Medco Research Institute Study Finds Nearly One-Third of Antidepressant Dose Increases Prescribed for Patients with Poor Medication Adherence

- Patients exposed to higher risk of side effects

- Medication dose increases often tied to inconsistent use of antidepressants

Oct 15, 2010, 08:00 ET from Medco Health Solutions, Inc.

BOSTON, Oct. 15 /PRNewswire/ -- Nearly a third of all patients who are prescribed an increased dosage of antidepressants were not taking their original prescriptions regularly, according to new research conducted by the Medco Research Institute™, the research subsidiary of Medco Health Solutions, Inc. (NYSE: MHS).  The study was presented at the American Psychiatric Association's 62nd Institute on Psychiatric Services in Boston.



The study suggests that doctors should examine a patient's adherence to their antidepressant medications – meaning whether the patient is taking their medication consistently as directed – before raising the strength of the medication.  The research found sub-optimal medication adherence is a contributing factor to disease relapse and may lead to unnecessary increases in dosing.  Higher doses of antidepressants can worsen side-effects and also raise medication costs.

"A physician usually increases a dose when a patient is not responding to the current dosage.  But this analysis shows that the reason the dose may not be effective is that many patients are not taking their antidepressants as directed.  In this case, upping the dose may not remedy that issue," said Dr. David J. Muzina, National Practice Leader of the Medco Neuroscience Therapeutic Resource Center® (TRC) and lead author of the studies.  "Our data is showing us that lack of medication adherence is very common among patients. It's important that these adherence problems be identified and addressed to enable patients with depression to fully benefit from their medications."

The Medco Research Institute conducted this research through the Medco Neuroscience TRC, where pharmacists specialize in helping patients with behavioral health and neurological conditions. Medco's specialist pharmacists aim to optimize drug therapy effectiveness, maximize health outcomes by improving medication adherence, and help the patient avoid adverse effects from their medications.  

This study is one of many being conducted by the Medco Research Institute that examines patient behavior with chronic medications for opportunities to improve patient outcomes, ensure safety and reduce costs.

Antidepressant doses

Using Medco's database of medical and pharmacy claims for 13 million individuals, the study identified patients who were taking a specific dose of an antidepressant medication for at least 6 months before their doctor ordered an increased dose of that antidepressant, presumably due to clinical worsening of the condition being treated.  By examining pharmacy claims records over the 6-18 months prior to the increased dose order, investigators found that 29.7 percent of patients had been poorly adherent with the antidepressant.  

Poor adherence was defined by a medication possession ratio of less than 0.80, which suggests that a patient had been taking the antidepressant less than 80 percent of the time, judging by the frequency of prescription refills.  The study also showed a significantly higher medication adherence among patients filling their prescriptions through the Medco Pharmacy, where they have the opportunity to receive counseling from a Medco Neuroscience specialist pharmacist.

Antidepressant Side Effects  

Antidepressants have been shown to work in many clinical studies, but the drugs have side effects.  Also patients should talk to their doctors before cutting their dosage or stopping treatment, due to potential withdrawal symptoms.  Nausea and fatigue/drowsiness are common side effects during the first few weeks after starting treatment. Other common side effects include increased appetite/weight gain, anxiety, insomnia, dry mouth, blurred vision, constipation and sexual side effects.  

More information about this study can be found on

About Medco Research Institute

Medco Research Institute™ is an evidence-based research organization focused solely on novel research, analytics and new discoveries that close the gap between scientific discovery and medical practice for improved patient outcomes and lower overall healthcare costs. More information about the Medco Research Institute's peer-reviewed research can be found at

About Medco

Medco Health Solutions, Inc. (NYSE: MHS) is pioneering the world's most advanced pharmacy® and its clinical research and innovations are part of Medco making medicine smarter™ for approximately 65 million members.

With more than 20,000 employees dedicated to improving patient health and reducing costs for a wide range of public and private sector clients, and 2009 revenues of nearly $60 billion, Medco ranks 35th on the Fortune 500 list and is named among the world's most innovative, most admired and most trustworthy companies. For more information, go to

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SOURCE Medco Health Solutions, Inc.