Beverly Hills, Calif. ? A judge issued an arrest warrant Monday for Lindsay Lohan after the actress acknowledged failing a drug test less than a month after she was released from inpatient rehab.

Superior Court Judge Elden Fox also revoked Lohan’s probation in her three-year-old drug case while issuing the bench warrant in Beverly Hills.

However, the warrant was stayed, and Lohan was allowed to remain free pending a hearing Friday to determine if she violated her probation.

Fox previously threatened the actress with 30 days in jail for each violation. He must now decide whether to send her back to jail or into treatment.

Also Monday, Lohan dropped her $100 million lawsuit over a Super Bowl ad for E-Trade that featured a “milkaholic” baby named Lindsay, according to documents filed Monday in a Manhattan court.

The actress withdrew her case against the brokerage, which she had claimed made her the implied target of the joke.

E-Trade Financial Corp. spokeswoman Susan Hickey said the case’s end reflected a “simple business decision” for the New York-based firm, but she wouldn’t discuss details.