Issues Affecting ART Success: Adherence, ARV Toxicity, Drug Interactions

1. Issues Affecting ART Success: Adherence, ARV Toxicity, Drug Interactions Guidelines for the Use of Antiretroviral Agents in Adults and Adolescents December 2009 AETC NRC Slide Set

2. About This Presentation These slides were developed using the December 2009 guidelines. The intended audience is clinicians involved in the care of patients with HIV. Because the field of HIV care is rapidly changing, users are cautioned that the information in this presentation may become out of date quickly. It is intended that these slides be used as prepared, without changes in either content or attribution. Users are asked to honor this intent. – AETC NRC http://www.aidsetc.org www.aidsetc.org

3. Initiation of Therapy: Contents • Adherence • ARV-associated adverse effects • Drug interactions www.aidsetc.org

4. Adherence • High adherence rates associated with virologic suppression, low rates of resistance, and improved survival • Important to assess readiness for ART prior to initiating therapy, and to assess adherence at each clinic visit • Suboptimal adherence is common www.aidsetc.org

5. Predictors of Inadequate Adherence • Regimen complexity and pill burden • Low literacy level • Active drug use or alcoholism • Stigma • Mental illness (especially depression) • Cognitive impairment • Lack of patient education • Medication adverse effects • Treatment fatigue www.aidsetc.org

6. Predictors of Inadequate Adherence (2) • Age, race, sex, educational level, socioeconomic status, and a past history of alcoholism or drug use do NOT reliably predict suboptimal adherence • Higher socioeconomic status and education levels and lack of history of drug use do NOT reliably predict optimal adherence www.aidsetc.org

7. Measurement of Adherence • No gold standard • Patient self-report overestimates adherence, but is associated with viral load responses and is most useful method in the clinic setting • Self-report of suboptimal adherence is strong indicator of nonadherence www.aidsetc.org

8. Predictors of Good Adherence • Emotional and practical supports • Convenience of regimen • Understanding of the importance of adherence • Belief in efficacy of medications • Feeling comfortable taking medicationsin front of others • Keeping clinic appointments • Severity of symptoms or illness www.aidsetc.org

9. Improving Adherence • Establish readiness to start therapy • Provide education on medication dosing • Review potential side effects • Anticipate and treat side effects • Use educational aids including pictures, pillboxes, and calendars www.aidsetc.org

10. Improving Adherence (2) • Simplify regimens, dosing, and food requirements • Engage family, friends • Utilize team approach with nurses, pharmacists, and peer counselors • Provide accessible, trusting health careteam www.aidsetc.org

11. ART-Associated Adverse Effects • Lactic acidosis/hepatic steatosis • Hepatotoxicity • Insulin resistance, diabetes melitis • Fat maldistribution • Hyperlipidemia • Cardiovascular and cerebrovascular effects • Increased bleeding in hemophiliacs • Osteonecrosis, osteopenia, osteoporosis • Rash www.aidsetc.org

12. All NRTIs: Lactic acidosis and hepatic steatosis (highest incidence with d4T, then ddI and ZDV, lower with TDF, ABC, 3TC, and FTC) Lipodystrophy(higher incidence with d4T) Adverse Effects: NRTIs www.aidsetc.org

13. ABC HSR* Rash Possible ↑ risk of MI ddI GI intolerance Peripheral neuropathy Pancreatitis Possible noncirrhotic portal hypertension Adverse Effects: NRTIs (2) * Screen for HLA-B*5709 before treatment with ABC; ABC should not be given to patients who test positive for HLA-B*5709. www.aidsetc.org

14. Adverse Effects: NRTIs (3) • d4T • Peripheral neuropathy • Pancreatitis • TDF • Renal impairment • Possible decrease in bone mineral density • Headache • GI intolerance • ZDV • Headache • GI intolerance • Bone marrow suppression www.aidsetc.org

15. All NNRTIs: Rash, including Stevens-Johnson syndrome Drug-drug interactions EFV Neuropsychiatric Teratogenic in nonhuman primates + cases of neural tube defects in human infants after 1st-trimester exposure NVP Higher rate of rash Hepatotoxicity (may be severe and life-threatening;risk higher in patients with higher CD4 counts at the time they start NVP) Adverse Effects: NNRTIs www.aidsetc.org

16. All PIs: Hyperlipidemia Insulin resistance and diabetes Lipodystrophy Elevated LFTs Possible increased risk of MI and CVA Possibility of increased bleeding riskfor hemophiliacs Drug-drug interactions Adverse Effects: PIs www.aidsetc.org

17. ATV Hyperbilirubinemia PR prolongation Nephrolithiasis DRV Rash Liver toxicity FPV GI intolerance Rash Possible increased risk of MI Adverse Effects: PIs (2) www.aidsetc.org

