Antiviral drugs call the medicines suppressing activity of the microbes and viruses which got to an organism and caused various diseases. Antiviral drugs use also for treatment of diseases, and in the preventive purposes.
The antiviral drugs having clinically proved efficiency exists much less, than antibiotics. Proceeding from features of primary use, antiviral drugs can be divided into several groups: the antiherpetic, antiretroviral, anticytomegaloviral, anti-influenza and possessing an expanded range activities.
||Rimantadinum, Amantadin, Oseltamivir (Ozeltamivir), Arbidol, Zanamivir
||Acyclovir, Valatsiklovir, Pentsiklovir, Famtsiklovir, Idoksuridin, Riodoxolum, Famtsiklovir, Gantsiklovir, Bonafton, Alpizarin, Glycyrrhizic acid, Florenalum, Atazanavir, Tebrophenum, Tromantadin
||Didanozin, Nelfinavir, Stavudin, Zidovudin, Indinavira sulfate, Ritonavir, Amprenavir, Sakvinavir, Abakavir, Zaltsitabin, Efavirenz, Lamivudin, Fosfazid, Indovir
|Antiviral drugs with an expanded range of activity
||Ribavirin, Lamivudin, Interferona, Yodantipirin, Oksolin, Flakozid, Tiloron
Depending on a disease and properties various antiviral means apply inside, parenterally or locally (in the form of ointments, creams, drops).
M2 channels blockers
Drugs of this group, blocking ionic influenza virus M2 channels, break its ability to get into cells and to release a ribonucleoprotein. Thus the most important stage of replication of viruses is oppressed. Amantadin and Rimantadinum affect only an influenza virus And.
Amantadin — the first anti-influenza drug with the proved clinical performance. Now as antiviral means in Russia is not appointed. Due to presence of dofaminer-gichesky activity amantadin apply in Parkinson's disease.
Rimantadinum — domestic drug, a close analog of an amantadin. It is well soaked up from a GIT. High concentrations are created in fabrics and also nasal cavity slime, saliva, plaintive liquid. Indications — treatment and prevention of the flu caused by virus A. Treatment by Rimantadinum should be begun not later than in 18 — 24 h after emergence of the first simptomoz diseases. Preventively it is accepted (efficiency of 70 — 90%) if anti-influenza vaccination was not carried out or from the moment of its carrying out there passed less than 2 weeks. Drug is usually well transferred, sometimes causes a headache, dizziness, irritability, disturbance of concentration of attention.
Neuraminidase – the enzyme which is a part of a cover of some viruses, including an influenza virus. The neuraminidase helps virus particles to be released from the infected cell and accelerates penetration of a virus into other cells of airways, providing spread of an infection.
Inhibitors are the substances which are slowing down or preventing a course of any chemical change. Inhibitors suppress activity of neuraminidases of influenza viruses that limits penetration of a virus into a cell and an exit of a new virus particle from a cell upon termination of a reproduction cycle. Thus defeat is prevented by a virus of new cells. Inhibitors of a neuraminidase are effective against all types of an influenza virus, including their various strains. Today the most known inhibitors of a neuraminidase are Ozeltamivir and Zanamivir.
It should be noted that use for treatment and prevention of flu of many other antiviral drugs, such as Dibazolum, oxolinic ointment, tebrophenum, Florenalum, interferon in the form of nasal drops, has no sufficient reasons in terms of evidential medicine as their efficiency is not studied in randomized clinical trials.
The main drugs of this group having clinically proved efficiency: Acyclovir, Pentsiklovir, Famtsiklovir, Valatsiklovir. These medicines have similar structure and the mechanism of action. They suppress synthesis of DNA at those viruses of herpes which go through a replication stage, but do not influence those viruses which are in the "sleeping" inactive state.
It is not proved yet that use during pregnancy of antiherpetic drugs is harmless. With carefully verified dosage, pregnant women can accept Acyclovir, but only after consultation with the personal doctor.
