Tamiflu

Tamiflu is an effective antiviral drug that actively fights influenza types A and B.

Indications Tamiflu

The medicine is indicated for use as a preventive or therapeutic agent for the treatment of infections caused by the influenza virus type A or B. You should start taking the medicine immediately after the first signs of the disease appear.

Tamiflu is approved for use as a treatment for infants aged six months and older in the event of a flu pandemic.

As a preventive measure, the medicine is prescribed to people who have been in contact with patients diagnosed with influenza during the period of circulation of this virus.

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Release form

The capsules are contained in blisters of 10 pieces on each plate. One package contains 1 blister.

The powder for making the suspension is available in 30 g glass bottles. One package contains 1 such bottle, which comes with a special dispenser.

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Pharmacodynamics

The active component of Tamiflu is oseltamivir, a prodrug that is metabolized in the body, turning into oseltamivir carboxylate. The metabolic products of the active component selectively and competitively suppress viral neurominidase, as a result of which viral particles fail to be released from already infected cells and penetrate healthy ones. This mechanism allows the drug to prevent the development of the disease. Oseltamivir carboxylate suppresses the process of viral replication, and in addition, reduces its pathogenic activity.

When taking the drug within the first 40 hours after the detection of signs of the disease, its duration is reduced, the risk of complications is reduced, and the severity of flu symptoms is reduced. As a preventive drug, Tamiflu reduces the risk of contracting the flu by 92% in patients who have come into contact with sick people.

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Pharmacokinetics

After oral administration, oseltamivir phosphate is rapidly absorbed through the intestine. The effect of liver esterases on the body helps to form the active form of the active substance - oseltamivir carboxylate, which is determined in plasma after half an hour. It reaches its peak concentration 2-3 hours after taking the drug. In the circulatory system, approximately 75% of the active substance is determined as carboxylate, and another 5% - as phosphate. The bioavailability of the drug does not depend on food intake. Oseltamivir binds to plasma proteins by a maximum of 3%.

Oseltamivir is excreted primarily through the kidneys via tubular secretion as oseltamivir carboxylate. The half-life of active metabolic products is 6-10 hours. A maximum of 20% of the active component is excreted through the intestines.

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Dosing and administration

Method for preparing a medicinal suspension from Tamiflu powder: shake the closed bottle with the medicine, then measure out 52 ml of water, which is then added to the powder. After this, close the container tightly with a lid and shake for 15 seconds until an equilibrium suspension appears. Then remove the lid from the bottle, insert a special adapter into the neck and close it again. It is recommended to mark the date when the suspension was prepared on the label so as not to forget.

Adolescents and adults are usually prescribed the following dosages: 75 mg of the drug 2 times a day. A maximum of 150 mg of the drug is allowed per day (it should also be taken into account that increasing the daily dosage does not increase the effectiveness of the drug).

As a means of post-exposure prophylaxis of influenza for children and adults weighing 40+ kg, 75 mg of the drug per day for 10 days is usually prescribed. As a means of seasonal prophylaxis against influenza, the drug is prescribed in the same dosage daily throughout the epidemic period. Studies have shown that Tamiflu can be taken for 6 weeks without any health risks.

Dosages prescribed for children (the child must be at least 1 year old): children weighing less than 15 kg should take 30 mg at a time. Children weighing 15-23 kg should take 45 mg of the drug at a time. Children weighing 23-40 kg should take 60 mg of the drug. The number of doses per day is 2 times. The duration of the treatment course is 5 days.

Children aged 6-12 months in case of a flu pandemic should take the medicine in a calculated dosage of 3 mg/1 kg of weight 2 times a day, exclusively with the permission of a pediatrician. The course of treatment lasts 5 days.

The capsules of the medicine should be swallowed without chewing and washed down with water. Tamiflu can be taken regardless of food. The duration of treatment and the size of the dose are determined by the doctor.

Children over 1 year of age weighing less than 40 kg can take Tamiflu 30 or 45 capsules. When the baby cannot swallow the medicine, it is allowed to dissolve it in a spoon of plain water or sweet tea.

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Use Tamiflu during pregnancy

The drug is in category B. Preclinical studies have shown that active metabolic products and oseltamivir were absorbed into the milk of lactating rats. There is no information yet on whether the active ingredient or its active metabolite is excreted in human milk, but the amount of these substances can be 0.01 and 0.3 mg/day, respectively.

Since there is no information about the use of this drug by pregnant women, it is recommended to prescribe it during lactation or pregnancy only when the benefit from use outweighs the possible danger to the infant or fetus.

Contraindications

Among the contraindications:

• Intolerance to oseltamivir phosphate, as well as any other element of the drug;
• Chronic renal failure (regular hemodialysis or chronic peritoneal dialysis, as well as with a creatinine Cl value of less than 10 ml/min).

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Side effects Tamiflu

During treatment with Tamiflu, side effects such as nausea or vomiting may occur. They usually occur at the initial stage of therapy, go away on their own and quite quickly, so there is no need to stop taking the medication.

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Interactions with other drugs

In case of combined administration of the drug with probenecid, the process of excretion of the products of metabolism of the active substance Tamiflu through the kidneys may slow down. However, patients who do not have problems with kidney function do not need to adjust the established dosage.

Oseltamivir should be combined with caution with substances such as phenylbutazone, chlorpropamide, and methotrexate, because they are excreted in the same way, and as a result, when these drugs are taken simultaneously, the excretion process may be slowed down.

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Storage conditions

The drug in any form (except for the ready-made suspension) must be stored within the temperature range of 15-25 degrees.

The finished medicinal suspension can be stored at a temperature of 2-8 degrees for a maximum of 17 days. At 15-25 degrees – a maximum of 10 days.

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Shelf life

Tamiflu in powder form is permitted to be used for 2 years from the date of manufacture. Capsules have a 5-year shelf life.

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