After injection into the muscle, the substance reaches highest plasma levels after three to four days.Independently of the mode of application, rilpivirine is almost completely bound to plasma proteins (99.7%), mostly to albumin. It is metabolised mainly by the liver enzyme CYP3A4. Metabolites include several oxidation products, glucuronides, and glucuronides of oxidized metabolites. The biological half-life is approximately 45 hours for the tablets and 13 to 28 weeks for the injection.Elimination has only been studied for oral administration: Most of the drug is excreted via the faeces (85%), partly in unchanged form (25%), partly in form of its metabolites (60%). A minor amount is excreted via the urine (6%), almost exclusively as metabolites. Fixed-dose combinations
A fixed-dose medication combining rilpivirine with emtricitabine and tenofovir disoproxil (TDF) was approved by the U.S. Food and Drug Administration (FDA) in August 2011 under the brand name Complera, and was approved for use in the European Union with the brand name Eviplera in November 2011. This combination has been shown to have higher rates of virologic failure than emtricitabine/tenofovir/efavirenz in people with baseline HIV viral loads greater than 100,000 copies/mm3.A fixed-dose medication combining rilpivirine with emtricitabine and tenofovir alafenamide (TAF) was approved for use in the US in March 2016 with the brand name Odefsey.Dolutegravir/rilpivirine, sold under the brand name Juluca, is a fixed-dose combination antiretroviral medication for the treatment of HIV/AIDS. It was approved for use in the United States in November 2017 and for use in the European Union in May 2018.
Some of these drugs also induce the enzyme UGT1A1 and thus reduce blood plasma concentrations of cabotegravir, further compromising the effectiveness of this combination therapy.It is also contraindicated in combination with proton pump inhibitors because the increased gastric pH causes decreased rilpivirine absorption from the gut, with similar consequences as with CYP3A4 inducers. Adverse effects
The most common side effects of the injectable formulation are reactions at the injection site (in up to 84% of patients) such as pain and swelling, as well as headache (up to 12%) and fever or feeling hot (in 10%). Less common (under 10%) are depressive disorders, insomnia, and rashes. The most common side effects of the tablets are also depressive disorders (4.1%), headache (3.5%), insomnia (3.5%) and rashes (2.3%). All of these side effects occurred under combination therapies of rilpivirine with one or more other drugs against HIV. QT prolongation of the heart rhythm has been observed at very high doses, but is not clinically relevant at standard doses of the drug. Pharmacology
Mechanism of action
Rilpivirine is a non-nucleoside reverse transcriptase inhibitor (NNRTI). Pharmacokinetics
When taken by mouth, rilpivirine reaches highest levels in the blood plasma after about four to five hours. Taking the drug without food lowers its plasma levels by 40% as compared to taking it with food, which is considered to be clinically relevant. Therefore, patients are advised to take the medication together with a meal.