When feeding, drug gets into breast milk so its use in this case too is undesirable. Dosages of drugs for children are calculated individually according to the special scheme. There are data that prescribing of some antiviral drugs of this group is contraindicated to HIV-positive children. The combined effect of antiherpetic drugs with some other can lead to disturbance of functions of kidneys, to neurotoxic reactions.
Antiretroviral drugs are used for therapy and prevention of HIV infection. There are 3 classes ARVP:
1. Nukleozidny inhibitors of the HIV reverse transcriptase.
2. Nenukleozidny inhibitors of the HIV reverse transcriptase.
3. HIV protease inhibitors.
Simplicity of the device of the HIV virus strongly complicates fight against it. Such means as boiling or processing by strong acid which easily kill a virus are not suitable for treatment of people. Safer means - antibiotics which well cope with bacteria cannot help with a case with a virus as do not affect it.
The drugs operating on HIV are called antiretroviral drugs. They influence a virus, blocking effect of any given its enzymes and by that without allowing a virus to breed in lymphocytes. Action different antiretrovirusnymkh drugs is directed to various stages of a life cycle of HIV. Unfortunately, practically all antiretroviral drugs are strongly toxic, and is much bigger, than antibiotics.
Other antiviral drugs
Iodantipyrine is called compound of iodine and antipyrine. This drug is synthesized more than 120 years ago, but in medicine it began to be applied actively about 60 years ago. Drug has interferogenny, immunomodulatory, anti-inflammatory properties. Most often it is applied to treatment of tick-borne encephalitis. Collateral impacts on an organism are nausea, hypostases, an allergy.
Oxolinum is the popular antiviral drug used outwardly. Besides, the efficiency of this drug is unproven. Acidum oxolinicum and Oxolinum are substances, different in pharmacological properties.
Flakozid is the antiviral vegetable matter received from plants of family rutic. It is applied in treatment of hepatitis, herpes, measles, depriving. On the structure it is close to flavonoids.
Interferonami is called by a big range of the proteins having similar properties which the organism marks out as the response to invasion of a foreign microorganism – a virus. These are protective substances thanks to which cells become insensitive in relation to viruses. Interferona are subdivided into several groups. Unfortunately, interferona often give side effects, both from heart, and from a stomach and intestines.
K-tiosemikarbazon which virulotsidny action was described by G. Domagk (1946) was the first drug offered as specific antiviral means.
Drug of this group thioacetazone has some antiviral activity, but is insufficiently effective; it is used as antituberculous remedy.
Derivative this group 1.4-quinone-guanyl-gidrazinotio-semicarbazone under the name Faringoseptum (Faringosept, Romania) is applied in the form of "perlingvalny" (rassasyvayemy in an oral cavity) tablets to treatment of infectious diseases of upper airways (tonsillitis, an ulitis, stomatitis, etc.).
Further it was synthesized Kmetisazon, effectively suppressing a reproduction of viruses of smallpox, and in 1959 - K nucleoside idoksuridin, by the appeared effective anti-virus remedy suppressing a virus of a herpes simplex and a vaktsiniya (vaccinal disease). Side effects at system use limited a possibility of wide use of an idoksuridin, but it remained as an effective remedy for topical administration in ophthalmologic practice in a herpetic keratitis. After idoksuridiny began to receive other nucleosides among which highly effective antiviral drugs, including Katsiklovir, Kribamidil (Kribavirin), etc. were revealed.
In 1964 the remantadin and other derivatives of an adamantan which appeared effective antiviral remedies was synthesized Kamantadin (see Midantanum), then.
Outstanding event was discovery of endogenous K interferon and establishment of its antiviral activity. The modern technology of a recombination of DNA (genetic engineering) opened a possibility of wide use of interferon for treatment and prevention of viral and other diseases.
Domestic researchers developed a number of synthetic and natural (plant origin) drugs for system and topical administration in viral diseases (see Bonafton, Arbidol, Oxolinum, Deytiformin, Tebrophenum, Alpizarin, etc.).
Now it is established that action of a number of the immunostimulating and antiviral means (see Prodigiosanum, Poludanum, Arbidol, etc.) is connected with their interferonogenny activity, i.e. ability to stimulate formation of endogenous interferon.