What Are Antiviral Drugs?

There are many ways to resist virus infection, such as directly inhibiting or killing the virus, interfering with the adsorption of the virus, preventing the virus from penetrating into the cell, inhibiting the virus biosynthesis, inhibiting the virus release, or enhancing the host's antiviral ability. The role of antiviral drugs is mainly achieved by affecting some part of the viral replication cycle.

Chinese name: Antiviral drugs

Foreign name: antiviral agents

Introduction to antiviral drugs

Viruses are the smallest of pathogenic microorganisms. They multiply in cells. The core of the virus is ribonucleic acid (RNA) or deoxyribonucleic acid (DNA). The outer shell is a protein and does not have a cellular structure.

The virus is parasitic in the host cell and relies on the host cell's metabolic system for proliferation and replication. The virus replication process is as follows: the virus recognizes and adsorbs to the surface of the host cell; penetrates the susceptible cells through the host cell membrane; husking; synthesizes early regulatory proteins and nucleic acid polymerases; virus genome (DNA or RNA) replication; late synthesis of structural proteins; progeny virus assembly; susceptible cells release progeny virus. The above process is a replication cycle. Antiviral drugs can target any step of viral replication and exert antiviral effects. ^[1]

Most viruses lack an enzyme system and cannot live on their own. They must rely on the host's enzyme system to reproduce (replicate) themselves. Viral nucleic acids are sometimes integrated in cells and are not easy to eliminate. Therefore, antiviral drug research has developed slowly.

Diseases caused by viruses are mostly human infectious diseases. Viruses can invade different tissues and organs and infect cells to cause diseases. Common diseases caused by viruses are:

Epidemic diseases: influenza, common cold, measles, mumps, polio, infectious hepatitis, polio;

Chronic sensibility: Hepatitis B, AIDS

Latent infection: herpes keratitis, STD herpes virus.

Antiviral Drug Classification

According to the mechanism of action of antiviral drugs, current antiviral drugs can be divided into the following categories: ^[1]

1. Penetration and Hulling Inhibitors: Amantadine, Amantadine, Envevirdi, Maravero

2. DNA polymerase inhibitors: acyclovir, ganciclovir, valacyclovir, famciclovir, sodium phosphonate

3. Reverse transcriptase inhibitor:

Nucleosides: lamivudine, zidovudine, emtricitabine, tenofovir, adefovir dipivoxil

Non-nucleosides: efavirenz, nevirapine

4. Protein inhibitor: saquinavir

5.Neuraminidase inhibitors: oseltamivir, zanamivir

6. Broad-spectrum antiviral drugs: ribavirin, interferon

Amantadine

[Drug name] Rimandadine Hydrochloride

[Mechanism] Inhibits viral particles from entering the host cell, and also inhibits the early stages of viral replication, blocking the husking of viral genes and blocking the transfer of nucleic acids into the host cell. ^[2]

[Clinical application] It is clinically used to prevent and treat various infections caused by influenza A virus, and has little effect on other influenza viruses.

[Adverse reaction] After oral absorption, it can penetrate the blood-brain barrier and cause toxic side effects of the central nervous system, such as headache, insomnia, excitement, and tremor.

[Precautions] Those with liver dysfunction who are allergic to diamond drugs are prohibited.

Acyclovir

[Drug name] Aciclovir

[Mechanism of action] The mechanism of action is unique. It mainly inhibits virus-encoded thymidine kinase and DNA polymerase, which can significantly inhibit DNA synthesis in infected cells without affecting DNA replication in non-infected cells.

[Clinical application] Broad-spectrum antiviral drugs, mainly used for the treatment of herpetic keratitis, genital herpes, systemic shingles and herpes encephalitis, can also be used to treat hepatitis B ^[2] . Acyclovir is the drug of choice for treating herpes infections ^[1] .

