Final answer:
For a 55-year-old with DM, HTN, and chronic renal failure with creatinine 2.4, ACE inhibitors or ARBs are usually recommended due to their renal-protective effect, but renal function should be closely monitored. Loop diuretics may increase creatinine levels and should be used with caution.
Step-by-step explanation:
For a 55-year-old patient with newly diagnosed diabetes mellitus (DM) and hypertension (HTN) who also has chronic renal failure with a creatinine level of 2.4, careful selection of medication is crucial to avoid further renal damage. Considering the patient's condition, angiotensin-converting enzyme inhibitors (ACE inhibitors) or angiotensin receptor blockers (ARBs) are usually recommended as they have a renal-protective effect in addition to controlling blood pressure. ACE inhibitors work by blocking the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor that can further exacerbate renal impairment. However, it is essential to monitor renal function regularly, as these agents can potentially affect renal perfusion pressure and function, especially in cases of significant renal impairment or if the patient is on other medications that can affect renal blood flow. Diuretics may be used for hypertension, but those working on the loop of Henle (Loop diuretics) can increase creatinine levels, hence should be used with caution. Thiazide diuretics are generally avoided in advanced renal failure due to lack of efficacy. Moreover, non-pharmacological interventions should also be emphasized as part of the comprehensive management plan for this patient.