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Nelfiner
Last reviewed: 04.07.2025
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Nelfiner is an antiviral drug with direct therapeutic effect. It belongs to the group of drugs that inhibit protease activity.
HIV protease is the enzyme required to perform the proteolytic cleavage that occurs on polyprotein viral precursors to form the proteins that are the building blocks of active HIV. The cleavage of such polyproteins is essential for subsequent virus formation.
The nelfinavir component is synthesized with the active region of HIV protease and prevents the cleavage of polyproteins. As a result, immature virus particles are formed that cannot infect surrounding cells.
Release form
The drug is released in the form of tablets with a volume of 0.25 g.
Pharmacodynamics
Administration of the drug together with other antiviral substances reduces the intraserum viral load and increases the number of CD4 cells. Analysis of previous and current tests confirms that Nelfiner reduces the rate of progression of the pathology.
The antiviral effect of the drug in vitro was noted in chronic or active phase of HIV infection in the lymphocyte line with monocytes, and also lymphoblastic cells with macrophages in the peripheral blood. The nelfinavir component affects a large number of clinical isolates, as well as laboratory strains of HIV-1 subtypes with HIV-2, and also in relation to the ROD type strain.
The drug demonstrates synergistic and additive effects as an element of 2- and 3-complex treatment regimens (including substances that inhibit the action of reverse transcriptase), without potentiating their cytotoxicity.
In vitro processes yielded HIV isolates with reduced sensitivity to nelfinavir. Genotyping of the viral form whose sensitivity was reduced ninefold revealed a specific substitution of aspartic acid (type D) by asparagine (type N) within the HIV protease, supplemented by 30 amino acid fragments (type D30N).
Cross-resistance between reverse transcriptase inhibitors and nelfinavir is unlikely because these drugs have different enzyme targets. HIV isolates resistant to nucleoside analogues and non-nucleoside components of reverse transcriptase inhibitors retain their susceptibility to nelfinavir in vitro.
Pharmacokinetics
With a single or multiple administration of 0.5-0.75 g of the substance (2 or 3 tablets of the drug) with food, it usually takes 2-4 hours to obtain the plasma Cmax level. After multiple administration of 0.75 g at 8-hour intervals for 28 days (equilibrium values), the plasma Cmax values were 3-4 mcg/ml, and Cmin (immediately before taking a new portion) was 1-3 mcg/ml.
Bioavailability rates for the drug are unknown, but radiolabel testing, given the large amounts of metabolic elements found in urine, suggests that approximately 78% of the ingested dose is absorbed.
Taking the drug with food increases its plasma level twofold/threefold (compared to taking it on an empty stomach). The fat content of food does not affect the intensity of the increase in plasma values of the drug when taken with food.
The calculated distribution volume (in the range of 2-7 l/kg) is higher than the total volume of fluid inside the body, from which it can be concluded that nelfinavir penetrates into tissues in large quantities. In the serum, the substance undergoes almost complete (98%) protein synthesis. High plasma values of saquinavir increase the values of nelfinavir in free form.
With a single administration of 0.75 g of 14C-nelfinavir, its unchanged element was equal to 82-86% of the intraplasma radioactivity. In the plasma, the main metabolic component and several additional ones formed during oxidation are recorded. The main oxymetabolite in vitro tests has an antiviral effect similar to the original element. In vitro, the metabolic processes of the drug are realized with the help of many isoenzymes of hemoprotein P450, including CYP3A.
The clearance rate after a single (in the range of 24-33 l/hour) and repeated administration (in the range of 26-61 l/hour) indicates high intrahepatic bioavailability of the drug. The plasma half-life (terminal stage) is usually 2.5-5 hours. A significant portion of the orally administered 0.75 g dose, which contains 14C-nelfinavir, is found in feces (87%); fecal radioactivity is associated with the labeled active element (22%), as well as many of its oxymetabolites. Only 1-2% of the used portion is found in urine (mainly unchanged nelfinavir).
