Why is Oseltamivir prescribed? Instructions for use, analogues, indications and contraindications of this medication will be described a little further. We will also tell you about in what form the medication mentioned can be purchased, what properties it has, whether it has side effects, etc.
Form, composition, description of the drug
On sale, this drug comes in the form of white-yellow capsules. Oseltamivir is a prodrug. When taken orally, it undergoes hydrolysis and is converted into the active substance - oseltamivir carboxylate.
In addition to capsules, this medication is also available in the form of a light powder for the preparation of an oral suspension.
Features of the medication
How does the drug "Oseltamivir"? Instructions for use states that the therapeutic effect of this medication is based on the suppression of the activity of enzymes that are located on the surface of the flu virus virion.
After the medication enters the human body, its main component is transformed into an active metabolite. Thus, oseltamivir carboxylate selectively inhibits neurominidase. As a result of such exposure, the process of reproduction of viral cells stops.
According to experts, this medication should be administered within 35 hours after the first signs of flu appear. Only in this way can the disease duration be reduced by 30%, and the likelihood of complications and the severity of symptoms - by 40%.
Pharmacokinetics of the drug
Is the Oseltamivir drug absorbed? Instructions for use indicate that about 90% of oseltamivir phosphate is absorbed in the gastrointestinal tract. The active substance is converted to oseltamivir carboxylate, and then into the systemic circulation.
About 3% of the active component binds to plasma proteins. Its bioavailability is approximately 76-85%, and the half-life is 120 minutes.
From the human body, oseltamivir carboxylate is excreted through the kidneys (about 80%) and the intestines (20%). The half-life of this drug is 6-10 hours.
Indications for use
Why is Oseltamivir prescribed (pharmaceutical group - antiviral drugs)? According to the attached instructions, this medication is used to treat influenza A and B. It is also often used to prevent these viral diseases.
Contraindications
Does Oseltamivir have contraindications (the description of the drug was presented above)? According to the instructions, this medication should not be taken with:
- hypersensitivity to the active component;
- renal failure (safety and efficacy of the drug in this category of patients have not been determined);
- in children under the age of 1 year (there is uncertainty regarding the formation of the BBB in children);
- pregnancy and breastfeeding (it is not known whether the drug is excreted in breast milk of women, and whether it affects the fetus).
It should also be noted that this medication is not recommended for children under 13 years of age, since the safety and efficacy of Oseltamivir for the prevention and treatment of influenza have not been determined by specialists.
The drug "Oseltamivir": instructions for use
Vidal (medication guide) contains complete information about how and in what dosages it is necessary to take the drug in question. However, it should be noted that only the attending physician should prescribe this medication. After all, only an experienced specialist will be able to choose the right treatment regimen that will quickly and effectively eliminate all the unpleasant symptoms of a viral disease.
So at what dosage is Oseltamivir prescribed? Instructions for use indicate that this drug should be used no later than 2 days after the onset of the first signs of influenza.
For children over 13 years old and adults, the medication is prescribed in the amount of 75 mg twice a day for 5 days. It should be noted immediately that an increase in the dosage of the drug (for example, up to 150 mg per day) does not lead to an increase in the therapeutic effect.
If the drug must be prescribed to children aged 1-12 years, then the dosage is selected depending on the body weight of the child.
For the prevention of influenza, adults and children over 13 years of age are prescribed 75 mg 1 once a day for 6 weeks (for example, during an epidemic).
In patients with Cl creatinine less than 30 ml per minute, a dosage adjustment is required (75 mg once a day for 5 days).
Side effects after taking the medication
What adverse reactions occur after taking the drug "Oseltamivir"? Instructions for use state that the most frequently occurring adverse reactions are nausea and vomiting. In most cases, such effects are mild or moderate and usually occur in the first days of treatment.
It should also be noted that some patients develop bronchitis, vertigo, insomnia, unstable angina, pseudomembranous colitis, anemia, pneumonia, a fracture of the humerus, peritonsillar abscess, and fever while taking the drug in question.
Very rarely, people taking Oseltamivir have abdominal pain, hearing loss, nosebleeds, and conjunctivitis. In most cases, such reactions occur once and disappear on their own, despite continued therapy. Such phenomena do not require the abolition of the medication.
After prescribing an antiviral drug, undesirable effects also appear in children and adolescents. These include phenomena such as a rash, toxic epidermal necrolysis, swelling of the tongue or face, arrhythmia, confusion, convulsions, and worsening diabetes.
Drug interaction
Information obtained during pharmacokinetic and pharmacological studies suggests that the development of clinically significant drug interactions with this drug is unlikely.
The instructions attached to the medicine say that the simultaneous use of this medication with probenecid leads to a 2-fold increase in the AUC of the active metabolite. But dose adjustment is not required.
Overdose cases
What signs are observed in patients taking high doses of the drug "Oseltamivir"? Reviews and instructions say that so far there have been no such cases. However, single doses of an antiviral medication can cause vomiting or nausea.
To eliminate such symptoms, symptomatic therapy is performed.
Special recommendations for taking the medicine
What should a patient know before taking Oseltamivir? Instructions for use (in children and adults, various side effects may occur) indicates that this drug is not applicable for annual vaccination. It does not prevent the development of complications that can occur with a viral disease, as well as with a bacterial infection.
Drug Analogs
Oseltamivir is a drug that is intended for the treatment and prevention of influenza. It is an antiviral agent that belongs to neuraminidase inhibitors. This medication is widely known under the brand name "Tamiflu". He has no structural analogues. The closest, but slightly inferior in effectiveness, are the following substitute drugs: Relents, Arbidol, Flustol, Kagocel and others.
Reviews and evaluations of the effectiveness of the drug
According to test results obtained in the United States of America and Mexico, the new viruses are sensitive to neuraminidase inhibitors (Zanamivir and Oseltamivir), but they are resistant to another group - adamantanes (Rimantadine, Amantadine) .
It should also be noted that the experts have not yet established the effectiveness of this medication in the treatment of influenza in people with chronic heart and respiratory diseases.
According to doctors, this drug reduces the duration of symptoms by 1 day, but this is only if treatment was started in the first few hours after contact with the patient.
To date, there is no reliable information about whether taking this drug affects the frequency of complications of viral or infectious diseases.