Final answer:
A nurse should advise the patient to take levothyroxine at least 4 hours before orlistat to avoid interference with its absorption. Close monitoring of warfarin's effectiveness is needed but does not warrant an automatic dosage change without proper assessment. Avoiding fatty foods is advised with orlistat but is not specifically related to the concerned drug interactions.
Step-by-step explanation:
When a nurse is informed that a patient is taking orlistat [Xenical], warfarin [Coumadin], and levothyroxine [Synthroid], the nurse should be aware of the potential interactions between these medications. Orlistat can interfere with the absorption of fat-soluble vitamins and possibly other drugs due to its fat-blocking properties. Since warfarin's effects can be influenced by vitamin K status (a fat-soluble vitamin), patients taking orlistat may be at risk for alterations in warfarin efficacy. Additionally, orlistat may reduce the absorption of levothyroxine, affecting thyroid hormone levels.
Therefore, the correct action would be:
- b. Give the levothyroxine at least 4 hours before giving the orlistat. This will help to ensure that the absorption of levothyroxine is not affected by orlistat.
As for warfarin, the nurse should monitor the patient's INR levels closely to see if the warfarin dose needs adjusting, but this is a decision for the healthcare provider.
Regarding diet, the patient should indeed avoid too much fatty food when taking orlistat to reduce gastrointestinal side effects and the potential for reduced efficacy of orlistat, but this is not directly related to the interactions with the medications mentioned.
Taking orlistat on an empty stomach is not necessary and is not related to the drug interactions with warfarin and levothyroxine.