Whew, finally had success after a dose of magnesium citrate followed 6 hours later by fleets enema. Drastic measures, and effective. I was worried after hearing about OzMojo's ER experience! He sees the medical oncologist in the morning and will talk about what to do going forward. Thanks to all for your thoughtful suggestions.

P.s. Movicol and miralax are both polyethylene glycol based laxatives.