18. IDV Nephrolithiasis GI intolerance LPV/r GI intolerance Possible increased risk of MI PR and QT prolongation NFV Diarrhea Adverse Effects: PIs (3) www.aidsetc.org

19. RTV GI intolerance Hepatitis SQV GI intolerance TPV GI intolerance Rash Hyperlipidemia Liver toxicity Cases of intracranial hemorrhage Adverse Effects: PIs (4) www.aidsetc.org

20. RAL Nausea Headache Diarrhea CPK elevation Adverse Effects: II www.aidsetc.org

21. Adverse Effects: Fusion Inhibitor • ENF • Injection-site reactions • HSR • Increased risk of bacterial pneumonia www.aidsetc.org

22. Adverse Effects: CCR5 Antagonist • MVC • Drug-drug interactions • Abdominal pain • Upper respiratory tract infections • Cough • Hepatotoxicity • Musculoskeletal symptoms • Rash • Orthostatic hypotension www.aidsetc.org

23. ARV-Associated Adverse Effects: Lactic Acidosis/Hepatic Steatosis • Rare, but high mortality • Evidently due to mitochondrial toxicity • Associated with NRTIs (especially d4T, ddI, ZDV) • More common in women, pregnancy, obesity • Clinical presentation variable: have high index of suspicion • Lactate >2-5 mmol/dL plus symptoms • Treatment: discontinue ARVs, supportive care www.aidsetc.org

24. ARV-Associated Adverse Effects: Hepatotoxicity • Severity variable: usually asymptomatic, may resolve without treatment interruption • May occur with any NNRTI or PI, most NRTIs, or MVC: • NVP: risk of severe hepatitis in first 18 weeks of use (monitor LFTs closely), increased risk in chronic hepatitis B and C, women, and high CD4 count at initiation of NVP (>250 cells/µL in women, >400 cells/µL in men) • PIs: especially RTV, TPV, perhaps DRV; increased risk in hepatitis B or C, ETOH, other hepatotoxins www.aidsetc.org

25. ARV-Associated Adverse Effects: Insulin Resistance, Diabetes • Insulin resistance, hyperglycemia, and diabetes associated with ZDV, d4T, some PIs, especially with chronic use • Mechanism not well understood • Insulin resistance, relative insulindeficiency • Screen regularly: fasting glucose www.aidsetc.org

26. Lipodystrophy: No uniform definition Mechanism not well understood Peripheral fat wasting more associated with NRTIs, especially thymidine analogues (d4T>ZDV, ddI>TDF, ABC, 3TC, FTC) Central fat accumulation perhaps more associated with PIs, especially if used with thymidine analogues May be associated with dyslipidemia, insulin resistance, lactic acidosis Monitor closely; intervene early Treatment: switching to other agents may slow or halt progression ARV-Associated Adverse Effects: Fat Maldistribution www.aidsetc.org

27. Elevations in total cholesterol, LDL, and triglycerides Elevation in HDL seen with some RTV-boosted PIs Associated with all PIs (except ATV), d4T, EFV, NVP Mechanism unknown Concern for cardiovascular events, pancreatitis Monitor regularly Treatment: consider ARV switch; lipid-lowering agents (caution with PI + certain statins) ARV-Associated Adverse Effects: Hyperlipidemia www.aidsetc.org

28. Increased risk of MI and CVA associated with PIs Increased risk of MI associated with recent ABC use in some studies (data are not consistent) Seen especially in patients with traditional cardiovascular risk factors Assess and manage cardiovascular risk factors Consider ARVs with less risk of cardiovascular events, especially in patients at high risk of cardiovascular disease ARV-Associated Adverse Effects: Cardiovascular and Cerebrovascular Effects www.aidsetc.org

29. Osteonecrosis (AVN) Mechanism unknown Associated with PIs; unclear whether caused by them Other risk factors: corticosteroid treatment, alcohol abuse, hemoglobinopathies, hyperlipidemia, hypercoagulable states Treatment: surgical treatment for severe disease Osteopenia Associated with various ARVs, particularly TDF, d4T Other risk factors: low body weight, female, white or Asian, older age, alcohol or tobacco use, hypogonadism, vitamin D deficiency, corticosteroid exposure Consider assessment by DEXA Management: calcium + vitamin D, bisphosphonate, weight-bearing exercise, hormone replacement ARV-Associated Adverse Effects: Bone Abnormalities www.aidsetc.org

