1. Viral spectrum and epidemiology of common respiratory infections
2. Antiviral strategies for common respiratory viral infections
1. Indications for medication
Recommendation 1: Routine administration of antiviral drugs is not recommended for respiratory viral infections in non-high-risk populations
- Acute respiratory infections are generally self-limited, such as patients who do not have upper respiratory tract infection and the suspected pathogen is considered to be rhinovirus, etc., and mild patients are mainly treated with symptomatic relief and supportive treatment, and antiviral drugs can not be given.
Recommendation 2: Empiric antiviral therapy should be given to patients with severe symptoms, prolonged disease, severe lower respiratory tract infection, or high-risk populations, depending on the most likely causative virus or POCT results, but high-quality evidence is lacking.
- For syncytial virus infection, which is common in high-risk populations, early treatment with ribavirin antiviral drugs is recommended
2. Timing of medication
Suggestion: Antiviral drugs are generally given within 48 hours of onset or after the first visit, and the duration of drug use is generally determined according to the course of the drug, in principle, no more than 10 days.
- The incubation period of the virus invasion of the respiratory tract is generally 48 hours (24-96 hours), and the virus begins to reach the peak of detoxification after 24-72 hours of invasion of the respiratory tract.
- After 48 hours of onset, the duration of the disease was shortened by up to 1 day;
- The virus is generally detoxified in the human respiratory secretion for 3-7 days, and the average detoxification time is 4.5 days, for example, the influenza virus cannot be detected in the secretion after 6-10 days after influenza virus invades the respiratory tract;
- The normal human adaptive immune response can last for 5-14 days, and the production of antibodies is generally produced 1-2 weeks after viral infection, so the course of the disease after respiratory viral infection is generally within 7-10 days.
3. Selection of antiviral drugs and precautions for medication
1. Classification of drugs
2. Broad-spectrum antivirals
(1) Ribavirin
- Also called riboside, it is a nucleoside antiviral drug
- It is also called "viral azole" in China, and the in vitro test has a selective inhibitory effect on respiratory syncytial virus
- The Continental Food and Drug Administration approved ribavirin granules for viral pneumonia and bronchitis and skin herpes virus infections caused by respiratory syncytial virus (RSV).
- Antiviral efficacy is confirmed, but a combination of drugs such as oseltamivir is usually required
(2) Interferon
- The classification of interferon preparations can be divided into two categories: human natural dry antibiotic α, β and γ according to different production methods.
- Genetically engineered interferons can be divided into A, β, and Y types according to the molecular structure and antigenicity of gene expression, and more than 20 isoforms are divided into α1, α2, and α3 according to the differences in amino acid composition within the same type. Within the same isoform, it is subdivided due to the difference in amino acids, such as A2: there are three types: A2A, A2B, and A2C
- Human natural interferon is obtained by stimulating lymphoblasts and human leukocytes respectively, and then purifying and preparing them.
- The main recombinant preparations used in clinical practice include α2a, α2b and α1b.
- Interferon does not directly inactivate the virus, but rather exerts its effect by inducing the synthesis of antiviral proteins (AVPs) by cells. Interferon first acts on the interferon receptor of the cell, and through a series of life and rest processes such as signal transduction, it activates the expression of a variety of antiviral proteins in the cell gene to achieve the inhibitory effect on the virus. Antiviral proteins mainly include 2'-5'A synthetase and protein kinase. The former degrades viral mRNA, while the latter inhibits the synthesis of viral polypeptide chains, terminating viral replication.
- Characteristics of action: indirect, broad-spectrum non-specific, rapid action, species-specific
- Main adverse reactions: or when combined with ribavirin, it produces influenza-like syndrome, bone marrow suppression, mental abnormalities, induces autoimmune diseases, shortness of breath and dry cough, etc., and is prone to cause central nervous system, cardiac and systemic adverse reactions in the elderly
- It is mainly used for respiratory syncytial virus, influenza virus, herpes virus and other infections
(3) Arbdol
- Clinical Pharmacy Guidelines for Antirespiratory Viral Drugs
- In addition to being effective against influenza A and B viruses, it also has inhibitory effects on a variety of respiratory viruses, including: influenza C virus, rhinovirus, adenovirus, respiratory syncytial virus, coxsackie virus, hantavirus, B and C viral hepatitis virus, coronaviruses and other enveloped and non-enveloped viruses, RNA and DNA viruses, PH-dependent and non-dependent viruses
- The "Diagnosis and Treatment Protocol for Novel Coronavirus Pneumonia (Trial Sixth Edition, Seventh Edition)" includes Arbidol in the general treatment of adult patients with new coronavirus pneumonia
- Prohibit and use with caution
- It is forbidden for those who are allergic to Arbidol and the excipients in its preparations
- Use with caution in patients with sinus node lesions or insufficiency, and pay attention to ECG monitoring
- Liver and kidney insufficiency, children, pregnancy, and the elderly should be used with caution, and lactation should be suspended
- Adverse effects
- The main manifestations are nausea, diarrhoea, dizziness, and elevated serum aminotransferases
3. Anti-DNA viral drugs
(1) Ganciclovir
- Instructions
- Cytomegalovirus infection
- Herpes simplex virus keratitis
- Prohibit and use with caution
- It is forbidden for those who are allergic to this drug or acyclovir
- Patients with severe leukopenia, neutropenia, anemia, and thrombocytopenia should use with caution
- Use with caution in patients with severe immunodeficiency
- Adverse effects
- The main toxicity is neutropenia, dose adjustment or discontinuation if necessary
- May cause sperm loss, reproductive impairment, and contraception for at least 90 days after use in men
- Women who may become pregnant should use contraception, which can cause fetal damage
- It is irritating and should be avoided from direct skin contact
(2) Valganciclovir
(3) Foscarnet
- Selectively inhibits viral DNA polymerase without activation
- Nephrotoxicity, anemia, electrolyte imbalances, nausea and vomiting
- Considered only when ganciclovir is resistant (14 days after treatment, viremia persists, or clinical symptoms do not improve or resolve)
(4) Cidofovir
- Deoxycytilate analogues that do not require activation of viral enzymes
- In addition to anti-HCMV activity, it also has antiviral activity against other viruses such as adenovirus and herpes simplex virus. In the past, it was almost exclusively used for the treatment of HCMV infection in AIDS patients
- Nephrotoxicity, which can be partially attenuated by concomitant use of probenecid
- The half-life of the active metabolite is 65h
4. Anti-RNA viral drugs
5. New crown medication
来源:Dobutamine