Elvitegravir - Dosage | Interactions | Effects
HIV-1 integrase is an enzyme that allows the HIV virus to be incorporated into the DNA genome of the host, resulting in viral replication and spread of infection. In this way, Elvitegravir stops HIV virus from multiplying. Unfortunately, it cannot remove all the amount of HIV from the body but it can help patients live longer. It has been approved by the FDA since 2012.
Human clinical trials have shown that Elvitegravir successfully suppresses virus replication and multiplication even after 144 weeks of regular taking. Resistance of HIV virus to this drug has not been observed during these 144 weeks and that result is quite promising, considering that most viruses develop resistance mechanisms for almost all antiviral drugs. Resistance is phenomenon that drug effects get weaker over the time.
Its advantage is that it is administered once a day and it does not exhibit serious side effects in contrast to other anti-HIV drugs.
Elvitegravir is one of the four active substances in the medicinal product called Stribild (along with cobicistat, emtricitabine and tenofovir). Stribild is approved by FDA as a first line treatment for HIV-1 infection.
Precautions and contraindications
According to FDA there are no contraindications for this drug.
Caution should be exercised in the following situations:
- In patients who are taking cobicistat (a drug that increases the effects of HIV-protease inhibitors). Cobicistat is often combined with ritonavir while the ritonavir is also often combined with Elvitegravir. In this situation, your doctor should make decision based on evaluation of benefits and risks of combining these drugs.
- In patients with severe hepatic impairment. Human trials have shown that the metabolism of this drug (which has a direct influence on its efficiency) does not change in patients with mild or moderate liver damage. However, there are no data from the use of this drug in patients with severe hepatic impairment and therefore use of Elvitegravir in patients with severe hepatic impairment should be avoided.
Immune reconstitution syndrome (occurrence of the inflammatory reactions to asymptomatic/residual opportunistic infections) has been also reported in patients taking this drug. Most common consequences of this syndrome are polymyositis, Guillain-Barre syndrome, and Graves' disease.
Drugs used for the treatment of epilepsy (carbamazepine, phenobarbital, phenytoin and oxcarbazepine) are potent inducers of CYP3A enzyme and may accelerate metabolism of Elvitegravir which significantly reduces its concentration and efficiency.
Dose adjustment isn't required for patients with impaired renal function (including severe damage) as Elvitegravir is primarily metabolized in the liver.
Elvitegravir exists in the form of tablets and come in two different strengths (85 mg and 150 mg).
A dose of 85 mg is used when the drug is combined with atazanavir or lopinavir, while the dose of 150 mg is used if the drug is combined with a darunavir or fosamprenavir.
It should be taken with food in order to reduce the risk of digestive problems.
Elvitegravir, pregnancy and breastfeeding
Due to the risk of HIV transmission from mother to child, pregnancy should be avoided if you have HIV infection.
Keep in mind that Elvitegravir reduces the effectiveness of oral contraceptives, and it is necessary to use other forms of birth-control methods while on therapy.
Breastfeeding mothers infected with HIV should avoid breastfeeding their infants, due to the risk of virus transmission to the child.
Elvitegravir should not be combined with CYP3A inducers because these drugs reduce its effectiveness.
CYP3A inducers include:
- Drugs used for the treatment of tuberculosis (rifampin and rifabutin)
- Corticosteroids, such as:
- St. John's Wort
Most of the data concerning adverse effects come from a study that was conducted on the 354 patients who were taking Elvitegravir during 96 weeks. That was a randomized, double-blind and controlled study but because of the small number of patients, it is necessary to wait for the results of post-marketing studies in order to identify all the side effects of this drug.
The most frequently reported adverse events in patients taking Elvitegravir include:
- Diarrhea (7%)
- Nausea (4%)
- Headache (3%)
Less than 2% of patients experienced following adverse reactions:
- Epigastric pain or discomfort
Suicidal thoughts and depression have occurred in less than 1% of patients.