Tivicay (dolutegravir) Cost, Side Effects, Drug Interactions | Tammy Nguyen, PharmD | RxEconsult
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Tivicay (dolutegravir) Cost, Side Effects, Drug Interactions Category: Viral Infections by - October 4, 2013 | Views: 13675 | Likes: 0 | Comment: 0  

Tivicay | dolutegravir

Medication Class: Antiretroviral Agent, Integrase Inhibitor
Manufacturer: ViiV Healthcare
Approval Date: August 2013

Tivicay (dolutegravir) Uses, Dosages, Side effects, Drug Interactions

What is Tivicay and how does it work

Tivicay is a human immunodeficiency virus type 1 (HIV-1) integrase strand transfer inhibitor (INSTI). It works by inhibiting HIV integrase, which is an enzyme that is needed for the virus to multiply. Therefore, this prevents virus from multiplying and decreases the activity of the virus.

What does Tivicay Treat

Tivicay is FDA approved to be used in combination with other antiretroviral agents for the treatment of HIV-1 infection. HIV infects the white blood cells in the human immune system. This leads to low levels of important white blood cells such as CD4+ T cells. The number of CD4+ cells measure the severity of the infection and is often used in studies as an outcome for treatment.  

Tivicay is approved for both adults and children over the age of 12 and in those that weight over 40 kilograms.

How is HIV treated

The treatment regimen for HIV usually involves three separate drugs. Two of these drugs are often referred as the “background” or “backbone” treatment because they are from the same class of antiretrovirals known as nucleoside reverse transcriptase inhibitors (NRTI), while the third drug is from a different class. There are now combinations of these medications in order to decrease the pill burden for patients.

How well does Tivicay work

In the analyses from two clinical trials on patients that never received prior antiretroviral treatments, the results were comparable between the two studies. In the first study, 822 subjects received either dolutegravir (Tivicay) 50 mg once daily or raltegravir (Insentress) 400 mg twice daily, which is another integrase inhibitor. Both groups were also given the same dose of dual background treatment [either abacavir (Ziagen) and lamivudine (Epzicom) or emtricitabine/tenofovir (Truvada)]. In the second study, 833 subjects received either Tivicay 50 mg once daily with a fixed dose of abacavir (Ziagen) and lamivudine (Epzicom) or a fixed-dose efavirenz/emtricitabine/tenofovir (Atripla). In both studies, Tivicay was able to increase CD4+ (white blood cells that are an important part of our immune system) counts as effectively other treatments after 48 weeks.

In another study on patients who have received antiretroviral treatments in the past but not an integrase inhibitor, 719 patients were given either Tivicay 50 mg once daily or raltegravir 400 mg twice daily. Both groups were given the same supplementary therapy necessary to fulfill the background treatment regimen. The Tivicay group had a higher increase in CD4+ counts when compared with the raltegravir group.

What are interesting facts about Tivicay

  • Tivicay is primarily metabolized via UGT1A1, which is a gene that encodes for an enzyme that is part of a pathway that transforms Tivicay and other small molecules into water-soluble extractable metabolites.
  • Tivicay will not work in patients that are resistant to integrase strand transfer inhibitors due to an integrase strand transfer inhibitor (INSTI)-resistance substitutions into the virus. These are substitutions of amino acids into the genes of the virus that makes it resistant to the use of Tivicay and other similar drugs.
  • Redistribution and accumulation of body fat have been reported in patients treated with combination antiretroviral therapy.
  • The most common adverse effects are insomnia (trouble falling asleep) and headaches.

What is the dosage of Tivicay

Dosage form: 50 mg tablets (yellow, round, film-coated, biconvex tablets debossed with SV 572 on one side and 50 on the other side)

Dosing: Patients that never received any treatment with any antiretroviral or any integrase strand transfer inhibitor should start with 50 mg once daily. However, the frequency will need to be increased to 50 mg twice daily if they are also taking certain medications that will increase the breakdown of Tivicay such as efavirenz, fosamprenavir/ritonavir, tipranavir/ritonavir, rifampin, or if they have used other integrase strand transfer inhibitors before developed resistance.

What are the side effects of Tivicay

Common: Headache, insomnia,  and increase in cholesterol and triglyceride level. Hyperglycemia (high blood sugar) can also occur. 

Serious: Increase in liver enzymes (ALT/AST), hepatitis (inflammation of the liver), increase in serum bilirubin, hypersensitivity reactions, and renal impairment can occur. 

Drug Interactions

Dofetilide: Concurrent use of dolutegravir with dofetilide is contraindicated because of serious and life-threatening adverse events, such as QT prolongation and torsade de pointes (abnormal heart beats).

Non-nucleoside reverse transcriptase inhibitors: These drugs increase the breakdown of Tivicay which decreases the amount of Tivicay in the body. Non-nucleoside reverse transcriptase inhibitors are another type of antiretroviral that block the activity of reverse transcriptase, which is needed for virus multiplication.

Recommendations for using Tivicay with Non-nucleoside reverse transcriptase inhibitors:

  • Etravirine: Tivicay should not be used with etravirine without also providing the patient with atazanavir/ritonavir, darunavir/ritonavir, or lopinavir/ritonavir
  • Efavirenz: A 50% dose increase to 50 mg twice a day is recommended.
  • Nevirapine: Tivicay use with nevirapine should be avoided.

Protease Inhibitors: Fosamprenavir/ritonavir and Tipranavir/ritonavir increase the breakdown of Tivicay which will decrease its efficacy. Therefore, an increase in dosage to 50 mg twice a day will be needed if combined with these drugs. Protease inhibitors prevent the virus from multiplying by blocking the production of virus particles.

Oxcarbazepine, phenytoin, phenobarbital, carbamazepine, and St. John’s wort also increase the breakdown of Tivicay and should be avoided if possible.

Medications that contain polyvalent cations (positive charges) such as antacids, sucralfate, oral iron supplements, oral calcium supplements, and buffered medications (such as buffered aspirin median) should be administered with Tivicay. Tivicay should be administered 2 hours before or 6 hours after taking one of these medications.

Metformin: Tivicay prevents the breakdown of metformin. Close monitoring and possible dose reductions of metformin may be needed due to increase levels of metformin in the body.

What is the cost of Tivicay

The cost of Tivicay is $1410 a month (for 30 tablets).

How to obtain prescription assistance for Tivicay

Patients can enroll in a savings program where patients can save up to $400 for a monthly supply of Tivicay.

References

Tivicay package insert and complete prescribing information

 

 

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