncology Therapeutic Resource Center, said: \"Oral cancer drugs represent a huge advancement in oncology treatment, but make no mistake, these are powerful drugs. These cost medications can have severe side effects and need to be actively monitored for proper use and adherence. \"Whats as important is knowing what other medications the patient is on. The fact that about one quarter to 75 percent of patients on these oral drugs may not be getting the full benefit of their treatment or may in facet be putting their health at further the risk because of another medication they are taking is concerning. Our oncology pharmacists are able to alert doctors about potential medication interactions through our Drug Utilization Review programs that have a complete picture of their prescription drugs.\" To determine their findings, the researchers administered drugs which may affect the potential of the oral cancer drugs to 4,617 patients. 43% of them were given one which the authors believe would weaken the cancer medication, and 68% were given meds which raised the toxicity level of the treatment. Dr. Steve Bowlin, senior director and therapeutic areas research lead, MRI (Medco Research Institute), and co-author of the study said: \"Since these are drugs launched in the past decade for fairly small patient populations, we are learning more about how they are used in real-world settings as compared to traditional clinical trials that test safety and efficacy in a tightly-controlled environment. Oncologists are not always aware of other medications prescribed by other doctors and vice-versa, which can pose a real hazard for their patients on oral cancer therapies.\" Over the last 10 years, oral cancer drugs have sky-rocketed to the status of being effective in treating many types of cancers and have fewer side effects than chemotherapy. They have been known to turn terminal cases of cancer into not-so-horrible ones, which can be helped with drugs. Dr. Eric Stanek, vice president of research at MRI, and co-author of the study concluded: \"Complex medication regimens can raise the odds of drug interactions, and we are finding that many drugs prescribed to cancer patients share genetically-determined metabolism and transport pathways that may affect response to cancer treatment and merit additional study. \"As we learn more about how to optimize treatment with cancer drugs, we are in a better position to share this knowledge with our patients and other clinicians through our Therapeutic Resource Centers, which can alert clinicians to these potential interactions, and so we can collaborate with them to seek therapeutic alternatives with less interaction potential whenever possible.\"