Abacavir

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Available since: 2019-09-19

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Clinical Pharmacology

Abacavir is a nucleoside analog that inhibits HIV reverse transcriptase and selectively inhibits the replication of HIV-1 and HIV-2, including strains of HIV-1 resistant to zidovudine, lamivudine, zalcitabine, didanosine and nevirapine. Abacavir undergoes intracellular metabolism, turning into the active form, carbovir-5'-triphosphate (carbovir-TF). According to in vitro studies, the antiviral effect of the drug is due to the inhibition of HIV reverse transcriptase, which leads to a break in DNA synthesis on the RNA matrix and the cessation of HIV replication. No antagonism was observed in the antiviral activity of abacavir in cell culture when combined with nucleoside reverse transcriptase inhibitors (NRTIs) didanosine, emtricitabine, lamivudine, stavudine, tenofovir, zalcitabine or zidovudine, non-nucleoside reverse transcriptase synthesis. .
Mutations in several codons of the reverse transcriptase gene were found in the in vitro strains of HIV-1 resistant to abacavir.
(FROM) - M184V, K65R, L74V and Y115F. HIV resistance to abacavir in vitro and in vivo is formed slowly. For a clinically significant increase in the 50% inhibitory concentration (IC50) (an increase in the IC50 of 8 times relative to the “wild” virus strain), multiple mutations are required. Abacavir resistant strains may have reduced sensitivity to lamivudine, salvitabine, and / or didanosine, but remain fully susceptible to zidovudine and stavudine. Cross-resistance to abacavir and HIV or NNRTI PI is unlikely. The ineffectiveness of the first-line regimen, including abacavir, lamivudine and zidovudine, is mainly associated with a single mutation, M184V, which preserves the possibility of a wide choice of second-line therapy regimens.
Abacavir penetrates into the cerebrospinal fluid (CSF) and reduces its content of HIV-1 RNA. In combination with other antiretroviral drugs, it can prevent the development of neurological complications of HIV infection and slow down the appearance of resistant strains within the central nervous system (CNS).
Pharmacokinetics:
Suction
Abacavir is quickly and well absorbed when taken orally. The absolute bioavailability of abacavir when administered to adults is about 83%. The time to reach the maximum concentration (Tmax) when taking abacavir orally in the form of pills is about 1.5 hours, and in the form of oral solution - about 1 hour. The area under the concentration-time pharmacokinetic curve (AUC) for a tablet form of abacavir does not differ from that for abacavir as an oral solution. When taking a tableted form of abacavir orally at a dose of 300 mg 2 times a day, the maximum plasma concentration (Cmax) when the equilibrium state is reached is on average 3 μg / ml, and the AUC during the 12-hour interval between doses of doses is on average 6, 02 μg'h / ml.
After a single dose of abacavir pills at a dose of 600 mg Cmax, it averages about 4.26 mcg / ml, and AUC ∞ - an average of 11.95 mcg / h.
According to a study in 20 HIV-infected patients who took abacavir at a dose of 300 mg 2 times a day and only one dose (300 mg) before the 24-hour period for collecting samples for analysis, the geometric mean of the terminal half-life (T1 / 2) of the intracellular Carbovira-TF in the equilibrium state is 20.6 h (the same indicator for serum abacavir concentration is 2.6 h). Equilibrium pharmacokinetic parameters when taking abacavir 600 mg 1 time per day were the same as when taking abacavir 300 mg 2 times a day in a cross-design clinical study in 27 HIV-infected patients. The intracellular content of carbovir-TF in peripheral blood mononuclear cells was higher when using abacavir at a dose of 600 mg 1 time per day compared with taking abacavir 300 mg 2 times a day (AUC24, ss increase in equilibrium over 24 hours , the maximum daily concentration in the state of equilibrium (Cmax24, ss) is 99%), which indicates the possibility of such a regimen of drug administration by HIV-infected patients. The efficacy and safety of abacavir provided with a single daily dose was shown in a clinical study (CNA30021).
Eating slows down the absorption of abacavir and reduces Cmax, but does not affect AUC.Therefore, abacavir can be taken with or without food. Taking a shredded tablet with a small amount of semi-solid food or liquid does not affect the pharmacokinetics and, therefore, clinical efficacy. This conclusion is based on the physicochemical and pharmacokinetic parameters of the active substance and the water solubility of abacavir pills, it is assumed that the patient will grind and add the whole tablet to food or liquid and take it immediately inside.
