AI is a 44 year old male that presents to your community pharmacy with two prescriptions for Lasix and Aldactone. Based on your conversation with him, you are able to determine that he has chronic liver disease with cirrhosis. He relays to you that he has been on lactulose, Lasix, Aldactone, and Xifaxin for over a year. However, his gastroenterologist noticed more ascites than normal at his last visit and increased the doses on his two diuretics. CH reports having about 2-3 soft stools per day, and is otherwise doing well. He would like to know when he can pick up the new prescriptions.
Lasix 80 mg: 2.5 tablets by mouth once daily.
Aldactone 100 mg: 4 tablets by mouth once daily.
Lactulose 10g/15 ml: 30 ml by mouth three times a day.
Lasix 40 mg: 2.5 tablet by mouth once daily
Aldactone 100 mg: 2.5 tablets by mouth once daily.
Xifaxan 550 mg: 1 tablet by mouth twice daily.
Based on the patient’s history, how can you help the patient manage their liver disease? (MC)
A. Contact the prescriber to discuss that the prescription exceeds the maximum dose for Aldactone for this indication.
B. Contact the prescriber to discuss increasing the patient’s lactulose dose due to inadequate bowel movement frequency.
C. Contact the prescriber to discuss that the prescription exceeds the maximum dose for Lasix for this indication.
D. Contact the prescriber to discuss increasing the Xifaxan to 550mg PO TID to prevent hypokalemia from new diuretic regimen.
E. Fill both prescriptions as is.
Chronic liver disease is a progressive disease, which results in impaired liver function. The liver serves to synthesize albumin and clotting factors, metabolize drugs and bilirubin, and eliminate toxins and drugs. Cirrhosis, which is characterized by irreversible scarring of the liver due to fibrosis, is a sign of end stage liver disease. There are numerous complications of liver disease with cirrhosis, such as ascites, jaundice, hepatic encephalopathy, hepatorenal syndrome, and varices. While a liver transplant is the only cure for end stage liver disease, there are medications to help treat and prevent some of these complications.
Brands/Generics covered: Lasix (furosemide), Aldactone (spironolactone), Xifaxan (rifaximin)
Answer choice A is incorrect: The maximum daily dose for Aldactone for ascites due to cirrhosis is 400 mg. Portal vein hypertension is a complication of liver disease as a result of scarring and fibrosis in the liver causing resistance to blood flow from the portal vein to the liver. This resistance leads to decrease in systemic blood volume and a compensatory increase in aldosterone production to reabsorb sodium and water. As a mineralocorticoid receptor antagonist (MRA), Aldactone directly opposes this mechanism to help treat and prevent the ascites that result from excess water reabsorption while preserving potassium.
Answer choice B is incorrect: Lactulose dose is titrated to achieve 2-3 soft stools per day. Lactulose works as an osmotic laxative by pulling water into the colon to soften stool. Additionally, the body requires bacteria in the gut to break down lactulose. The gut bacteria’s degradation of lactulose results in an acidic pH leading to the conversion of ammonia to ammonium, which prevents the absorption of ammonia into the blood. Lactulose also promotes diffusion of ammonia from the blood to the colon where further conversion to ammonium takes place. The reduction in the amount of ammonia in the blood helps treat and prevent recurrences of hepatic encephalopathy.
Answer choice C is correct: The maximum daily dose for Lasix for ascites due to cirrhosis is 160 mg. While Aldactone helps oppose the secondary hyperaldosteronism that results from cirrhotic liver disease, loop diuretics are used in combination with a MRA to enhance sodium and water excretion. It is important to note that a ratio of 100 mg of Aldactone to 40 mg of Lasix is used together to help patients remain normokalemic while providing diuresis.
Answer choice D is incorrect: Xifaxan is a rifamycin antibiotic used to prevent the growth of gut bacteria that produce toxins. It is used in combination with lactulose when lactulose as monotherapy does not achieve the target stool frequency of 2-3 soft bowel movements per day. Furthermore, it is dosed as 550 mg twice daily or 400 mg three times daily.
Answer choice E is incorrect: Filling the Lasix prescription as it is currently written would result in the patient taking more than maximum dose for his indication. Additionally, it could put him at risk of becoming hypokalemic due to the ratio between the Aldactone and Lasix dose being 100:50 versus the recommended 100:40.
NAPLEX Competencies Covered:
Area 1 (Obtain, Interpret, or Assess Data, Medical, or Patient Information): 1.2 From patients: treatment adherence, or medication-taking behavior; chief complaint, medication history, medical history, family history, social history, lifestyle habits, socioeconomic background, 1.4 From medical records: treatment adherence, or medication-taking behavior; chief complaint, medication history, medical history, family history, social history, lifestyle habits, socioeconomic background, 1.5 Signs or symptoms of medical conditions, healthy physiology, etiology of diseases, or pathophysiology
Area 2 (Identify Drug Characteristics): 2.1 Pharmacology, mechanism of action, or therapeutic class
Area 3 (Develop or Manage Treatment Plans): 3.2 Therapeutic goals or outcomes and clinical endpoints, 3.4 Drug dosing or dosing adjustments; duration of therapy
Area 4 (Perform Calculations): 4.2 Quantities of drugs to be dispensed or administered.
A special thank you to all of the students I was able to meet in person as our RxExamCoach team wrapped up our live reviews across the country. You inspire me greatly to keep providing quality questions of the week! Keep studying as your licensed pharmacist goals are soon to be realized!