Atazanavir


Concise Prescribing Info
Indications/Uses
HIV-1 infection.
Dosage/Direction for Use
Adult : PO 300 mg once daily w/ ritonavir 100 mg. Alternatively: Treatment-naive patient: 400 mg once daily (if patient cannot tolerate ritonavir).
Dosage Details
Oral
HIV-1 infection
Adult: 300 mg once daily, given w/ ritonavir 100 mg. Alternatively, for treatment-naive patient: 400 mg once daily (if patient cannot tolerate ritonavir).
Child: ≥3 mth As powd: 5-<15 kg: 200 mg once daily, given w/ ritonavir 80 mg; 15-<25 kg: 2250 mg once daily, given w/ ritonavir 80 mg. >6 yr As cap/powd: 15-<20 kg: 150 mg once daily, given w/ ritonavir 100 mg; 20-<40 kg: 200 mg once daily, given w/ ritonavir 100 mg; ≥40 kg: Same as adult dose.
Renal Impairment
Treatment-experienced patient on haemodialysis: Contraindicated.
Hepatic Impairment
W/ ritonavir: Mild to severe: Contraindicated. W/o ritonavir (treatment-naive patient): Moderate (Child-Pugh category B): 300 mg daily. Severe (Child-Pugh category C): Contraindicated.
Administration
Should be taken with food.
Contraindications
Hypersensitivity. Treatment-experienced patient on haemodialysis. Mild to moderate (w/ ritonavir) and severe (w/ or w/o ritonavir) hepatic impairment. Lactation. Concomitant use w/ statins (e.g. simvastatin, lovastatin), antiarrhythmics (e.g. amiodarone, bepridil, quinidine, systemic lidocaine), antihistamines (e.g. astemizole, terfenadine), antipsychotics (e.g. pimozide, quetiapine), ergot derivatives (e.g. dihydroergotamine, ergometrine, ergotamine, methylergometrine), GI prokinetics (e.g. cisapride), sedative and hypnotics (e.g. triazolam, oral midazolam), α1-adrenergic antagonists (e.g. alfuzosin), sildenafil (for treatment of pulmonary arterial HTN), irinotecan, and indinavir.
Special Precautions
Patient w/ haemophilia A/B, pre-existing cardiac conduction disorder (e.g. 1st-3rd degree AV or complex bundle branch block), DM, bradycardia, long congenital QT, electrolyte imbalance. Hepatic impairment (including chronic hepatitis B or C). Pregnancy.
Adverse Reactions
Jaundice, GI disturbance (e.g. abdominal pain, diarrhoea, nausea, vomiting, dyspepsia), headache, insomnia, peripheral neurological symptoms, ocular icterus, asthenia, fatigue; mild to moderate rash (e.g. maculopapular rash), cholelithiasis, nephrolithiasis; hyperbilirubinaemia, elevated amylase, lipase, and liver enzymes, low neutrophils; lipodystrophy (e.g. central obesity, dorsocervical fat enlargement, peripheral wasting, breast enlargement, cushingoid appearance); insulin resistance, hyperglycaemia, hyperlactataemia; elevated creatine phosphokinase, myalgia, myositis; osteonecrosis, Grave’s disease, immune reconstitution syndrome. Rarely, rhabdomyolysis.
Potentially Fatal: Stevens-Johnson syndrome, erythema multiforme, toxic skin eruptions, drug rash w/ eosinophilia and systemic symptoms (DRESS); PR interval prolongation. Rarely, QT prolongation, torsade de pointes.
MonitoringParameters
Perform LFTs before and during treatment. Monitor viral load, CD4, blood lipids and glucose, and bilirubin. Monitor ECG esp in patient w/ pre-existing prolonged PR interval.
Overdosage
Symptoms: Jaundice, hyperbilirubinaemia, asymptomatic bifascicular block, PR interval prolongation. Management: Supportive treatment. Induce emesis or employ gastric lavage; activated charcoal may also be given.
Drug Interactions
Decreased concentration w/ PPIs, efavirenz, nevirapine, and rifampicin. May increase serum concentration of inhaled fluticasone and salmeterol.
Potentially Fatal: Increased risk for myopathy (i.e. rhabdomyolysis) w/ simvastatin and lovastatin. Increased risk for cardiac arrhythmia w/ cisapride. May increase risk of hypotension w/ alfuzosin. May increase potential of serious AR of amiodarone, bepridil, quinidine, and systemic lidocaine. May increase serum concentration of astemizole, terfenadine, pimozide, quetiapine, dihydroergotamine, ergometrine, ergotamine, methylergometrine, triazolam, and oral midazolam. May increase risk for hypotension, visual changes, and priapism w/ sildenafil (when used for pulmonary arterial HTN). May inhibit UGT1A1 causing an increase toxicity of irinotecan. May cause indirect hyperbilirubinaemia w/ indinavir.
Food Interaction
Enhanced absorption w/ food. Decreased concentration w/ St John’s wort.
Action
Description: Atazanavir, a synthetic azapeptide, is a selective, competitive, and reversible HIV-1 protease inhibitor. It inhibits the cleavage of viral Gag and Gag-Pol polyprotein precursors into individual functional proteins, preventing the processing of the polyproteins into mature and infectious virions.
Pharmacokinetics:
Absorption: Rapidly absorbed from the GI tract. Enhanced absorption w/ food. Time to peak plasma concentration: Approx 2-2.5 hr.
Distribution: Distributed in the CSF and semen in low concentration. Plasma protein binding: 86%, w/ similar affinity to albumin and α1-acid glycoprotein.
Metabolism: Extensively metabolised in the liver by CYP3A4 enzyme, mainly via mono-oxygenation and deoxygenation into inactive metabolites; also undergoes glucuronidation, N-dealkylation, hydrolysis, and oxygenation w/ dehydrogenation into 2 minor inactive metabolites.
Excretion: Via faeces (79%, 20% as unchanged drug) and urine (13%, 7% as unchanged drug). Terminal elimination half-life: Approx 7 hr.
Chemical Structure

Chemical Structure Image
Atazanavir

Source: National Center for Biotechnology Information. PubChem Database. Atazanavir, CID=148192, https://pubchem.ncbi.nlm.nih.gov/compound/Atazanavir (accessed on Jan. 21, 2020)

Storage
Store between 15-30°C.
MIMS Class
ATC Classification
J05AE08 - atazanavir ; Belongs to the class of protease inhibitors. Used in the systemic treatment of viral infections.
References
Anon. Atazanavir. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 12/10/2016.

Buckingham R (ed). Atazanavir Sulfate. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 12/10/2016.

Joint Formulary Committee. Atazanavir. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 12/10/2016.

McEvoy GK, Snow EK, Miller J et al (eds). Atazanavir Sulfate. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 12/10/2016.

Reyataz Capsule, Gelatin Coated (A-S Medication Solutions). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 12/10/2016.

Disclaimer: This information is independently developed by MIMS based on Atazanavir from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
  • Reyataz
Register or sign in to continue
Asia's one-stop resource for medical news, clinical reference and education
Sign up for free
Already a member? Sign in