Filed at 2:34 p.m. ET

KANSAS CITY, Mo. (AP) -- The pharmacist accused of endangering lives by watering down cancer drugs pleaded guilty Tuesday to all 20 federal counts in an agreement with the government that avoids a trial.

Millionaire pharmacist Robert R. Courtney, shackled at the hands and ankles, admitted that he committed 158 separate dilutions of drugs for 34 patients, and apologized to them in court.

Courtney, 49, had been scheduled to go to trial March 11 on the charges of adulterating, tampering with and mislabeling the chemotherapy drugs Taxol and Gemzar.

Under the plea agreement, prosecutors will recommend a sentence of 17 1/2 to 30 years in federal prison. If he had gone to trial and been convicted on all counts, Courtney could have been sentenced to 196 years in prison.

Courtney must disclose any other criminal activity he committed and any knowledge he possesses of crimes by others. If the government believes he has been truthful, he will not face any other charges.

Court records had indicated that the U.S. attorney's office was seeking additional charges, which could have been filed as early as Tuesday.

U.S. District Judge Ortrie Smith asked Courtney if he understood the plea he was entering.

``I've done this strictly voluntarily,'' Courtney replied. ``I've talked to my family and I've talked to my attorneys.''

Assistant U.S. Attorney Gene Porter presented evidence of the dilutions in the 34 cases -- eight detected by laboratory tests and 26 Courtney described in a written confession.

In a statement that brought many in the courtroom to tears, Courtney apologized to the victims, their families and his family, saying he had no ``rational explanation'' for his actions.

``I have had a long period of time in isolation to reflect on my conduct,'' said Courtney, who struggled several times to maintain his composure. ``I am guilty and I accept full responsibility. To the victims, I am extremely sorry.''

Barbara Wibbenmeyer, a cancer patient from Kansas City who has filed a civil lawsuit against Courtney, called the plea agreement ``probably the best thing we can do for the victims at this point. It starts putting closure to the `wheres' and the `whens.'''

``If they do give him 30 years, I'd like to see my mug shot on his wall for the rest of his life,'' said Wibbenmeyer, 47. ``I think he needs to see me.''

Courtney has been jailed since he surrendered to the FBI on Aug. 15.

Authorities have not said how many patients affected by the dilutions have died.

Criminal law experts have said prosecutors would have faced daunting obstacles in building a provable case that a cancer patient would have lived if the medication hadn't been altered.

Spectators in the packed courtroom included Courtney's wife as well as relatives of cancer patients who believe they received diluted doses from Courtney's Research Medical Tower Pharmacy.

The case against Courtney stripped him of his pharmacy licenses and forced him to sell two pharmacies -- in Kansas City and in suburban Merriam, Kan.

Under the plea agreement, Courtney's estimated assets of more than $10 million are to be used as restitution for victims in the criminal case, Porter said.

Courtney also faces about 300 lawsuits filed in state court claiming fraud and wrongful death. Some of those lawsuits also name two pharmaceutical companies -- Eli Lilly & Co. and Bristol-Myers Squibb Co. --claiming they knew about the dilutions but did nothing with that knowledge.

Representatives of the two companies did not immediately return calls Tuesday.

Courtney's guilty plea makes it easier to demonstrate liability in the lawsuits, said Michael Ketchmark, an attorney for the 173 plaintiffs, who include relatives of the cancer patients.

``The drug companies were saying that we couldn't prove the dilutions, but that domino has fallen,'' Ketchmark said Tuesday.

Ketchmark said the issue was not financial but making the drug companies responsible for the way pharmacists use their products.

In a handwritten note released by prosecutors, Courtney said he began diluting medications to raise money to pay more than $600,000 in taxes and for $330,000 on a pledge to his church.