Detailed explanation of potential adverse reactions in obeticholic acid treatment

Obeticholic acid (Obeticholic acid), as a bile acid mimetic and a potent agonist of farnesoid X receptor, is widely used in adult patients with primary cholangitis (PBC) who have poor response or intolerance to ursodeoxycholic acid (UDCA) treatment. However, like many drugs, obeticholic acid may also cause a series of adverse reactions during treatment.

Among them, the most common discomforts experienced by patients include skin itching, fatigue, and abdominal pain or discomfort. In addition, some patients have reported rashes, oropharyngeal pain, dizziness, constipation, joint pain, abnormal blood lipid levels, headaches, eczema, depression, allergic reactions, and thyroid dysfunction. In a 3-year interim analysis, the presence of esophageal varices and ascites was also considered liver-related adverse events.

The incidence of skin itching appears to be dose-dependent with obeticholic acid, i.e., the higher the dose, the greater the likelihood of pruritus. This trend is particularly evident when obeticholic acid is used as a single treatment. But the good news is that if patients don't experience itching during the first three months of treatment, their risk of developing this side effect later is significantly reduced. For patients who already experience itching, doctors may recommend adding bile acid sequestrants, antihistamines, reducing the dose of the medication, or temporarily discontinuing the medication to relieve symptoms.

In addition, the use of obeticholic acid may also be associated with changes in blood lipid levels, specifically manifested as a decrease in high-density lipoprotein cholesterol and triglycerides, and an increase in low-density lipoprotein cholesterol. But a double-blind, placebo-controlled study in patients with nonalcoholic steatohepatitis (NASH) suggests that atorvastatin can be used in combination with obeticholic acid to reduce this adverse change in LDL cholesterol.

When the dose of obeticholic acid is increased to 10 to 50 mg (i.e., 5 times the recommended dose), patients may also experience a series of dose-dependent adverse reactions related to the liver, including but not limited to jaundice, worsening of ascites, portal hypertension, and attacks of primary cholangitis. A combined analysis of three placebo-controlled trials involving patients with PBC showed that at the 10 mg dose, the incidence of liver-related adverse reactions was 5.2 per 100 patient exposure years (PEY); at the 25 mg and 50 mg doses, this number rose to 19.8 and 54.5, respectively. Therefore, during obeticholic acid treatment, it is crucial to closely monitor patients' liver function and promptly detect potential liver-related adverse reactions.

In decompensated cirrhosis orCases of fatal hepatic decompensation and failure have been reported in postmarketing reports in patients with Child-Pugh Class B or C hepatic impairment when dosing frequency exceeded the recommended starting dose of 5 mg once weekly. For patients with decompensated cirrhosis or Child-Pugh class B or Child-Pugh class C PBC, it is important to follow dosing guidelines. Patients at risk for hepatic decompensation should be monitored closely while taking obeticholic acid.