Distribution and binding to plasma proteins
The volume of distribution of abacavir when administered intravenously is about 0.8 l / kg, which indicates its ability to easily penetrate into the tissue.
Studies involving HIV-infected patients showed that abacavir penetrates well into CSF, while the ratio of AUC of abacavir in CSF to AUC of abacavir in blood plasma is 30-44%. In a pharmacokinetic study of phase I, it was found that after 1.5 hours after taking abacavir at a dose of 300 mg 2 times a day, its average concentration in CSF was 0.14 mcg / ml When using abacavir at a dose of 600 mg 2 times a day, the concentration of the drug in CSF increased from 0.13 mcg / ml through 0, 5-1 h after ingestion to 0.74 mcg / ml when measured 3–4 h after ingestion of ab Avira. Thus, even if the abacavir concentration observed in the CSF 4 hours after taking the drug at a dose of 600 mg 2 times a day, is not the maximum attained with this treatment regimen, it already exceeds IC50 (0.08 mcg / ml or 0 , 26 mcmol / l) 9 times.
In vitro studies have established that at therapeutic doses, abacavir moderately (approximately 49%) binds to human plasma proteins. This suggests that the interaction of abacavir with other drugs by displacing them from the connection with plasma proteins is unlikely.
Metabolism
Abacavir is metabolized mainly in the liver, in an unchanged form is excreted by the kidneys less than 2% of the accepted dose of the drug. In humans, abacavir is metabolized mainly by the action of alcohol dehydrogenase with the formation of 5'-carboxylic acid and by conjugation with glucuronic acid with the formation of 5'-glucuronide, constituting about 66% of the total amount of the administered dose. These metabolites are excreted by the kidneys.
Removal
On average, the half-life of abacavir is about 1.5 hours. Long-term use of abacavir orally at a dose of 300 mg 2 times a day does not lead to a significant cumulation of the drug. Abacavir is eliminated through metabolism in the liver, followed by excretion of metabolites, mainly by the kidneys. About 83% of the administered dose is excreted by the kidneys as metabolites and abacavir unchanged, and the remaining amount is excreted through the intestines.
Special patient groups
Children
Abacavir is well and quickly absorbed in the form of oral solution and in the form of pills when administered in children. Plasma abacavir exposure was the same for both forms of release at the same dosage. In children receiving abacavir in the form of an oral solution in accordance with the recommended dosing regimen, plasma exposure to abacavir was similar to that in adults. In children receiving abacavir in pill form in accordance with the recommended dosing regimen, plasma abacavir exposure was higher than in children receiving abacavir in the form of oral solution due to the higher dosage in mg / kg when taking the pill. Pharmacokinetic studies in children have shown that taking the drug 1 time per day is equivalent in terms of AUC0-24 to taking the same dose of the drug divided into 2 times a day.
There is not enough safety data to recommend - the use of abacavir in children younger than 3 months. There are limited data showing that a dose of 2 mg / kg in newborns younger than 30 days provides a similar or greater value of AUC values compared with a dose of 8 mg / kg in older children.
Elderly patients
The pharmacokinetics of abacavir have not been studied in patients over 65 years of age. In the treatment of elderly patients, it is necessary to take into account more frequent abnormalities of the liver, kidneys and heart at this age, as well as comorbidities and medications taken.
Patients with impaired renal function
Abacavir is metabolized mainly in the liver, less than 2% of it is excreted by the kidneys unchanged. The pharmacokinetics of abacavir in end-stage renal failure is about the same as in normal renal function. Therefore, in violation of renal function, dose adjustment is not required.
Patients with impaired liver function
Abacavir is metabolized mainly in the liver. The results of the study of the pharmacokinetics of abacavir in patients with mild liver dysfunction (5-6 points on the Child-Pugh scale) indicate an increase in AUC by an average of 1.89 times and a half-life of 1.58 times. Abacavir metabolism does not affect the AUC of abacavir metabolites, however, the rate of their formation and elimination decreases.
Patients with impaired mild hepatic function for therapeutic purposes can take 200 mg of abacavir 2 times a day.
The pharmacokinetics of abacavir in patients with impaired liver function moderate and severe has not been studied, thus, the use of abacavir is not recommended in these groups of patients.

