His aunt went to visit him on Tuesday
The family of Irish man Ibrahim Halawa say he was placed in solitary confinement as punishment for refusing to take glucose.
They say this is because of his ongoing hunger strike.
Mr Halawa’s aunt went to visit him on Tuesday, when he was brought to her in a wheelchair amid concerns about his health.
In a statement, the Halawa family say: "We ask our Government to urge the Egyptian government to release Ibrahim in humanitarian grounds."
They say they hold the Egyptian and Irish Government fully responsibility "if something was to happen to Ibrahim physically or mentally".
"Time is of the essence to save Ibrahim's life", the statement concludes.
Mr Halawa has said he will not end his hunger strike until he is safely released.
He was 17-years-old when he was first detained in August 2013.
His mass trial, alongside 493 other defendants, has been adjourned 19 times Cairo.
Last week, the Department of Foreign Affairs said: “This long-running and complex consular case continues to be a top priority for the Government and very significant resources continue to be devoted to the provision of support to Ibrahim Halawa and his family by the Taoiseach, by Minister Flanagan and by officials in Dublin and Cairo.
"The Irish embassy in Cairo maintains ongoing contact with the Egyptian authorities in relation to this case and seeks to ensure at all times that the Egyptian authorities fulfil their responsibility to address any issues relating to Ibrahim Halawa's health and welfare.”
The Irish embassy requested a medical check up, and this was subsequently ordered.
The department added that the Irish ambassador and his team undertake regular consular visits to Mr Halawa.