Clinical Pharmacology Chapter 34 Gastrointestinal Drugs Q&A (1 OF 56) Sample Questions
1. MP is a 50-year old woman with hypothyroidism taking Levothyroxine 50 mcg daily. She has been recently diagnosed with mild heartburn. Pharmacist recommends Aluminum hydroxide antacids. What should the pharmacist instruct to the patient?
- A. Separate antacids 2 hours from Levothyroxine.
- B. Take antacids 30 minutes before Levothyroxine or 2 hours after Levothyroxine
- C. Take Levothyroxine in the morning and antacids at noon.
- D. Take Levothyroxine and antacids in the morning with a full glass of water.
- E. Take both Levothyroxine and antacids anytime time of the day with a glass of warm milk.
Tips: Ref. CTC: Al, Mg, Ca, Fe, Sucralfate, orlistat, cholestyramine, Polystyrene sulfate. Separate atleast for 4 hours.
Aluminum Hydroxide may decrease the serum concentration of Levothyroxine by preventing absorption of T4 from the gastrointestinal tract. Consider therapy modification by separating administration of Oral levothyroxine and aluminum hydroxide by at least 4 hours.
Concurrent use may reduce the efficacy of levothyroxine by binding and delaying or preventing absorption, potentially resulting in hypothyroidism. Calcium carbonate may form an insoluble chelate with levothyroxine, and ferrous sulfate likely forms a ferric-thyroxine complex. Administer levothyroxine at least four (4) hours apart from these agents. Patients treated concomitantly with orlistat and levothyroxine should be monitored for changes in thyroid function.