Indications

Treatment of HIV infection in adults and children weighing more than 14 kg as part of combination antiretroviral therapy.

Composition

1 tablet, film coated 600 mg, contains:
Active ingredient: abacavir sulfate 702.8 mg, in terms of abacavir 600 mg.
Excipients: sodium carboxymethyl starch 58 mg, colloidal silicon dioxide 11 mg, magnesium stearate 11 mg, povidone K-30 46 mg, microcrystalline cellulose 391.2 mg.
Film coating composition: Opadry II yellow 38 mg, including: hypromellose (hydroxypropylmethylcellulose) 12.92 mg, lactose monohydrate 10.64 mg, macrogol (polyethylene glycol) 4.56 mg, titanium dioxide 7.98 mg, iron dye yellow oxide 1.9 mg.

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Dosage and Administration

The drug Abacavir Canon is ingested, regardless of the meal. The drug should be prescribed by a doctor with treatment experience.
HIV infection. To ensure the accuracy of the dosage of the drug, it is recommended to swallow the tablet completely without dividing; however, as an alternative, dividing and grinding pills with the addition of a small amount of semi-solid food or liquid is allowed. The entire amount of the mixture must be taken orally immediately.
Adults and children weighing not less than 25 kg
The recommended dose of Abacavir Canon is 600 mg / day. The drug is prescribed in a dose of 300 mg (1 tablet of 300 mg or ½ tablet of 600 mg, break exactly at risk) 2 times a day or 600 mg (2 pills of 300 mg or 1 tablet of 600 mg) 1 time per day.
Special patient groups
Children
Children weighing from 14 to 25 kg
-Children weighing from 14 to 20 kg: the recommended dose of Abacavir Canon is 150 mg (1/2 tablet 300 mg, break exactly at risk) 2 times a day or 300 mg (1 tablet 300 mg) 1 time per day;
-Children weighing more than 20 kg, but less than 25 kg: The recommended dose of Abacavir Canon is 150 mg (½ pills 300 mg, break exactly at risk) in the morning and 300 mg (1 tablet 300 mg) in the evening or 450 mg (1 ½ 300 mg pills) once a day;
For children weighing less than 14 kg or patients unable to swallow pills, it is recommended to use the drug in the form of oral solution.
Patients with impaired renal function
In patients with impaired renal function dose adjustment of the drug Abacavir Canon is not required.
Patients with impaired liver function
Abacavir is metabolized primarily in the liver. The recommended dose of abacavir for patients with mild hepatic impairment (5-6 points on the Child-Pugh scale) is 200 mg 2 times a day. Given the need to use smaller doses of abacavir in patients with mild liver dysfunction, for proper dosing of the drug it is prescribed in an alternative dosage form - oral solution. There are no data on the pharmacokinetics and safety of abacavir use in patients with moderate and severe hepatic impairment. Thus, the use of abacavir in patients with impaired liver function is moderately and severely contraindicated.