[Adverse reactions] In addition to occasional dizziness, vomiting, and headache, itching can be seen orally. Long-term oral administration can make menstrual disorders. Leakage of blood vessels during intravenous drip can cause local inflammation. ^[1]

Precautions

For injection, it can only be instilled slowly (for 1 to 2 hours). It cannot be injected quickly, and it cannot be used for intramuscular injection and subcutaneous injection.

The effect on herpes virus encephalitis and new herpes has not been confirmed.

Adverse reactions include a temporary increase in serum creatinine, which should be used with caution in patients with renal dysfunction, pregnant women, and nursing women. Reduce renal function if appropriate.

Combined probenecid increased t1 / 2 and the area under the curve (AUC).

An appropriate amount of water must be input during the infusion to prevent the accumulation of acyclovir crystals in the renal tubules and affect renal function. The diluted solution should be used immediately, and should not be stored before use.

[Similar drugs] ganciclovir, valacyclovir, famciclovir

Antiviral interferon

[Medicine name] Interferon

[Mechanism] This product is a type of antiviral glycoprotein produced in the body after being infected by a virus or other pathogenic microorganisms, and has the activity of inhibiting virus growth, cell proliferation and immune regulation.

[Clinical application] Used for the treatment or adjuvant treatment of viral infections, such as viral keratitis, hepatitis, influenza, etc., and malignant tumors

[Adverse reactions] Stream-like syndromes such as fever, chills, headache, fatigue, etc.

[Precautions] Oral ineffective, must be administered by injection ^[1]

Zidovudine

[Drug name] Azidothymidine, zidovudine, zidovudine, AZT.

[Mechanism of action] Zidovudine's phosphorylated products can competitively inhibit the use of thymidine triphosphate by viral reverse transcriptase, thereby preventing DNA synthesis, stopping the growth of DNA strands and hindering virus reproduction.

[Clinical application] It is mainly used for the treatment of AIDS, which can reduce the incidence of HIV-infected patients and prolong their survival. Often combined with lamivudine or didanosine.

[Adverse reactions] The main toxicity is myelosuppression, manifested as anemia ^[1] .

Precautions

May have bone marrow suppression, which can cause accidental infection, delay in healing of the disease and bleeding gums. Regular blood tests are performed during medication. Instruct patients to prevent bleeding when using toothbrushes and toothpicks. Especially in the case of sore throat, fever, chills, gray skin, abnormal bleeding, abnormal fatigue and weakness, etc., the occurrence of bone marrow suppression should be noted.

Can change the sense of taste, causing swelling of the lips and tongue and oral ulcers.

Those who are deficient in folic acid and vitamin B12 are likely to cause blood changes.

Metabolized in the liver, those with insufficient liver function cause toxic reactions.

The interactions that may occur in combination with the following drugs: acetaminophen, acetylsalicylic acid, benzodiazepines, cimetidine, butepine, morphine, and sulfa drugs can all inhibit the glucuronidation of this product, and Reduce clearance and avoid combined use;

The combined application with acyclovir can cause neurotoxicity, such as lethargy and fatigue; probenecid can inhibit the glucuronidation of this product and reduce renal excretion, which may cause poisoning.

can not be combined with stavudine, the two antagonize each other ^[1] .

Ribavirin

[Medicine name] ribavirin

[Mechanism] The mechanism has not been fully elucidated. After phosphorylation in the host cell, it may play a role through a variety of ways, such as interference with guanosine triphosphate synthesis of viruses, inhibition of viral mRNA synthesis, and inhibition of some virus-dependent RNAs. Polymerase ^[1] .

[Clinical application] Broad-spectrum antiviral drugs for viral pneumonia and bronchitis caused by respiratory syncytial virus

[Adverse reactions] There is a strong teratogenic effect during use, and elimination in the body is slow. When used in large doses, it can cause heart damage. Some patients may experience diarrhea and headache when given orally or intravenously. Long-term medication can cause leukopenia and reversible anemia. ^[1]

[Precautions] Prohibited in pregnant women and women who are expecting to become pregnant ^[2] .