Brief introduction of swine flu drugs
Brief introduction of swine flu drugs
Text/Pharmacy Department Liu Bodeng
According to the World Health Organization (WHO), there have been recent outbreaks of human swine flu (A/H 1N 1) in the United States and Mexico. As of April 23rd, these two countries reported 898 influenza-like cases and 62 deaths (case fatality rate: 6.9%). People infected with swine flu virus will have flu-like symptoms. The incubation period of the virus is one week, and there is no specific vaccine at present (27th). The Mexican government announced on the 24th that it would launch a large-scale vaccination program, but later confirmed that the planned common influenza vaccine was ineffective against the new swine flu virus. Tamiflu (oseltamivir) is effective in the early stage of virus infection, but it is resistant to amantadine and rimantadine. This drug has been widely used in the prevention and treatment of avian influenza before, and it also has a certain effect on this new swine flu virus. This paper briefly introduces the pharmaceutical aspects of Tamiflu (oseltamivir phosphate).
Oseltamivir phosphate, trade name Tamiflu, alias Tamiflu and Kefu, each capsule contains 98.5 mg of oseltamivir phosphate (equivalent to 75 mg of oseltamivir). Produced by Swiss Roche Pharmaceutical Company, 1999 was listed in the United States and in China in the second half of 2002. The market price is about 30 yuan per grain. Tamiflu can inhibit the spread of virus in human body including respiratory system by inhibiting the activity of neuraminidase, thus breaking the cycle of virus infection. When neuraminidase is inhibited, viruses can't get out of the cells that shelter them, and then die, and they can't spread and infect other cells in the human body. Neuraminidase exists in both influenza A and B viruses, so oseltamivir is effective for both influenza A and B virus infections. These two drugs have greatly reduced the virus spread by sneezing, but they can't stop completely.
Drug supply: Tamiflu is not available in our hospital at present. Gilead, the original research and development company of Tamiflu, has obtained at least two patents related to oseltamivir in China, one of which will expire on February 26th, 20 16, and the other will expire on August 22nd, 20 17. In 2005, Roche authorized two pharmaceutical companies to produce and sell Tamiflu generic drugs in China, and the Tamiflu they produced was only used to prevent and control influenza epidemics. "Leganqing" is a drug injected into the nasal cavity, and its application scope is smaller than Tamiflu. According to relevant data, the product can still be used in the case of Tamiflu resistance, so it is also a better choice. According to the Patent Law of People's Republic of China (PRC) revised for the second time in 2000. Article 49 stipulates: "In case of national emergency or extraordinary circumstances, or for the purpose of public interest, the patent administration department of the State Council may grant a compulsory license to exploit the invention patent or utility model patent." Therefore, once swine flu is prevalent in China, the government can authorize large-scale production of the drug without worrying about the supply situation.
Drug resistance: There are very few viruses resistant to oseltamivir, but influenza virus has mutated in human infected people, and the mutated virus has obvious drug resistance to Tamiflu, which leads to a linear decline in drug efficacy. The report said that during the treatment of two patients infected with avian influenza virus in Vietnam, experts found that the influenza virus in the two patients had mutated, and they had a very obvious drug resistance to Tamiflu and died. Roche issued a statement saying that in the case of drug resistance, in addition to increasing the dose of Tamiflu, other antiviral drugs may be needed to deal with the influenza virus. However, Tamiflu is not perfect in inhibiting neuraminidase, because neuraminidase can still survive and fight Tamiflu. And "for any drug, viruses can evolve against it. You can't just use one drug to deal with it. " The structure of "Legongqing" is different from that of "Tamiflu", and the virus is less likely to develop drug resistance to it. "Leganqing" may still be effective against viruses that produce Tamiflu resistance. However, the drug has not been marketed in China.
Adverse reactions: The main serious adverse reaction is insanity, also called hallucinogenic effect. From 1999 to 2005, only 1 2 6 cases related to adverse reactions such as insanity were recorded in the world, mainly in Japan. The US Food and Drug Administration (FDA) warned that Tamiflu, a famous anti-influenza drug known as the "Avian Influenza nemesis", may cause serious side effects such as insanity and hallucination in patients, especially children, and even lead to death.
Efficacy: It can reduce the severity of symptoms by 40%. Oral administration of the drug within 2-4 hours of the first symptom can shorten the course of disease by 40%, and early use of oseltamivir will maximize its curative effect. Taking oseltamivir within/0/2 hours after symptoms appear can shorten the course of disease by 3. 1 day compared with taking it 48 hours after symptoms appear. It can quickly relieve influenza high fever, and the use of oseltamivir does not inhibit the immune response of the body to influenza virus infection.
Usage: Therapeutic oseltamivir: 75 mg for adults, twice a day for 5 days, starting to take medicine within 2 days after symptoms appear. Children with body weight 15 kg use 30 mg, 15 ~ 23 kg use 45 mg, 24 ~ 40 kg use 60 mg, and over 40 kg use 75 mg. 65438+ is not recommended for children under 0 years old. Creatinine clearance rate
Extra topic: Illicium verum is produced in China and Viet Nam, and contains an important medicinal ingredient-shikimic acid. Shikimic acid is an important raw material for the effective preparation of Tamiflu, but it is not feasible to take Illicium verum directly to prevent and treat influenza. So don't believe that star anise can treat swine flu, and don't store it personally.