Adverse reactions

The nature of other adverse reactions, other than HSR, but observed in patients taking Abacavir Canon, is not completely clear. Whether these adverse reactions are due to the use of the drug Abacavir Canon or a wide range of other drugs prescribed for the treatment of HIV infections, or whether they are due to the disease itself, has not yet been established.
Many of the following adverse reactions associated with taking the drug Abacavir Canon (nausea, vomiting, diarrhea, fever, fatigue, rash) are usually observed with the development of HRV to abacavir. therefore, when any of these symptoms appear, a careful examination of the patient is indicated to confirm the development of HLV. If Abacavir Canon was canceled due to the above symptoms and the decision was made to resume therapy with Abacavir Canon, then this can be done only under direct medical supervision.
Very rare cases of polymorphic exudative erythema, Stevens-Johnson syndrome, or toxic epidermal necrolysis have been reported in which it was impossible to exclude HLV to abacavir. In such cases, you must permanently stop taking drugs containing abacavir.
Most of the adverse reactions listed below are not limiting treatment. The frequency of occurrence is determined as follows:
very often -> 1/10,
often from> 1/100 to <1/10,
infrequently - from> 1/1000 to <1/100,
rarely from> 1/10000 to <1/1000,
very rarely - <1/10000.
Clinical research data
Metabolic and nutritional disorders
Often: loss of appetite.
Nervous system disorders
Often: headache.
Violations with moans of the gastrointestinal tract
Often: nausea, vomiting, diarrhea.
General disorders and disorders at the site of administration
Often: fever, drowsiness, fatigue.
In controlled clinical studies, it was shown that a change in laboratory parameters in the treatment with abacavir is observed infrequently, as in the control group of patients who did not receive abacavir.
Children
Safety data confirming a single dose of abacavir in children was obtained in the ARROW study (COL 105677), in which 669 children infected with HIV-1 received abacavir and lamivudine 1 or 2 times a day. No additional safety signals were detected in children who took abacavir 1 or 2 times per day compared with adults.
Post-registration surveillance data
Metabolism and nutrition disorders
Often: hyperlactatemia.
Rarely: lactic acidosis, accumulation and / or redistribution of adipose tissue. The frequency of these adverse reactions depends on many factors, including the antiretroviral drugs used in combination with abacavir.
Disorders of the gastrointestinal tract
Seldom: pancreatitis (the relationship of cause and effect with use of an abakavir is definitely not established).
Violations of the skin and subcutaneous tissue
Often: rash (in the absence of systemic manifestations).
Very rare: polymorphic exudative erythema, including Stevens-Johnson syndrome and toxic epidermal necrolysis.
There have been cases of lactic acidosis, sometimes fatal, usually associated with severe hepatomegaly and fatty liver, using nucleoside analogs.
Combined antiretroviral therapy has been associated with the redistribution of adipose tissue (lipodystrophy) in patients with HIV, including a reduction in the subcutaneous fatty layer on the face and extremities, an increase in intra-abdominal and visceral fat, an increase in mammary glands and dorsocervical fat deposition ("buffalo hump").
The use of combination antiretroviral therapy has been associated with metabolic disorders, such as hypertriglyceridemia, hypercholesterolemia, insulin resistance, hyperglycemia, and hyperlactatemia.
In HIV-infected patients with severe immunodeficiency, inflammatory reactions to asymptomatic or residual opportunistic infections may occur during the initiation of combination antiretroviral therapy. There have also been reported cases of autoimmune diseases (for example, Graves disease) that occur under conditions of immune reactivation, however, the presented periods of the disease are more diverse and these phenomena can occur many months after the start of therapy.
Cases of osteonecrosis have been reported, especially in patients with well-known risk factors, advanced stage HIV infection or long-term use of combination antiretroviral therapy. The frequency of this phenomenon is unknown.
Description of individual unwanted reactions
Hypersensitivity
Hypersensitivity reaction (HLV) to abacavir was defined as a common adverse reaction in the treatment of drugs containing abacavir. The signs and symptoms of HBP are given below. These signs and symptoms were identified during clinical studies or during post-registration follow-up. Symptoms and signs that occur in at least 10% of patients with HCV are in bold.Virtually all patients with HCV develop a fever and / or rash (usually maculopapular or urticarial) as part of the syndrome, but reactions can also occur without rash or fever. Other major symptoms include gastrointestinal, respiratory, or constitutional symptoms, such as drowsiness or malaise.
Violations of the skin and subcutaneous tissue
Rash (usually maculopapular or urticarial).
Disorders of the gastrointestinal tract
Nausea, vomiting, diarrhea, abdominal pain, ulceration of the oral mucosa.
Disorders of the respiratory system, organs of the chest and mediastinum
Shortness of breath, cough, sore throat, adult respiratory distress syndrome, respiratory failure.
Nervous system disorders
Headache, paresthesia.
Violations of the blood and lymphatic system
Lymphopenia.
Disorders of the liver and biliary tract
Increased biochemical indicators of liver function, hepatitis, liver failure.
Disorders of the musculoskeletal and connective tissue
Myalgia, myolysis, arthralgia, increased activity of creatine phosphokinase.
Kidney and urinary tract disorders
Increased serum creatinine concentration, renal failure.
General disorders and disorders at the site of administration
Fever, fatigue, malaise, edema, lymphadenopathy, arterial hypotension, conjunctivitis, anaphylactic reactions. The resumption of the drug Abacavir Canon after HPA on abacavir leads to a rapid return of symptoms within a few hours. Repeated HPV is usually more severe than the first, and may include life-threatening hypotension and death. In rare cases, reactions also occur when therapy with Abacavir Canon is resumed after it is discontinued, caused by the appearance of only one of the main symptoms of hypersensitivity (see above) and in very rare cases, this reaction occurs when Abacavir Canon is resumed in patients who No symptoms of HBV were noted (i.e., in patients who had previously been considered to be undergoing therapy with abacavir).
For more information on the clinical management of a suspected rgc case of abacavir, see the "Special Instructions" section.

