Overprescribing opioid pain medications has contributed to a rise in opioid misuse and overdose deaths in the United States over the past two decades.

This has prompted many calls for doctors to be more cautious when writing opioid prescriptions, especially when dealing with toothaches, ankle sprains, and other less painful conditions and surgeries.

“Overall as a profession, we need to move away from using opioids for minor and self-limiting pain conditions,” said Dr. Anna Lembke, psychiatrist, and pain specialist at the Stanford University Medical Center.

New research reinforces this message, showing that even small amounts of opioids prescribed for pain can increase the chance that someone will still be refilling opioid prescriptions months later.

Read more: How surgery helped fuel the opioid epidemic »

Opioids for minor injuries increase risks

A recent study presented last month at the Society for Academic Emergency Medicine annual meeting in Orlando, Florida, focused on the risks of using opioids to treat pain from minor injuries, in this case ankle sprains.

Out of more than 53,000 patients who visited a U.S. emergency department for an ankle sprain from 2011 to 2012, 7 percent received a prescription for an opioid pain medication such as oxycodone or hydrocodone.

People who received 30 or more pills were twice as likely to fill another opioid prescription three to six months later, compared with people who were given less than 15 pills.

On average, doctors prescribed 20 pills to patients, but some patients received as many as 60 pills or more.

The results of the study have not been published yet in a peer-reviewed journal, so they should be viewed with some caution.

However, a study earlier this year conducted by the found that initial prescriptions may drive long-term opioid use.

Out of 1.2 million people who had at least one day of opioid therapy between 2006 and 2015, 6 percent were still taking opioids one year later.

The study included only opioid-naive people — those who hadn’t filled an opioid prescription within the previous year — who didn’t have cancer.

This increased to 13.5 percent for people whose first opioid dose was for eight or more days, and to almost 30 percent for people who started with at least a 31-day dose.

The CDC reported that around 7 percent of opioid prescriptions exceeded a one-month supply.

Starting treatment with a long-acting opioid increased the risk of long-term use — over 27 percent of these patients were still on opioids a year later, and over 20 percent were on them three years later.

Even patients who started on Tramadol — which Lembke said “was supposed to be a nonaddictive alternative” to other opioids — were at risk, with 13.7 percent still using opioids a year later.

Read more: Government taking action on opioid epidemic »

Initial prescriptions drive opioid use

Another study, published earlier this year in the Journal of General Internal Medicine, found similar results for people who had not used prescription opioids recently.

“The risks of long-term opioid use seemed to increase substantially even at fairly low doses and fairly low durations of therapy,” Dr. Richard A. Deyo, MPH, a family medicine physician, and a professor of evidence-based medicine at Oregon Health and Science University, told Healthline.

Researchers looked at over 530,000 opioid prescriptions filled in Oregon from 2012 to 2013 by opioid-naive patients.

People included in the study were not cancer or palliative care patients. Pain caused by these conditions is often treated with long-term prescription opioids.

Five percent of opioid-naive people became long-term users — filling six or more opioid prescriptions within the year following their initial prescription.

The risk of long-term opioid use was higher for people who filled a second prescription during the first month of treatment, as well as for those given a higher initial dose of opioids or a long-acting opioid medication.

The researchers pointed out that other factors may also contribute to long-term use. For example, doctors may prescribe long-term or higher-dose opioids to patients with “persistent and severe pain.”

And people at risk of opioid misuse — such as those with a past history of addiction or substance abuse — may be more likely to receive long-term opioids.

The CDC study also found that women were at higher risk of long-term opioid use, as well as those who had been diagnosed earlier with pain or were publicly insured or self-insured.

Read more: Prescription databases could reduce opioid misuse »

Lower and shorter opioid doses

, three days or less of prescription opioids are often “sufficient” for acute pain like an ankle sprain, with seven days “rarely” needed.

Some states have passed laws limiting how many opioid pills doctors can prescribe at a time to reduce the risk of prescription opioid abuse or people passing on their pills to others, which is known as “diversion.”

New Jersey has a five-day limit for first-time prescription opioid users, with exemptions for cancer, palliative, and hospice care patients.

The new studies are in line with this trend toward lower opioid dose and duration, and doctors relying more on prescription refills to treat ongoing pain.

“[Our results] really support the notion that we should be aiming low and short,” said Deyo, “and realize that anything beyond that is associated with the risk of long-term use.”

Deyo and colleagues wrote that initial prescriptions that fit these criteria might be “10 milligram hydrocodone tablets prescribed four times daily for three or fewer days” — so no more than 12 pills.

But even these smaller doses can pose a risk for some people.

“Somebody with a prior history of addiction — particularly to opioids and/or alcohol — can very quickly become addicted to even a one-week, or potentially even shorter, prescription,” said Lembke.

People who have never had problems with drugs or alcohol can also be susceptible.

“There are some individuals,” said Lembke, “who are vulnerable to addiction either by nature or nurture — or some combination — who even without a history of addiction can get addicted in a very short time.”

Read more: Rural America is suffering a health crisis »

Preventing opioid addiction

There are, of course, alternatives to opioid pain medications for acute pain, many of which have been around for a long time — like nonsteroidal anti-inflammatory drugs such as ibuprofen, Tylenol, and aspirin.

Some doctors are also experimenting with using local injections of anesthetics like lidocaine. This has the advantage of not flooding the entire body and brain with pain medication, like you get when you take a pill.

“What you do now is try to isolate the source of the pain with a lidocaine injection or infusion right where the injury is or where the surgery is going to take place,” said Lembke.

Studies such as these highlight the role that doctors can play in preventing prescription opioid misuse. Deyo and colleagues emphasize that doctors should realize they are dealing with “risky drugs, not risky patients.”

“It really does shift the responsibility more onto the clinician to be more cautious in prescribing these drugs,” said Deyo.

This approach also focuses more on stopping opioid abuse problems before they start.

Our paper tries to “shift people’s attention upstream a little bit towards preventing the emergence of long-term opioid problems,” said Deyo, “as opposed to focusing on people who are already having these problems.”