In children aged 2-13 years, the clearance rate is approximately two to three times higher than in adults. The use of Nelfiner tablets in doses of approximately 20-30 mg/kg 3 times a day with food leads to equilibrium plasma values similar to those in adults taking 0.5-0.75 g of the drug 3 times a day.
Dosing and administration
The medication is taken orally, often with food. Teenagers over 13 years of age and adults are prescribed 0.75 g of the medication per day (1 tablet three times a day).
Children aged 2-13 years are required to take 20-30 mg/kg 3 times a day.
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Use Nelfinera during pregnancy
There is no information regarding the use of nelfinavir during pregnancy, so the prescription of the drug during this period is allowed only under strict indications.
There is no information regarding the excretion of the drug with breast milk. Breastfeeding is not performed when using Nelfiner.
Contraindications
Contraindicated for use by individuals with severe intolerance to any of the components of the drug.
Side effects Nelfinera
Side effects from the use of the drug are mostly of weak intensity. Diarrhea is the most common.
Rarely, such disorders as bloating, abdominal pain, nausea, asthenia, epidermal rash, increased lymphocyte count, decreased neutrophil count, and increased ALT and CPK activity develop.
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Overdose
There is only limited information regarding acute Nelfiner poisoning.
There is no antidote for the drug. It can be removed by gastric lavage and induction of vomiting. Unabsorbed substance is excreted using activated carbon. Since a significant portion of nelfinavir is synthesized with intraplasmic protein, the likelihood of dialysis effectiveness is extremely low.
Interactions with other drugs
The metabolism of nelfinavir is partially mediated by hemoprotein P450 3A (CYP3A element). Although nelfinavir does not significantly inhibit the effect of CYP3A (compared to other inhibitors - ritonavir, indinavir or ketoconazole), it should be combined with substances that induce the action of CYP3A or with potentially toxic drugs whose metabolism is carried out with the participation of CYP3A.
Other antiviral substances.
Because didanosine must be taken on an empty stomach, Nelfiner is taken with food - 2 hours before or 1 hour after didanosine administration.
Agents that induce the action of metabolic enzymes.
Medicines with a strong inducing effect on the CYP3A element (nevirapine, phenytoin and rifampicin with carbamazepine, as well as phenobarbital) can reduce plasma values of nelfinavir. Therefore, if a person using Nelfiner needs therapy with the above-mentioned drugs, it is necessary to select an alternative to them.
The combined administration of the drug with rifabutin requires a reduction in the dosage of the latter by half.
Other possible interactions.
The drug increases plasma levels of terfenadine, so they cannot be combined to prevent the development of life-threatening or severe arrhythmia.
Because there is a possibility of similar drug interactions with cisapride and astemizole, they are also not used in combination.
Although no relevant testing has been performed, the drug should not be used together with sedatives whose metabolic processes are carried out with the participation of CYP3A (including midazolam or triazolam), because their sedative effect may be prolonged.
The drug is capable of increasing plasma levels of other drugs that are substrates of the CYP3A element (including substances that block the action of Ca channels), therefore, in such situations, patients should be carefully examined in order to diagnose symptoms of toxicity of these drugs.
The drug reduces the effectiveness of oral contraception when used in combination.
Storage conditions
Nelfiner should be stored in a place closed to small children and sunlight. Temperature values should not exceed 25°C.
Shelf life
Nelfiner can be used for a period of 24 months from the date of sale of the medicinal product.
Use in children
There is no data on the safety and medicinal efficacy of the drug when used in children under 2 years of age, so it is used in this group only in situations where the benefit from its administration is more likely than the risks of complications.
Attention!
To simplify the perception of information, this instruction for use of the drug "Nelfiner" translated and presented in a special form on the basis of the official instructions for medical use of the drug. Before use read the annotation that came directly to medicines.
Description provided for informational purposes and is not a guide to self-healing. The need for this drug, the purpose of the treatment regimen, methods and dose of the drug is determined solely by the attending physician. Self-medication is dangerous for your health.