Contraindications

- Hypersensitivity to abacavir or any other component of the drug;
- Children weighing less than 14 kg (for this dosage form);
- Hepatic insufficiency of moderate and severe degree (class B and C on the Child-Pugh scale), due to the lack of clinical data and the recommended dosing regimen;
- Hepatic failure mild (class A on the Child-Pugh scale), due to the inability to provide a dosing regimen;
- The period of breastfeeding;
- Lactose intolerance, lactase deficiency, glucose-galactose malabsorption.
Carefully:
Patients with a possible risk of coronary heart disease; combined use of an abakavir and ribavirin (see the section "Interaction").

Drug interactions

In vitro studies and analysis of the main metabolic pathways of abacavir indicate that its interaction with other drugs mediated by cytochrome P450 is unlikely.
Abacavir does not inhibit metabolic reactions involving the cytochrome P450 CYP3A4 isoenzyme.
In vitro studies have shown that - abacavir does not interact with drugs that are metabolized by isoenzymes CYP3A4, CYP2C9 and CYP2D6. Clinical studies have not revealed the induction of hepatic metabolism of exogenous substances under the action of abacavir. Thus, the interaction of abacavir with HIV protease inhibitors and other drugs metabolized with the participation of the main cytochrome P450 isoenzymes is unlikely.
Clinical studies have shown the absence of clinically significant interactions between abacavir, zidovudine, and lamivudine. Powerful enzyme inducers, such as rifampicin, phenobarbital, and phenytoin, when they act on UDP-glucuronyltransferase, can slightly reduce plasma abacavir concentrations.
Ethanol: ethanol slows down the metabolism of abacavir, which leads to an increase in AUC by 41%. However, the clinical significance of this change is small. Abacavir does not affect the metabolism of ethanol.
Methadone: according to pharmacokinetic studies, the use of abacavir at a dose of 600 mg 2 times a day in combination with methadone reduces Cmax of abacavir in serum by 35%, increases Tmax in serum by 1 h, but does not change AUC. The clinical significance of these changes is small.
In the same study, it was found that abacavir increases methadone systemic clearance by 22%. In most cases, these changes are also regarded as clinically insignificant, but in certain situations, it may be necessary to change the dose of methadone.
Retinoids: retinoids, for example, isotretinoin, are eliminated with the participation of alcohol dehydrogenase, so they can interact with abacavir, but so far no special studies have been conducted.
Ribavirin: due to the fact that abacavir and ribavirin have the same phosphorylation pathways, an interaction between these substances is expected, which can lead to a decrease in intracellular phosphorylation of ribavirin metabolites and potentially leads to a decrease in the probability of achieving a sustained virological response in hepatitis C coinfected HIV-infected patients treated with pegylated interferon and ribavirin. Published controversial data on the simultaneous use of abacavir and ribavirin. According to some data, it is assumed that HIV-infected patients receiving abacavir-containing drugs may have a risk of a low response rate to antiviral therapy with pegylated interferon and ribavirin. Care must be taken while taking these drugs.

