PFV IN with the S217H alteration has an IC50 of 900 nM, making it ten times less sensitive to raltegravir. PFV IN exhibited 10% of WT's activity and was inhibited by Raltegravir at an IC50 of 200 nM, suggesting that PFV IN is less sensitive to IN strand transfer inhibitors (INSTIs) than WT IN is. Similar to the WT enzyme, S217Q PFV IN is also susceptible to raltegravir [1]. Glucuronidation, not the liver, is the mechanism of raltegravir metabolism. With a 95% inhibitory concentration of 31±20 nM in human T cell cultures, raltegravir demonstrates strong anti-HIV-1 action in vitro. Raltegravir exhibited anti-HIV-2 activity in CEMx174 cells as well, with an IC95 of 6 nM. Glucuronidation is the main mechanism of raltegravir metabolism. Strong glucuronidase UGT1A1 inducers should not be utilized since they drastically lower raltegravir concentrations. Hepatic cytochrome P450 activity is only slightly inhibited by raltegravir. Neither CYP3A4-dependent testosterone 6-beta-hydroxylase activity nor CYP3A4 RNA expression are induced by raltegravir [2]. Magnesium and calcium have been shown to decrease raltegravir's cellular permeability [3]. Effectively preventing viral replication is possible with raltegravir and related HIV-1 integrase (IN) strand transfer inhibitors (INSTIs) [4]. Latisavue successfully suppressed SIVmac251 replication in the acutely infected human lymphoid CD4+ T cell lines MT-4 and CEMx174, suggesting an EC90 in the low nanomolar range [5].

Rateltelevir improves the viro-immunological status of nonhuman primates infected with SIVmac251 as it progresses. Raltegravir monotherapy results in an undetectable viral load in one non-human primate[5].

Absorption, Distribution and Excretion
Absorbed from the gastrointestinal tract.
Feces and urine
Approximately 83% bound to human plasma protein and is minimally distributed into red blood cells (blood-to-plasma partitioning ratio of 0.6).
The major mechanism of clearance of raltegravir in humans is glucuronidation mediated by UGT1A1, the renal clearance of unchanged drug is a minor pathway of elimination of raltegravir (9% of total dose).
Raltegravir (film-coated tablet) is absorbed with a Tmax of approximately 3 hours postdose in the fasted state. Raltegravir AUC and Cmax increase dose proportionally over the dose range 100 mg to 1600 mg. Raltegravir C12hr increases dose proportionally over the dose range of 100 to 800 mg and increases slightly less than dose proportionally over the dose range 100 mg to 1600 mg.
With twice-daily dosing, pharmacokinetic steady state is achieved within approximately the first 2 days of dosing. There is little to no accumulation in AUC and Cmax. The average accumulation ratio for C12hr ranged from approximately 1.2 to 1.6.
The absolute bioavailability of raltegravir has not been established. Based on a formulation comparison study in healthy adult volunteers, the chewable tablet has higher oral bioavailability compared to the 400 mg film-coated tablet.
In subjects who received 400 mg twice daily alone, raltegravir drug exposures were characterized by a geometric mean AUC0-12hr of 14.3 uM.hr and C12hr of 142 nM.
For more Absorption, Distribution and Excretion (Complete) data for Raltegravir (13 total), please visit the HSDB record page.

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Metabolism / Metabolites
Hepatic (UGT1A1)
In feces, only raltegravir was present, most of which is likely derived from hydrolysis of raltegravir-glucuronide secreted in bile as observed in preclinical species. Two components, namely raltegravir and raltegravir-glucuronide, were detected in urine and accounted for approximately 9 and 23% of the dose, respectively. The major circulating entity was raltegravir and represented approximately 70% of the total radioactivity; the remaining radioactivity in plasma was accounted for by raltegravir-glucuronide.
Studies using isoform-selective chemical inhibitors and cDNA-expressed UDP-glucuronosyltransferases (UGT) show that UGT1A1 is the main enzyme responsible for the formation of raltegravir-glucuronide. Thus, the data indicate that the major mechanism of clearance of raltegravir in humans is UGT1A1-mediated glucuronidation.

