Drugs took center stage Monday in the attempted murder trial of Matthew Buendia.

Buendia is the former Marine who is accused of shooting a Hillsborough County deputy.

Dr. Daniel Buffington testified Monday, listing 13 drugs that were prescribed to Buendia prior to Sept. 30. The medications were used for pain, panic attacks, depression, and skin conditions.

Those medications are: Dival Proex, Clonazapem, Mirtazapin, Ranitidine, Benzoyl peroxide, Clindamycin, Cyanocobalamin, Tramadol, Magnesium Oxide, Omeprazole, Meloxicam, Isotretinoin and Bupropion.

The list reveals the medication Buendia was supposed to be taking the day Hillsborough County Sheriff’s Deputy Lyonelle De Veaux was shot.

Buffington, a pharmacologist at the University of South Florida, testified about the medications and some possible side effects that come from the drugs.

"Problem behavior, disturbance in thinking, confusion," Buffington said.

Buendia's attorneys said it points to a sick ex-Marine who wasn't in his right mind when he shot the Hillsborough deputy, but prosecutors say they don't buy it.

"Is it possible that none of these drugs were affecting him in the way that was listed up there,” prosecutor Justin Diaz said. “Is that possible?"

"Absolutely possible," Buffington responded.

Buffington also testified that it is possible Buendia had not taken any of his prescription pills prior to the shooting.

Oxycodone and marijuana were found in Buendia's system, and hours before, Buendia had been drinking.

Prosecutors said that was not prescribed by doctors.

Those drugs, prosecutors believe, are the perfect combination for attempted murder.

The trial continues Tuesday. If convicted, Buendia could spend the rest of his life in prison.