Final answer:
An elderly man on multiple medications for congestive heart failure must be carefully monitored due to drug interactions, his weight, and potential alterations in drug metabolism due to organ function decline.
Step-by-step explanation:
An 83-year-old man with congestive heart failure (CHF) and on multiple prescriptions, including psyllium, digoxin, phenytoin, and cimetidine, poses several medication-related considerations and concerns. With CHF, drugs like digoxin require monitoring to prevent toxicity. Phenytoin, an anticonvulsant, has interactions with digoxin and cimetidine, which also affects the metabolism of numerous drugs.
Psyllium acts as a fiber supplement, but its effects on drug absorption need to be evaluated. Furthermore, the patient's weight may alter the drug's effects; at 139 pounds, he may need dosage adjustments. In elderly patients, decreased renal and hepatic function can significantly affect drug metabolism, necessitating careful monitoring of therapeutic levels and potential side effects.