A 26-year-old Madison man was sentenced Friday to eight years in prison after he admitted to being under the influence of several drugs at the time of a fatal crash.

Sean Monroe pleaded guilty to causing a death while operating a vehicle under the influence and reckless homicide, both Class C felonies.

The charges stem from a Jan. 28, 2013, accident in which Monroe crashed his vehicle into another car driven by 79-year-old Billy M. Deveary of Madison, who was killed in the accident.

A toxicology screening showed Monroe had amphetamine, methamphetamine, diazepam, nordiazepam, clonazepam, alprazolam, methadone and marijuana in his system on the day of the accident.

Vehicle event data recorders taken from Monroe's vehicle showed that he was traveling at more than 75 mph at the time of the crash.

Monroe will serve eight years in the Indiana Department of Correction, with no time suspended. Superior Court Judge Alison Frazier also ordered that Monroe spend the last year of his sentence in a therapeutic drug treatment program.

Jennifer Joas, Monroe's attorney, asked the judge to consider some suspended time in order to enter Monroe into drug treatment programs. Monroe testified that, prior to his arrest, he had abused prescription drugs every day since he was 18, adding that he was on his way to a methadone clinic in Jeffersonville on the day of the crash.

He told the court he has no recollection of the accident or taking drugs that day but admitted he had taken drugs the day before. He also apologized to the victim's family, who were in the courtroom.

Chief Deputy Prosecutor D.J. Mote presented evidence that showed Monroe later disputing the crash through a Facebook post. Monroe was not incarcerated at that time - his arrest came in May - because police were still investigating the incident.

Mote read the Facebook post, in which Monroe denied any fault and said "some old man" pulled out in front of him.

Mote said while Deveary did pull out in front of Monroe, an accident reconstruction report compiled by an independent agency showed that Monroe could have avoided that accident had he been going the posted speed limit of 45 mph.

The prosecutor's office also presented a sworn statement from a witness who identified Monroe as driving recklessly and swerving through traffic before the crash.

Mote said it "boggles the mind" to review the list of drugs found in Monroe's system that day, adding that someone under that level of drug influence and behind the wheel of a speeding vehicle is "everybody's worst nightmare."

Frazier said because of the aggravating circumstances - the victim's age, nature of the injuries and number of drugs in Monroe's system - she would not consider suspending any portion of the sentence.

Following the sentencing, Monroe said he plans to appeal the length of the sentence.