USMLE combined Step 1/3 question. Step 3-what medication do you start? Step one – what are the classes/mechanism of actions of these medicines?

Question

Let’s say the patient in the previous question has progressed. He is now had mild encephalopathy but this has been controlled with lactulose and his ascites has been controlled with diet and his diuretics. He developed hematemesis and presented to the ER.

exam: HR 120, BP 60/palpable, obtunded, icteric, splenomegaly, no ascites

Labs: hemoglobin 9.2, platelets 70, INR 1.5, total bilirubin 2.2, sodium 130, bone 90, creatinine 1.3.

Intubated. Central line placed. Fluid resuscitated.EGD shows large varices no active bleeding but brought in the stomach. What medicines do you start?- step 3/mechanism of action? Step 1

Answer 1

WHAT MEDICINES DO YOU START? Non-bleeding varices treated with beta-blockers. Beta-blockers can be used to prevent variceal hemorrhage by lowering the blood pressure provided that there is no contraindication. Resuscitate the patient with fluids and blood products (fresh-frozen plasma and vitamin K to treat coagulopathy, if present.) Cirrhotic patients who have upper gastrointestinal bleeding frequently have a coexisting bacterial infection or develop one after admission, so prophylactic antibiotics preferably prior to endoscopy is recommended for these patients. When the patient is stable, he should be given counseling, including alcohol cessation.

BETA BLOCKERS: nonselective β-blockers relieve portal hypertension.

CEFTRIAXONE: The mechanism of action of cephalosporins is analogous to that of the penicillins: (1) binding to specific penicillin-binding proteins, (2) inhibition of cell wall synthesis, and (3) activation of autolytic enzymes in the cell wall .

Answer 2

In this case you begin IV octreotide and ceftriaxone immediately as he is obtunded and usually could be infected, and given his vitals could be actively bleeding. Once pressure is relatively stable you would begin nonselective beta blocker. Any bleeding would require banding later.

USMLE 1- Octreotide decreases blood flow to Portal system by constricting splanchnic arterials so reduces Intravariceal pressure. Ceftriaxone is a cephalosporin and has the same mechanism of action of penicillin. Nonselective beta blockers were created first and block stimulation of beta receptors on the heart, smooth muscle, lungs, etc. ( b2). These are preferred in esophageal varices with bleeding so Couric and other drugs may be better. The list includes propranolol, Timolol, nadolol, pindolol