Gaddafi went on a hunger strike last month in protest at his incarceration without trial since 2015.
Citing unidentified sources, Al Hadath said he had suffered a sharp drop in his blood sugar level.
Gaddafi has been charged in Lebanon with concealing information about the fate of Imam Musa al-Sadr, a Lebanese Shi’ite Muslim cleric who disappeared while on a trip to Libya in 1978.
Muammar Gaddafi was captured and killed by rebels in 2011.
(Reporting by Hatem Maher; Writing by Muhammad Al Gebaly; Editing by Andrew Cawthorne and Kevin Liffey.)