It is possible to make the request. You may have to show that you have trimmed everything else out of your budget besides absolute necessities in order to justify a deviation from the child support schedules. Otherwise, while the Court is sympathetic to the cost of treating your medical condition, the Court also strongly believes that your children deserve to be supported.
You can reach Harkess & Salter LLC at (303) 531-5380 or info@Harkess-Salter.com. Stephen Harkess is an attorney licensed in the state and federal courts of Colorado. This answer is for general information only and does not create an attorney client relationship between Stephen Harkess or Harkess & Salter LLC and any person. You should schedule a consultation with an attorney to discuss the specifics of your legal issues.
The Court and the State have a vested interest in making sure that children have financial support from both parents. As Mr. Harnkess said, you would be asking for a deviation from the calculated support. Deviations have to be in a child's best interests. I would suggest that you speak with an attorney, as much will depend on the amount of the deviation and factual circumstances regarding your child's needs.