Pharma reps, take heart. A new study finds that barring you from doctors' offices has some deleterious effects. It cut back on adoption of a brand-new, first-in-class diabetes drug--Merck's ($MRK) Januvia--which could be good for healthcare costs, but potentially kept patients from a therapy that might work better for them, the study authors concluded.

More worrisome, perhaps, were the rep-barring doctors' response to safety and efficacy questions. Physicians with the biggest barriers to reps were slow to respond to new safety warnings on GlaxoSmithKline's ($GSK) Avandia--back when those warnings were new, of course. These low-access doctors were not significantly slower, however, when it came to changing their prescribing habits after a study questioned the efficacy of Merck's combination cholesterol drug Vytorin.

The Journal of Clinical Hypertension noted that about 11% of U.S. doctors either bar reps completely or limit access considerably. Another 34% have some restrictions, such as requiring reps to make appointments. The biggest effect of sales-rep absence was found in primary-care doctors, the study authors noted.

Now, it could be that the practices barring reps are busy, leaving doctors little time to not only meet with pharma sales folks, but also to read journal articles and other materials. So, the slower uptake on Januvia and slower response to Avandia warnings could stem from that reading deficit as much as from the absence of reps. But there's no way to tell; this study didn't control for reading behavior. "We hope this study encourages other researchers to look more rigorously into this important drug policy and clinical practice matter," the authors conclude.