Special instructions

The drug should be prescribed by a physician experienced in treating HIV infection.
Each patient should read the instructions for use.
Hypersensitivity
The use of the drug Abacavir Canon is associated with the risk of developing HRC characterized by the appearance of fever and / or rash and other symptoms indicating a multiple organ failure. HBV can be life-threatening and in rare cases when appropriate treatment is not prescribed, it can be fatal. The risk of developing HCV with the use of the drug Abacavir Canon is significantly increased in patients with a positive test result for the presence of the HLA-B * 5701 allele. However, HPA on abacavir was noted with a lower frequency in patients who are not carriers of this allele.
The following rules should be followed.
- A study should be conducted on the presence of the HLA-B * 5701 allele before initiating therapy with Abacavir Canon and also before resuming therapy with Abacavir Canon in patients with an unknown status regarding the HLA-B * 5701 allele, who had previously well tolerated therapy with abacavir.
- It is not recommended to use the drug Abacavir Canon in patients with the HLA-B * 5701 allele or in patients in whom HBV was suspected during the use of any other drug containing abacavir regardless of status regarding HLA-B * 5701.
- Each patient should be reminded that it is necessary to read the instructions for use enclosed in the packaging of the drug Abacavir Canon. Also, patients should be reminded that you must constantly carry a warning card attached to the drug.
- In all patients receiving therapy with Abacavir Canon, the clinical diagnosis of suspected HCF should remain the basis for a clinical decision.
- If the Abacavir drug is suspected to have HCV therapy, the canon should be immediately discontinued even in the absence of the HLA-B allele * 5701.A delay in discontinuing therapy with Abacavir Canon after the onset of HBR can lead to a life-threatening reaction.
- Patients who have developed HBV should be informed about the need to transfer the remaining pills of the drug Abacavir Canon to your doctor in order to avoid resuming the use of abacavir.
- The resumption of the use of drugs, the contents of abacavir, after suspected HPC on abacavir can lead to a rapid return of symptoms within a few hours, which may include life-threatening hypotension and death.
- When considering the resumption of therapy with abacavir after discontinuation of treatment with any drug containing abacavir for any reason, the reason for discontinuing therapy should be established, regardless of whether the patient carries the HLA-B * 5701 allele. If HRC cannot be excluded, the use of Abacavir Canon or any other drugs containing abacavir cannot be resumed.
- If the FPGA is excluded, resumption of therapy with Abacavir Canon is possible. In rare cases, patients who have discontinued abacavir for reasons other than the symptoms of HRSH also developed life-threatening reactions within a few hours after resuming therapy with abacavir (see the section entitled “Description of Individual Adverse Reactions”).
Patients should be informed about the possibility of developing HCV when resuming therapy with Abacavir Canon or other drugs containing abacavir should be carried out only if there is quick access to medical care.
Clinical picture of rgch on abacavir
Abacavir HRCs have been well studied in clinical studies and during post-registration follow-up. Symptoms usually appear during the first 6 weeks (the median time of onset of this reaction is 11 days) after the initiation of therapy with abacavir, however, these reactions may develop at any time point during treatment.
Virtually all of the HPA reactions to abacavir include fever and or a rash as part of the syndrome. Other signs and symptoms, which are noted as manifestations of HPC on abacavir, include symptoms of the respiratory and gastrointestinal tract, which can lead to incorrect diagnosis of HPC as a respiratory disease (pneumonia, bronchitis, pharyngitis) or gastroenteritis (see the sections " action "," Description of individual undesirable reactions "). Patients should be closely monitored with consultations every 2 weeks, especially during the first 2 months of therapy with Abacavir Canon.
If the symptoms of abdominal infection continue, the symptoms of abacavir continue, they become more pronounced and can become life-threatening. In most cases, these symptoms disappear when you stop taking abacavir.
Lactic acidosis and severe hepatomegaly with steatosis
There are reports of the development of lactic acidosis and severe hepatomegaly with steatosis, including death, due to antiretroviral therapy of nucleoside analogues, including abacavir, taken both separately and in combination. In most cases, these complications occur in women.