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Biological Half-Life
9 hours
The apparent terminal half-life of raltegravir is approximately 9 hours, with a shorter alpha-phase half-life (approximetly1 hour) accounting for much of the AUC.

Hepatotoxicity
In large clinical trials, therapy with raltegravir was associated with alanine aminotransferase (ALT) elevations in up to 10% and elevations of greater than 5 times the upper limit of normal (ULN) in 3% to 4% of patients, but these rates were similar to those in comparator groups receiving matched background optimized antiretroviral therapy without raltegravir. These elevations were not associated with clinical symptoms and generally did not require dose modification. There have been no published reports of clinically apparent cases of liver injury attributed to raltegravir. Nevertheless, the product label for raltegravir mentions hepatitis and hepatic failure as a potential adverse reactions, but without specific details. Raltegravir has also been linked to instances of Stevens Johnson syndrome and drug hypersensitivity reactions, which can be accompanied by hepatic involvement. Finally, initiation of antiretroviral therapy with raltegravir can result in the immune reconstitution syndrome which may cause a worsening or flare of an accompanying chronic hepatitis B or C in coinfected individuals.
Likelihood score: E* (unproven but suspected cause of clinically apparent liver injury).

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Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Limited information indicates that maternal doses of up to 1200 mg daily of raltegravir produce low levels in milk and would not be expected to cause any adverse effects in breastfed infants. Achieving and maintaining viral suppression with antiretroviral therapy decreases breastfeeding transmission risk to less than 1%, but not zero. Individuals with HIV who are on antiretroviral therapy with a sustained undetectable viral load and who choose to breastfeed should be supported in this decision. If a viral load is not suppressed, banked pasteurized donor milk or formula is recommended.
◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.

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Protein Binding
83%

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Interactions
Pharmacokinetic interaction with omeprazole (substantially increased raltegravir peak plasma concentrations and area under the concentration-time curve (AUC)).
Pharmacokinetic interaction with rifabutin (increased raltegravir peak plasma concentrations and AUC).
Pharmacokinetic interaction with rifampin (decreased raltegravir plasma concentrations and AUC); rifampin is a strong inducer of UGT 1A1. If raltegravir is used in adults receiving rifampin, dosage of raltegravir film-coated tablets should be increased ... twice daily and patients monitored closely for virologic response.
Concomitant use of raltegravir and rifapentine is not recommended. HIV-infected tuberculosis patients treated with rifapentine have a higher rate of tuberculosis relapse than those treated with other rifamycin-based tuberculosis regimens; an alternative antimycobacterial agent is recommended in HIV-infected patients.
For more Interactions (Complete) data for Raltegravir (17 total), please visit the HSDB record page.

[1]. Molecular mechanisms of retroviral integrase inhibition and the evolution of viral resistance. Proc Natl Acad Sci U S A, 2010. 107(46): p. 20057-62.

[2]. Combined Medication of Antiretroviral Drugs Tenofovir Disoproxil Fumarate, Emtricitabine, and Raltegravir Reduces Neural Progenitor Cell Proliferation In Vivo and In Vitro. J Neuroimmune Pharmacol. 2017 Dec;12(4):682-692.

[3]. Raltegravir: the first HIV type 1 integrase inhibitor. Clin Infect Dis. 2009 Apr 1;48(7):931-9.

[4]. Divalent metals and pH alter raltegravir disposition in vitro. Antimicrob Agents Chemother. 2012 Jun;56(6):3020-6.

[5]. Structural and functional analyses of the second-generation integrase strand transfer inhibitor dolutegravir (S/GSK1349572). Mol Pharmacol. 2011 Oct;80(4):565-72.

[6]. Response of a simian immunodeficiency virus (SIVmac251) to raltegravir: a basis for a new treatment for simian AIDS and an animal model for studying lentiviral persistence during antiretroviral therapy. Retrovirology, 2010. 7: p. 21.

