Each week we will aim to bring out a concise email that provides 4-5 key pieces of information addressing a specific issue in clinical therapeutics.
This week: Cholestatic Jaundice (Part 2)
Caroline Holdstock, Regional Pharmacist Manager, Ward MM
Despite the poor understanding of the reason for the itch associated with jaundice, there are many potential treatments now available. No treatment is 100% effective and the results with each one are variable.
- Biliary Drainage: is the most effective treatment so far, relieving the itch as soon as drainage is achieved, even before serum bilirubin levels are reduced. There appears to be no difference in the drainage techniques available, endoscopic, percutaneous or surgical techniques.
- Skin Care: this is often neglected and the appropriate skin care may even eliminate the need for drug therapy. Ensure that skin does not become dry, use an emollient soap substitute. Storing creams and lotions in the fridge will enhance the cooling effect. Avoid the drying effect of talcum powder, deodorants and calamine lotion. A cool cloth or ice pack may also help. Avoid heat.
- Anion Exchange Resins: cholestyramine, colestipol and colesevelam bind bile salts inhibiting their absorption in the terminal ileum. The dose of cholestyramine is 4 g given one hour before breakfast increasing to four times a day if necessary. The absorption of other medications is reduced and doses should be separated by at least 4 hours. Unfortunately, side effects are common including constipation and malabsorption, and their unpleasant taste reduces compliance. They can take up to two weeks for any improvement to occur.
- Rifampicin: the antibiotic is a rapid and strong inducer of enzymes, including CYP3A4, enhancing the metabolism of bilirubin and its breakdown products. Its antimicrobial action modifies the synthesis of secondary bile acids in the intestinal lumen. Unfortunately, it is associated with severe side effects including haemolytic anaemia, renal failure and thrombocytopenic purpura. Its effectiveness has been confirmed in clinical trials at a dose of 300 mg/day. Serious drug interactions are also common.
- Opioid antagonists: have been shown to be effective in clinical trials by preventing the binding of endogenous opioid agonists. Parenteral or oral naltrexone (0.2 microg/kg or 50 mg/day) decreased itching and reduced the perception of itch. However, in cholestatic patients a withdrawal type reaction can occur, associated with abdominal pain, anorexia and hypertension, which improves after 2-3 days. Remember that the administration of naloxone will reverse the analgesic effects of opioids used for pain.
- Serotonin Antagonists: in clinical trials sertraline (75 – 100 mg/day) has been shown to improve itch scores and was well tolerated.
- Antihistamines: are rarely effective either topically or orally.
- Ursodeoxycholic acid: has been used to treat primary biliary cirrhosis but has no effect on the associated itch.
Please consider these issues when preparing or interpreting RMMR reports or education sessions. Contributions of content or suggested topics are welcome and should be sent directly to firstname.lastname@example.org.