Symptoms that may indicate the development of lactic acidosis include general weakness, loss of appetite, rapid weight loss of unknown etiology, gastrointestinal disorders (nausea, vomiting and abdominal pain), disorders of the respiratory system (shortness of breath and tachypnea) or neurological symptoms (including motor).
Lactic acidosis has a high mortality rate in the absence of emergency treatment and may be associated with pancreatitis, hepatic or renal failure. Lactic acidosis, as a rule, manifested itself after several months of therapy.It is necessary to discontinue therapy with nucleoside analogues in the event of symptomatic manifestations of hyperlactatemia and metabolic or lactic acidosis, progression of hepatomegaly, or a rapid increase in the activity of aminotransferases.
The use of Abacavir Canon and other abacavir-containing drugs requires caution for any patients (especially women with overweight) with hepatomegaly, hepatitis or other known risk factors for liver damage and liver steatosis (including the use of certain medications and alcohol). Patients with combined hepatitis C who receive interferon alpha and ribavirin therapy may be a particular risk group. Patients with increased risk require careful monitoring.
With the appearance of clinical or laboratory signs of lactic acidosis with or without hepatitis (hepatomegaly and steatosis may occur, even in the absence of a pronounced increase in the activity of aminotransferases), treatment with Abacavir Canon must be suspended.
Mitochondrial dysfunction
In vitro and in vivo studies have shown that nucleoside and nucleotide analogs can cause varying degrees of mitochondrial damage. There were reported cases of ittochondrial dysfunction in HIV-negative children who received intrauterine and / or after birth nucleoside analogues. The main undesirable reactions were hematological disorders (anemia, neutropenia), metabolic disorders (hyperlactataemia, hyperlipasemia). These undesirable reactions are often transient. Some late-onset neurological disorders (increased muscle tone, seizures, behavioral disorders) have been reported. Whether these neurological disorders are transitory or permanent is currently unknown. Any child, even HIV-negative, subjected to prenatal exposure to nucleoside and nucleotide analogues, must undergo a clinical and laboratory examination in order to exclude mitochondrial dysfunction in the event of the detection of relevant signs or symptoms. These data do not affect current national guidelines for the use of antiretroviral therapy in pregnant women for the prevention of vertical transmission of HIV infection.
Redistribution of subcutaneous fat
In some patients receiving combination antiretroviral therapy, redistribution and / or accumulation of subcutaneous fat may be observed, including central obesity, dorsocervical fat deposition ("buffalo hump"), reduction of the subcutaneous fat layer on the face and extremities, increase in mammary glands , increased serum lipid concentration and blood glucose concentration.
Although one or more of the above undesirable reactions associated with a common syndrome, which is often referred to as lipodystrophy, can be caused by all drugs of the HIV PI and NRTI classes. The data indicate the existence of differences between individual representatives of the indicated classes of drugs in their ability to cause these undesirable reactions.
It should also be noted that lipodystrophy syndrome has a multifactorial etiology; for example, the stage of HIV infection, old age and the duration of antiretroviral therapy play an important, perhaps synergistic role.
The long-term effects of these adverse reactions are currently unknown.
At clinical examination of patients it is necessary to pay attention to the redistribution of subcutaneous fat. Laboratory examination should include determination of serum lipid concentration and glucose concentration in the blood. In case of lipid metabolism disorders, appropriate treatment is prescribed.
Pancreatitis
There have been cases of pancreatitis, although the causal relationship with the use of abacavir has not been precisely established.
Therapy with three nucleoside reverse transcriptase inhibitors (NRTIs)
In patients with a high viral load (> 100,000 copies / ml), the administration of a triple combination containing abacavir, lamivudine and zidovudine requires special consideration.
There were cases of high frequency of virological failure and the emergence of resistance in the early stages, when a combination of abacavir with tenofovir desoproxil fumarate and lamivudine was used as a treatment regimen 1 time per day.
Liver diseases
The efficacy and safety of abacavir have not been established in patients with severe concomitant liver disease. The drug Abacavir Canon is contraindicated in patients with impaired liver function of moderate and severe.
