cat with mega colon

what can i do?? my cat is 13 years old and constantly constipated.  we give her lactulose and pumpkin but she still get constipated

we do not want to euthanize her!! what else can i give her to help her problem??

Has she truly been diagnosed with Megacolon, or just chronic constipation?  If chronic constipation, I suggest giving her Miralax.  Our old guy, Sven, had chronic constipation for the last few years of his life, and we gave him between 1/8 and 1/4 teaspoon of Miralax (or even the generic) mixed in about 1/2 teaspoon water) added to just a teeny bit of the gravy from canned food (so we were sure he ate it) TWICE A DAY, every day, for over 2 years.  Worked like a charm.  If his stools got a little lose, we gave him a little less each time, and if we noticed him straining, or no poops for the day, we increased the amount slightly. 

Also, once we got him transitioned from kibble to canned, I always added more water to the canned food, just to ensure he had plenty of water to help move things along. 

Just as aside, he was on Lactulose in the beginning, which did work, for awhile, then began to lose its effectiveness.  Plus it was just so sticky, it was such a pain to administer.  But you CAN administer the dissolved Miralax the same way, via syringe, if he eats only dry food.

I JUST HAD THE SAME PROBLEM WITH MY 4 YEAR OLD MAINCOON, I WAS LISTING TO THE WRONG INFO AND WAS GIVING HER FIBER, IF YOU ARE STOP AND TAKE YOUR KITTY TO THE VET,MY POOR LITTLE GIRL HAD TO HAVE BARIUM, XRAYS AND SHE IS NOW ON LACTULOSE AND CISIPRIDE TWICE A DAY IT WAS 3 TIMES A DAY, SHE IS ALSO ON A VERY LOW FIBER DIET, WHICH SHE HATES BUT I CRUMPLE A CAT COOKIE ON IT. SO GOOD LUCK

HELLO, I WAS TOLD BY MY VET FIBER WAS BINDING UP MY CAT SO SHE IS ON A VERY LOW FIBER CAT FOOD AND CISAPRIDE AND LACTULOSE, SO MY PICKY GIRL WHO I WAS TRYING TO FEED PUMPKIN TOO WAS HAPPY WHEN I TOOK IT AWAY, I WAS ALSO FEEDING HER A LOT OF KITTY COOKIES WHICH I STOPED, SO SHE IS A UNHAPPY CONSTIPATED CAT POOR CHOO!!