Hepatitis B is a serious-to-potentially fatal viral infection of the liver. The hepatitis B virus can be spread by blood or blood products, sexual contact, or contaminated needles or instruments. Health care workers are at especially high risk for contracting hepatitis B due to needle sticks. Hepatitis B has a higher mortality than other types of hepatitis. Individuals infected may also develop a chronic condition or become a carrier. In the past, hepatitis B was treated with interferons. In 2004 and 2005, adefovir (Hepsera) and entecavir (Baraclude) were approved specifically for treating chronic hepatitis B. In 2006, another nucleoside reverse transcriptase inhibitor, telbivudine (Tyzeka) was found to be very effective in preventing viral replication in active hepatitis B patients.
All three of these antiviral drugs are indicated for the treatment of adults with chronic hepatitis B who have evidence of active viral replication and either evidence of persistent elevations in serum aminotransferases or histologically active disease. The drugs inhibit reverse transcriptase in the hepatitis B virus and cause DNA chain termination, leading to blocked viral replication and decreased viral load.
These drugs are rapidly absorbed from the GI tract, with peak effects occurring in 0.5 to 1.5 hours (entecavir), 0.5 to 4 hours (adefovir), and 1 to 4 hours (telbivudine). Entecavir and adefovir are metabolized in the liver and excreted in the urine. Telbivudine is excreted unchanged in the urine. Adefovir has a half-life of 7.5 hours; entecavir has a half-life of 128 to 149 hours; and telbivudine has a half-life of 40 to 49 hours. It is not known whether any of these drugs crosses the placenta or enters breast milk.
These drugs are contraindicated with any known allergy to the drugs and with lactation because of potential toxicity to the infant. Use caution when administering these drugs to patients with renal impairment and severe liver disease and those who are pregnant.
mortality – n. 死亡率
interferon – n. 干扰素
adefovir – n. 阿德福韦 Hepsera – n. 贺维力
entecavir – n. 恩替卡韦 Baraclude – n. 博路定
telbivudine – n. 替比夫定 Tyzeka – n. 替泽卡
serum aminotransferases – 血清转氨酶
aminotransferase – n. 转氨酶
viral load – 病毒裁量
telbivudine – n. 替比夫定
Test 1. Nathaniel has severe pruritus due to having hepatitis B. What is the best intervention for his comfort?
A. Give tepid baths.
B. Avoid lotions and creams.
C. Use hot water to increase vasodilation.
D. Use cold water to decrease the itching.
2. You’re discharging Nathaniel with hepatitis B. Which statement suggests understanding by the patient?
A. “Now I can never get hepatitis again.”
B. “I can safely give blood after 3 months.”
C. “I’ll never have a problem with my liver again, even if I drink alcohol.”
D. “My family knows that if I get tired and start vomiting, I may be getting sick again.”
For pruritus, care should include tepid sponge baths and use of emollient creams and lotions.
2. D. “My family knows that if I get tired and start vomiting, I may be getting sick again.”
Hepatitis B can recur. Patients who have had hepatitis are permanently barred from donating blood. Alcohol is metabolized by the liver and should be avoided by those who have or had hepatitis B.
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