Patients with pre-existing liver dysfunction, including active chronic hepatitis, have an increased incidence of liver dysfunction during combination antiretroviral therapy, and should be monitored in accordance with accepted practice. It is necessary to consider the possibility of stopping or stopping treatment in the event of a worsening of the disease in such patients.
Concomitant Hepatitis B or C
Patients with concomitant chronic hepatitis B or C who receive combination antiretroviral therapy have an increased risk of severe and potentially fatal adverse reactions from the liver. In the case of concomitant antiviral therapy for hepatitis B or C, you should also familiarize yourself with the appropriate instructions for use of these drugs.
Care must be taken when prescribing abacavir and ribavirin.
Kidney disease
The drug Abacavir Canon should not be administered to patients with terminal chronic renal failure.
Immunity recovery syndrome
If HIV-infected patients with severe immunodeficiency have asymptomatic opportunistic infections or their residuals at the time of the initiation of antiretroviral therapy, such therapy may lead to increased symptoms of opportunistic infections or other serious consequences. Typically, these reactions occur during the first weeks or months after the start of antiretroviral therapy. Typical examples are cytomegalovirus retinitis, generalized and / or focal infection caused by mycobacteria, and pneumonia caused by Pneumocystis jiroveci (formerly P. carinii). The appearance of any symptoms of inflammation requires immediate examination and, if necessary, treatment.
Autoimmune diseases (such as Graves' disease, polymyositis and Guillain-Barré syndrome) were observed against the background of the restoration of immunity, however, the time of primary manifestations varied, and the disease could occur many months after the start of therapy and have an atypical course.
Osteonecrosis
Although the etiology of this disease is multifactorial (including taking glucocorticosteroids, drinking alcohol, severe immunosuppression, high body mass index), osteonecrosis was most common in patients with late-stage HIV infection and / or long-term combination antiretroviral therapy. Patients should consult a doctor if they experience pain and stiffness in the joints or difficulty in moving.
Opportunistic infections
The use of Abacavir Canon or other antiretroviral drugs does not preclude the development of opportunistic infections or other complications of HIV infection, so patients should remain under the supervision of a physician experienced in treating HIV-related diseases.
HIV transmission
Conducting antiretroviral therapy, including Abacavir Canon, does not exclude the possibility of HIV transmission through sexual contact or when in contact with infected blood and therefore does not eliminate the need for proper precautions.
Myocardial infarction
As a result of a prospective observational epidemiological study to study the incidence of myocardial infarction in patients receiving combined antiretroviral therapy, an association of prior abacavir administration for 6 months with an increased risk of myocardial infarction was found. According to a generalized analysis of clinical studies, no increase in the risk of myocardial infarction associated with taking abacavir was observed. The biological mechanisms that explain the potentially increased risk are unknown. In general, the available data obtained from cohort observations and controlled clinical trials do not allow one to unambiguously determine the relationship between therapy with abacavir and the risk of myocardial infarction.
However, antiretroviral therapy, including drugs containing abacavir, should be prescribed with caution to patients with a possible risk of coronary heart disease. All measures must be taken to minimize all modifiable risk factors (such as hypertension, dyslipidemia, diabetes mellitus and smoking).
Impact on the ability to drive trans. Wed and fur .:
There is no evidence of the effect of abacavir on the ability to engage in potentially hazardous activities requiring increased attention. However, patients should be informed about the possible development of adverse reactions such as fatigue during the treatment with abacavir. They should be advised to be careful when driving and operating machinery.

Overdosage

Symptoms
In clinical studies, no adverse reactions have been identified with the use of abacavir in single doses up to 1200 mg and daily up to 1800 mg. The effect of the drug in higher doses has not been studied to date.
Treatment
In case of overdose, the patient is monitored to identify symptoms of poisoning and to start treatment promptly. If necessary, carry out symptomatic treatment. The effectiveness of peritoneal dialysis and hemodialysis for the removal of abacavir is unknown.