Levothyroxine (Synthroid, Levoxyl) is a thyroid hormone replacement that requires precise, consistent absorption. Teaching: (1) take orally on an empty stomach 30 to 60 minutes before breakfast (or 4 hours after the evening meal at bedtime) with a full glass of water at the same time daily, (2) separate from calcium, iron, magnesium, antacids, sucralfate, and bile-acid binders by at least 4 hours because they impair absorption, (3) coffee within 1 hour reduces absorption — wait at least 1 hour, (4) hypothyroidism is usually lifelong; the medication is not stopped when symptoms improve, (5) bioavailability differs between brand and generic — keep the same product to maintain stable TSH; if the brand or generic must change, recheck TSH in 6 weeks, (6) report palpitations, tremor, heat intolerance, weight loss, or insomnia (over-replacement) and persistent fatigue, cold intolerance, weight gain, or constipation (under-replacement). Pregnancy requires a 25 to 30 percent dose increase.
In-depth explanation
Choice 2 captures the four core absorption rules: empty stomach, full water, fixed time, and consistency. Calcium and iron pair-binding is the most commonly tested interaction.
For study reference only. Always follow current clinical guidelines and your institution’s protocols.