Maritime security officer Perry Coppins, 61, was arrested on November 1 after a customs official thought he had taken illegal amounts of his prescription medication into the country, according to the campaign group Detained in Dubai (DiD).
The father of three from Nottingham was carrying his medicine, which is legal in the United Arab Emirates with a prescription.
Mr Coppins was jailed for five weeks despite explaining he needed enough of his medication to last him for a six-month voyage, according to DiD.
DiD said Mr Coppins’ passport had now been returned, the charges against him dropped and he was free to return home, but he was cash-strapped after spending his savings on mounting legal and living expenses as he waited to face court.
DiD chief executive Radha Stirling said: “This case should never have escalated to the point of criminal charges, but without the scrutiny of the international media it is unlikely that Perry would be a free man tonight.”