Levothyroxine treatment during Ramadan

INTERVENTION: In a randomized prospective design, hypothyroid patients taking levothyroxine are randomized to take levothyroxine at one of the following three times during Ramadan: (group 1) at dusk 30 minutes before Iftar meal, (group 2) 3 or more hours after Iftar meal, or (group 3) at dawn 30 minutes before Suhur meal. For groups (2) and (3), patients are instructed to allow a minimum of 3 hours between the last meal and levothyroxine and to refrain from eating and drinking for at least 30 minutes after taking levothyroxine. Levothyroxine administration instructions are provided verbally by telephone and a text message is sent to all patients midway through Ramadan as a reminder to adhere to the instructions. CONDITION: Hypothyroidism ; Nutritional, Metabolic, Endocrine ; Hypothyroidism, unspecified PRIMARY OUTCOME: Thyroid function tests (plasma TSH and free‐T4) measured on the Roche e601 immunoassay analyzer using the electrochemiluminescence immunoassay (ECLIA) sandwich principle for TSH and the ECLIA competition principle for free‐T4, within 3 months before Ramadan and repeated within 6 weeks post‐Ramadan SECONDARY OUTCOME: ; 1. The impact of age and gender on the primary outcome measure, change in thyroid function tests (see above) from pre‐to post‐Ramadan; 2. Patient compliance and satisfaction with the assigned randomized treatment assessed with a telephone call to each patient at the end of the study; INCLUSION CRITERIA: 1. Age 18 years or older 2. Hypothyroidism treated with levothyroxine for over 6 months 3. Planning to fast during the month of Ramadan 3. Ability to provide informed consent