PORTLAND, Maine — Portland police, fire and public health officials issued a warning about heroin use Thursday after seeing four overdoses and one suspected overdose fatality over a 24-hour period.

The four people who survived received life-saving emergency medical treatment Wednesday from the Portland Fire Department.

A fifth person was found dead in an East End apartment and his death is being investigated as a possible drug overdose, city officials said in a news release issued late Thursday afternoon.

City officials said that heroin use in Portland has increased dramatically in recent months. They said they believe that addicts are using heroin as a replacement for OxyContin.

“Testing of recent seizures of the drug does not indicate a higher than average potency, suggesting the problem is related to increased use,” they said, noting that heroin is a very addictive and dangerous drug.

In the past month, Portland police and fire personnel have responded to 14 reports of overdoses in which the patient survived after receiving emergency medical treatment.

“Tragically, three people died over the same period from what appear to be accidental drug overdoses. Most of these individuals were using heroin,” city officials said.

As a result of the spike in overdoses, the fire department has had to increase its supply of Naloxone, a narcotic antagonist that can reverse the respiratory depression associated with narcotic overdose.

From January to March of this year, Portland firefighters administered Naloxone 11 times. In April alone, they administered the drug 14 times.

Portland Public Health advises that to reduce the risk of overdose, individuals should:

• Not use the drug alone.

• Do a tester shot to gauge the drug’s strength.

• Avoid mixing drugs.

• Always use the recovery position, which involves lying on one’s side with one’s arms and upper leg at right angles to the body and one’s mouth pointed downward so fluid can drain.

• Dial 911. The window of treatment during an overdose is short and immediate treatment is critical for survival.

For help and access to drug treatment sources, call the statewide 24-hour Crisis Hotline at 888-568-1112.

To provide information anonymously to the Portland Police Department, contact the department by text, Internet or phone. Cellphone users can text the keyword “GOTCHA” plus their message to 274637 (CRIMES). To submit tips through the department’s website, go to www.portland-police.com and click ” Submit an Anonymous Crime Tip.” Anonymous phone tips can be left on the Crime Tip line at 874-8584.