BOSTON — A Methuen man has been arrested and charged with distributing fentanyl, a potentially lethal narcotic that has caused many deaths.

Alexsander Padro, 28, is accused of distributing more than 40 grams of the addictive drug, according to U.S. Attorney Andrew Lelling. Padro appeared in U.S. District Court on Thursday and was detained pending a hearing.

Padro sold more than 40 grams of fentanyl to a "cooperating source" at a restaurant in Methuen on Wednesday, Lelling said. It is also alleged that Padro sold fentanyl to an undercover officer on two occasions, 40 grams in March and $1,000 worth of the drug in April.

If he is convicted, Padro faces a mandatory minimum sentence of five years and up to 40 years in prison, a minimum of four years and up to a lifetime of supervised release and a fine of $5 million.

Lelling and Brian Boyle, special agent in charge of the Drug Enforcement Administration in New England, announced Padro's arrest Friday.

Assistant U.S. Attorney Bill Abely, deputy chief of the Major Crimes Unit of the U.S. Attorney's Office, is prosecuting the case.