Raltegravir is a pyrimidone that is pyrimidin-4(3H)-one in which the hydrogens at positions 2, 3, 5 and 6 are replaced by 2-[(5-methyl-1,3,4-oxadiazole-2-carbonyl)amino]propan-2-yl, methyl, hydroxy, and N-[(4-fluorophenyl)methyl]aminoacyl groups, respectively. It is an antiretroviral drug used for treatment of HIV infection. It has a role as an antiviral drug and a HIV-1 integrase inhibitor. It is a 1,2,4-oxadiazole, a dicarboxylic acid amide, a member of monofluorobenzenes, a pyrimidone, a hydroxypyrimidine and a secondary carboxamide.
Raltegravir is an antiretroviral drug produced by Merck & Co., used to treat HIV infection. It received approval by the U.S. Food and Drug Administration (FDA) on 12 October 2007, the first of a new class of HIV drugs, the integrase inhibitors, to receive such approval.
Raltegravir is a Human Immunodeficiency Virus Integrase Strand Transfer Inhibitor. The mechanism of action of raltegravir is as a HIV Integrase Inhibitor.
Raltegravir is an integrase inhibitor, the first of the class of antiviral agents active against the human immunodeficiency virus (HIV) that targets the viral integrase. Raltegravir is used in combination with other antiretroviral agents in the treatment of HIV infection. Raltegravir has not been linked convincingly to serum aminotransferase elevations during therapy or to episodes of acute, clinically apparent liver injury.
Raltegravir has been reported in Stachybotrys chartarum with data available.
Raltegravir is a small molecule with activity against human immunodeficiency virus (HIV). Raltegravir is an integrase inhibitor that blocks the integration of the viral genome into the host DNA, a critical step in the pathogenesis of HIV.
A pyrrolidinone derivative and HIV INTEGRASE INHIBITOR that is used in combination with other ANTI-HIV AGENTS for the treatment of HIV INFECTION.
See also: Raltegravir Potassium (has salt form).

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Drug Indication
For the treatment of HIV-1 infection in conjunction with other antiretrovirals.
FDA Label
Isentress is indicated in combination with other anti-retroviral medicinal products for the treatment of human immunodeficiency virus (HIV 1) infection.
Treatment of human immunodeficiency virus (HIV-1) infection

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Mechanism of Action
Raltegravir inhibits HIV integrase to prevent the viral genome being incorporated into the human genome. Raltegravir is primarily metabolized by glucuronidation.
Raltegravir inhibits the catalytic activity of HIV-1 integrase, an HIV-1 encoded enzyme that is required for viral replication. Inhibition of integrase prevents the covalent insertion, or integration, of unintegrated linear HIV-1 DNA into the host cell genome preventing the formation of the HIV-1 provirus. The provirus is required to direct the production of progeny virus, so inhibiting integration prevents propagation of the viral infection. Raltegravir did not significantly inhibit human phosphoryltransferases including DNA polymerases alpha, beta, and gamma.

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Therapeutic Uses
Pyrrolidinones
ISENTRESS (raltegravir) is indicated in combination with other antiretroviral agents for the treatment of human immunodeficiency virus (HIV-1) infection. /Included in US product label/
ISENTRESS (raltegravir) is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection in children and adolescents 2 years of age and older and weighing at least 10 kg. /Included in US product label/
/EXPERIMENTAL THER/ /Investigators/ describe five patients with HIV-2 infection (four antiretroviral-experienced and one antiretroviral-naive) treated with a regimen containing raltegravir. All responded to treatment as demonstrated by viral load and CD4(+) T-cell count monitoring. /This/ series confirms the clinical effectiveness of raltegravir in HIV-2-infected patients when given with other antiretrovirals to which the virus is susceptible.
/EXPERIMENTALTHER VET/ Feline leukemia virus (FeLV) is a gammaretrovirus that is a significant cause of neoplastic-related disorders affecting cats worldwide. Treatment options for FeLV are limited, associated with serious side effects, and can be cost-prohibitive. The development of drugs used to treat a related retrovirus, human immunodeficiency virus type 1 (HIV-1), has been rapid, leading to the approval of five drug classes. Although structural differences affect the susceptibility of gammaretroviruses to anti-HIV drugs, the similarities in mechanism of replication suggest that some anti-HIV-1 drugs may also inhibit FeLV. This study demonstrates the anti-FeLV activity of four drugs approved by the US FDA (Food and Drug Administration) at non-toxic concentrations. Of these, tenofovir and raltegravir are anti-HIV-1 drugs, while decitabine and gemcitabine are approved to treat myelodysplastic syndromes and pancreatic cancer, respectively, but also have anti-HIV-1 activity in cell culture. Our results indicate that these drugs may be useful for FeLV treatment and should be investigated for mechanism of action and suitability for veterinary use.