30. ARV-Associated Adverse Effects: Rash • Most common with NNRTIs, especially NVP • Most cases mild to moderate, occurring in first 6 weeks of therapy; occasionally serious (eg, Stevens-Johnson syndrome) • No benefit of prophylactic steroids or antihistamines (increased risk with steroids) • NRTIs: especially ABC (consider hypersensitivity syndrome) • PIs: especially FPV, DRV, TPV • CCR5 antagonist: MVC www.aidsetc.org

31. ARV-Associated Adverse Effects: Nephrotoxicity • Associated with IDV, TDF • IDV: increased Cr, pyuria, hydronephrosis or renal atrophy • TDF: increased Cr, proteinuria, hypophosphatemia, hypokalemia, proteinuria • Increased risk in patients with renal disease, low CD4 count • Monitor Cr, other renal parameters • Management: stop the offending ARV + supportive care www.aidsetc.org

32. Overlapping Toxicities • Peripheral neuropathy • ddI, d4T, ddC, isoniazid • Bone marrow suppression • ZDV, dapsone, hydroxyurea, ribavirin, TMP-SMZ • Hepatotoxicity • NVP, EFV, MVC, NRTIs, PIs, macrolides, isoniazid • Pancreatitis • ddI, RTV, d4T, TMP-SMZ, pentamidine www.aidsetc.org

33. Drug Interactions with ARVs • Certain ARVs, particularly PIs and NNRTIs, have significant drug interactions with other ARVs and with other medications • Interactions may be complex and difficult to predict • Coadministration of some ARVs with other ARV or non-ARV medications may require dose adjustment, and some combinations may be contraindicated • Check for interactions before prescribing www.aidsetc.org

34. Drug Interactions with ARVs • Increases in serum drug levels caused by inhibitors of metabolism may increase risk of medication toxicity, while decreases in drug levels caused by inducers of metabolism may cause treatment failure • Some drug interactions may be exploited, eg, low-dose ritonavir (a strong CYP3A4 inhibitor) may be used as a pharmacokinetic enhancer to increase concentrations and prolong the half-life of other PIs www.aidsetc.org

35. Drug Interactions with ARVs • All PIs and NNRTIs are metabolized by the hepatic CYP 450 system, particularly the CYP3A4 • PIs • All PIs are CYP3A4 substrates, and their serum levels may be affected by CYP inducers or inhibitors • Some PIs also are inducers or inhibitors of other CYP isoenzymes or of P-glycoprotein (PGP) or other transporters • NNRTIs • Substrates of CYP3A4, can act as inducer (NVP) or mixed inducer and inhibitor (EFV) • ETR is substrate of 3A4, 2C9, and 2C19; and inhibitor of 2C9 and 2C19 www.aidsetc.org

36. Drug Interactions with ARVs • NRTIs • No hepatic metabolism, but some NRTIs may interact via other mechanisms (eg, decrease in ATV concentration if coadministered with TDF, proton pump inhibitors, H2 receptor antagonists) • Integrase inhibitor • RAL: eliminated by glucuronidation; inducers of UGT1A1 (eg, rifampin) can reduce RAL concentration www.aidsetc.org

37. Drug Interactions with ARVs • CCR5 antagonist • MVC: substrate of CYP3A and PGP; concentrations are significantly affected by CYP3A inhibitors or inducers. Dosage adjustment necessary. • Fusion inhibitor • ENF: no known significant drug interactions www.aidsetc.org

38. Common Drug Interactions with ARVs: Require Dosage Modification or Cautious Use • Lipid-lowering agents • Antimycobacterials, especially rifampin* • Antifungals • Psychotropics – midazolam, triazolam • Ergot alkaloids • Antihistamines – astemizole • Anticonvulsants * Of NNRTIs and PIs, rifampin may be used only with full-dose RTV or with EFV. www.aidsetc.org

39. Common Drug Interactions with ARVs: Require Dosage Modification or Cautious Use (2) • Oral contraceptives(may require second method) • Methadone • Erectile dysfunction agents • Herbs – St. John’s wort www.aidsetc.org

40. ARV-ARV Interactions: Require Dosage Modification or Cautious Use • EFV, NVP, or ETR with PIs • ATV + TDF • ddI + TDF • ddI + d4T • MVC + many PIs • MVC + EFV or ETR www.aidsetc.org

41. ARV-ARV Interactions • Interactions involving ARVs often require dose adjustment of the ARV and/or the interacting medication • Some combinations are contraindicated • Consider the possibility of interactions whenever adding a new medication • Consult with expert pharmacists or clinicians www.aidsetc.org

42. Websites to Access the Guidelines • http://www.aidsetc.org • http://aidsinfo.nih.gov www.aidsetc.org

43. About This Slide Set • This presentation was prepared by Susa Coffey, MD, for the AETC National Resource Center in December 2009. • See the AETC NRC website for the most current version of this presentation: http://www.aidsetc.org www.aidsetc.org