Atazanavir (Adverse effects)

Atazanavir is a direct-acting antiviral drug that is often used together with other drugs, such as ritonavir or cobicistat, to treat human immunodeficiency virus (HIV) infection in adults and children who are at least 3 months old and weigh at least 10 kg. Atazanavir is in a class of drugs known as protease inhibitors. Atazanavir works by decreasing the amount of HIV in the blood. Although atazanavir does not cure HIV, it can reduce the chance of developing acquired immunodeficiency syndrome (AIDS) and HIV-related illnesses such as serious infections or cancer. Taking these medicines may decrease the risk of passing the HIV virus to other people.

Atazanavir is sometimes used to prevent infection in health care workers or other people who were accidentally exposed to HIV.

Currently, in 2020, it is being studied for the treatment of the SARS-CoV-2 coronavirus, but effectiveness studies are not yet conclusive.

MECHANISM OF ACTION

Atazanavir acts by inhibiting HIV protease, preventing the formation of mature virions in cells that are already infected and thus making it more difficult to infect other cells.

CONTRAINDICATIONS

Hypersensitivity to atazanavir.

Contraindicated in patients with severe hepatic insufficiency. Caution in patients with mild hepatic insufficiency.

Contraindicated in concomitance with: simvastatin, lovastatin, rifampicin, sildenafil for the treatment of pulmonary arterial hypertension, CYP3A4 substrates with narrow therapeutic margin (eg.quetiapine, alfuzosin, astemizole, terfenadine, cisapride, pimozide, quinidine, bepridil, triazolam, oral midazolam and ergot alkaloids, especially ergotamine, dihydroergotamine, ergonovine, methylergonovine), St. John's wort.

PHARMACOLOGICAL INTERACTIONS

Monitor possible adverse reactions if atazanavir is being administered together with: tenofovir, disoproxil, irinotecan.

Caution with: clarithromycin; ketoconazole and itraconazole (high doses greater than 200 mg/day not advisable); carbamazepine, lamotrigine, phenytoin and phenobarbital (monitor and adjust doses); pravastatin and fluvastatin; parenteral midazolam.

Monitor INR (or prothrombin time) if taking warfarin.

Azatanavir increases the concentration of: amiodarone and systemic lidocaine (caution and monitor concentration); immunosuppressants (cyclosporine, tacrolimus, sirolimus); rifabutin, buprenorphine and norbuprenorphine (monitor cognitive effects and sedation, consider reducing dose); diltiazem (reduce initial dose to 50%); verapamil.

SIDE EFFECTS

Headache, ocular jaundice, vomiting, diarrhea, abdominal pain, nausea, dyspepsia, jaundice; itching, fatigue; elevations of total bilirubin, elevations of liver enzymes CK, ALT, AST and lipase.

Decreased neutrophils.

Depression, fever, difficulty falling asleep, rash, pain or numbness in the hands or feet, muscle aches.

Other more serious side effects may include: irregular heartbeat, vision defects, pain or burning with urination, blood in the urine, swelling in the extremities, erections lasting more than 4 hours, blistering or peeling of the skin, red or inflamed eyes, canker sores in the mouth, swelling of the face or neck, very severe rashes.

BRAND NAMES

• Reyataz® (contains Ataz®)
• Evotaz® (contains Atazanavir, Cobicistat)