Interferons 干扰素类
Interferons are substances naturally produced and released by human cells that have been invaded by viruses. They may also be released from cells in response to other stimuli, such as cytotoxic T cell activity. A number of interferons are available for use. Several are produced by recombinant DNA technology, including interferon alfa-2b (Intron-A), interferon alfacon-1 (Infergen), peginterferon alfa-2a (Pegasys), peginterferon alfa-2b (Peg-Intron), and interferon beta-1b (Betaseron). Interferon alfa-n3 (Alferon N) is produced by harvesting human leukocytes. Interferon beta-1a (Avonex) is produced from Chinese hamster ovary cells. Interferon gamma-1b (Actimmune) is produced by Escherichia coli bacteria. The interferon of choice depends on the condition being treated.
Therapeutic Actions and Indications
治疗作用和适应症
Interferons act to prevent virus particles from replicating inside cells. They also stimulate interferon-receptor sites on noninvaded cells to produce antiviral proteins, which prevent viruses from entering the cell. In addition, interferons have been found to inhibit tumor growth and replication, to stimulate cytotoxic T-cell activity, and to enhance the inflammatory response. Of interest, interferon gamma-1b also acts like an interleukin, stimulating phagocytes to be more aggressive.
Pharmacokinetics
药代动力学
The interferons are generally well absorbed after subcutaneous or intramuscular injection. They have a rapid onset of action and peak within 3 to 8 hours, with a half-life ranging from 3 to 8 hours, with the exception of interferon beta-1a, which has an onset of action of 12 hours and a reaches peak levels in 48 hours, with a half-life of 10 hours. They are broken down in the liver and kidneys and seem to be excreted primarily through the kidneys.
Contraindications and Cautions
禁忌症和注意事项
The use of interferons is contraindicated in the presence of known allergy to any interferon or product components. Many of the interferons are teratogenic in animals and therefore should not be used during pregnancy. Use of barrier contraceptives is advised for women of childbearing age. It is not known whether these drugs cross into breast milk, but because of the potential adverse effects on the baby, it is advised that the drugs not be used during lactation unless the benefits to the mother clearly outweigh any risks to the baby. Caution should be used in the presence of known cardiac disease because hypertension and arrhythmias have been reported with the use of these drugs; with myelosuppression because these drugs may further suppress the bone marrow; and with central nervous system (CNS) dysfunction of any kind because of the potential for CNS depression and personality changes that have been reported.
Adverse Effects
不良效应
The adverse effects associated with the use of interferons are related to the immune or inflammatory reaction that is being stimulated (stimulating the immune and inflammatory response causes a flu-like syndrome with lethargy, myalgia, arthralgia, anorexia, nausea). Other commonly seen adverse effects include headache, dizziness, bone marrow depression, depression and suicidal ideation, photosensitivity, and liver impairment.
interferon – n. 干扰素
recombinant – n. 重组体
Intron-A – n. 甘乐能
interferon alfacon-1 – n. 干扰素α-1
Infergen – n. 千复津
peginterferon alfa-2a – n. 培干扰素α-2a
Pegasys – n. 派罗欣
Peg-Intron – n. 佩乐能
interferon beta-1b – n. 干扰素β-1b
Betaseron – n. 倍泰龙
interferon alfa-n3 – n. 干扰素α-n3
Alferon N – n. 干扰素α-n3商品名
Avonex – n. 阿沃纳斯
hamster – n. 仓鼠
Actimmune – n. 阿克姆
teratogenic – a. 产生畸形的
barrier contraceptives – 屏障避孕器
1. A 27-year-old man with HIV disease and hepatitis B is hospitalized for treatment of his hepatitis B. He has begun on intravenous treatment with interferon. After administration, he develops fever, chills, and myalgias. Physical examination reveals that the lungs are clear to auscultation bilaterally. What is the most likely explanation for this reaction?
A. Expected adverse event
B. Drug toxicity
C. Underlying atypical pneumonia
D. Underlying bacterial pneumonia
2. A 46-year-old man with HIV disease presents to clinic because of a change in the appearance of his face over the past couple of months since he started antiviral therapy. His face looks sunken, particularly in the cheeks. His arms also appear to be wasting, whereas his breast tissue seems larger. He is unsure why this occurred. What medication is most likely responsible for this patients’ appearance?
A. Efavirenz
B. Enfuvirtide
C. Ritonavir
D. Nevirapine
1. A: Expected adverse event.
Adverse effects include flulike symptoms on injection, such as fever, chills, myalgias, arthralgias, and GI disturbances. Fatigue and mental depression are common. These symptoms subside with subsequent administrations. The principal dose-limiting toxicities are bone marrow suppression including granulocytopenia, neurotoxicity characterized by somnolence, and behavioral disturbances. 2. C: Ritonavir.
The patient is suffering from lipodystrophy, which is most commonly associated with protease inhibitors used for HIV therapy. Ritonavir is a protease inhibitor. Protease inhibitors are thought to inhibit lipid metabolism leading to lipodystrophy. Lipodystrophy has been associated with nucleoside reverse transcriptase inhibitors; however, it is more common with protease inhibitors.
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