LA CROSSE, Wis. (WKBT) -

The La Crosse County Medical Examiner's Office says, there have been five drug overdose deaths in the last three weeks in La Crosse County.

Narcan continues to be an effective tool in reversing opioid overdoses, including heroin.

But more potent opioids may make Narcan less effective.

Synthetic drugs like fentanyl are in some cases 50-100 times stronger than heroin.

Doctors in our area say they have seen those types of opioids already, and it's only a matter of time before they become more widespread.

As a result, the new potent opioids will make Narcan less effective.

Doctors say the drug, which helps reverse the effects of an opioid overdose, have proven crucial in the battle against illegal drug use.

"It has made a huge difference in the number of patients we see, knowing there's a lot in the community that don't even come for medical services. They're treating themselves, and then surviving, and going about their life,” Dr. Chris Eberlein of Gundersen Health System said.

According to numbers from Gundersen Tri-State Ambulance, there have been 152 doses of Narcan administered to 105 patients through the first half of 2016.

If the trend holds, the number will be nearly 100 more than 2015.

"Just when we thought things were getting better, it's actually been getting worse,” Al Bliss, health educator for the La Crosse County Health Department, said.

As much as experts say Narcan is proving useful, drugs 50-100 times stronger than heroin are slowly becoming more prevalent in cities like Chicago.

"I think it's just a matter of time before it gets here,” Eberlein said.

The increase on those drugs will require more doses of Narcan, according to doctors.

"You're going to see people overdosing on these other, more potent opiates,” Eberlein said. “One, two, three, four, five doses of Narcan may not be enough to reverse it."

Despite what the future holds, doctors said there aren't any more available options.

"Sometimes it feels like we are chasing our tails, but it’s the best we can do right now,” Eberlein said. “We've got a serious opiate problem in the country, and we have to keep working to solve this issue."

Doctors say the shift to these more potent drugs may be because heroin is becoming harder to obtain.

Currently, the Heroin and Other Illicit Drug Task Force say it is in the early stages of trying to place drug drop boxes at the University of Wisconsin-La Crosse.

They say while not perfect, they hope recent legislation which increases access to Narcan will also continue to become crucial to help save lives.