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Drug Warnings
Severe, potentially life-threatening skin reactions have been reported, including some fatalities. Stevens-Johnson syndrome, toxic epidermal necrolysis, and hypersensitivity reactions characterized by rash, constitutional findings, and organ dysfunction (including hepatic failure) have occurred.
Raltegravir and any other suspect agents should be discontinued immediately if signs or symptoms of severe skin or hypersensitivity reactions occur, including (but not limited to) severe rash or rash accompanied by fever, general malaise, fatigue, muscle or joint aches, blisters, oral lesions, conjunctivitis, facial edema, hepatitis, eosinophilia, or angioedema. Clinical status, including liver aminotransferases, should be monitored and appropriate therapy initiated. A life-threatening reaction could occur if there is a delay in discontinuing raltegravir or other suspect agents after the onset of severe rash.
During initial treatment, patients who respond to antiretroviral therapy may develop an inflammatory response to indolent or residual opportunistic infections (e.g., Mycobacterium avium, M. tuberculosis, cytomegalovirus (CMV), Pneumocystis jiroveci (formerly P. carinii), varicella-zoster virus (VZV)); this may necessitate further evaluation and treatment. Autoimmune disorders (e.g., Graves' disease, polymyositis, Guillain-Barre syndrome) have been reported to occur in the setting of immune reconstitution; the time to onset is more variable and can occur many months after initiation of antiretroviral therapy.
Individuals with phenylketonuria (i.e., homozygous genetic deficiency of phenylalanine hydroxylase) and other individuals who must restrict their intake of phenylalanine should be advised that raltegravir chewable tablets contain aspartame (NutraSweet), which is metabolized in the GI tract to phenylalanine. Each 25-mg chewable tablet provides approximately 0.05 mg of phenylalanine and each 100-mg chewable tablet provides approximately 0.1 mg of phenylalanine.
For more Drug Warnings (Complete) data for Raltegravir (12 total), please visit the HSDB record page.

C20H21FN6O5

444.42

444.155

518048-05-0

Raltegravir potassium;871038-72-1;Raltegravir sodium;1292804-07-9;Raltegravir-d4;2712343-38-7

54671008

White to off-white solid powder

1.5±0.1 g/cm3

1.651

-0.68

3

9

6

32

836

0

CZFFBEXEKNGXKS-UHFFFAOYSA-N

InChI=1S/C20H21FN6O5/c1-10-25-26-17(32-10)16(30)24-20(2,3)19-23-13(14(28)18(31)27(19)4)15(29)22-9-11-5-7-12(21)8-6-11/h5-8,28H,9H2,1-4H3,(H,22,29)(H,24,30)

N-[2-[4-[(4-fluorophenyl)methylcarbamoyl]-5-hydroxy-1-methyl-6-oxopyrimidin-2-yl]propan-2-yl]-5-methyl-1,3,4-oxadiazole-2-carboxamide

MK-0518; MK0518; MK 0518; MK-0518; Raltegravir; trade name: Isentress

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product requires protection from light (avoid light exposure) during transportation and storage.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.63 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (5.63 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (5.63 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 30% PEG400+0.5% Tween80+5% Propylene glycol : 30 mg/mL

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 (Please use freshly prepared in vivo formulations for optimal results.)