Following the Rx to the Letter – or Not

Prescription medications not taken as directed for majority of patients

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Patients may not always follow the instructions their doctors provide for prescription medications. In fact, more than half of Americans in a recent study did not.

A report conducted by a lab testing company found that about 60 percent of patients were not taking their medications as prescribed by their doctors.

In addition, about a quarter of all patients had marijuana detected in their urine. About a third were using the medications they had been prescribed as well as other medications they had not been prescribed.

"Follow your doctor's instructions for taking all medications."

The study, conducted by Quest Diagnostics, a lab testing company, involved analyzing the lab results for urine specimens from 227,402 individuals throughout all of 2011 and 2012.

These individuals were age 10 or older and were from all but one state in the US. The samples included labs ordered by family doctors, internists, specialists and hospital staff to test for use of prescription medications. The samples tested by drug rehabilitation clinics were not included in the analysis.

The analysis revealed that approximately 60 percent of patients had not taken their prescription medications according to the instructions provided by the doctor who ordered the lab in 2012. In 2011, 63 percent did not correctly follow the instructions for prescription medication use.

The Quest analysis determined if patients followed instructions based on whether the test results were consistent or inconsistent.

Only 40 percent of the test results in this sample were consistent in 2012, indicating the percentage of patients who complied with the instructions of their doctors.

Among the inconsistent results in 2012, 25 percent tested positive for a medication, but not the one prescribed. Among the same group, 33 percent tested positive for their prescribed medications as well as others not prescribed, and 42 percent did not have any medications in their urine, which means they were not taking their prescribed medications at all. The numbers were similar for 2011.

These numbers were also similar for both men and women and across all different age groups.

The most commonly found drug in patients' urine samples that was not prescribed by the doctor was marijuana, which was identified in 26 percent of the patients' samples.

The other most commonly found medications in the urine samples were painkillers: 22 percent had opiates detected in their urine, 16 percent had benzodiazepines, 14 percent had oxycodone, 8 percent had cocaine and 6 percent had methadone.

Among the patients with marijuana in their urine samples, 45 percent also used other medications they had not been prescribed, primarily sedatives and narcotic pain killers. Approximately a quarter of marijuana users (25 percent) had oxazepam in their urine, 20 percent had temazepam, 19 percent had hydromorphone and 17 percent had alpha-hydroxyalprazolam.

Among patients without marijuana detected in their urine, just over a third (36 percent) of the patients had these non-prescribed medications in their samples.

These findings imply that marijuana users may also be more likely to combine their cannabis use with other drug abuse, the Quest report stated. However, those who used marijuana were no more or less likely to skip using their prescribed medications.

The report was released by Quest Diagnostics Health Trends on April 4.

Reviewed by: 
Review Date: 
April 3, 2013
Last Updated:
April 5, 2013