Opportunistic Infection Prophylaxis

Which prophylaxis the CD4 count calls for, and what to do about a sulfa allergy · v1.7
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  • Enter the CD4 band, the WHO clinical stage, and whether the patient is on ART and for how long.
  • Add the pregnancy status, any treated cryptococcal disease, the active TB status and any sulfonamide allergy.
  • You get the prophylaxis due, cotrimoxazole, TB preventive treatment and fluconazole, each with its start and stop rule.
  • The screening that comes first is printed with the course, and the four-symptom TB screen must be negative before preventive treatment starts.
  • The Evidence and Pearls tab holds the same five rules as one table, to read without entering anything.

  • Treatment of an established opportunistic infection. It gives prophylaxis only.
  • The choice of ART regimen, which the First-Line ART pathway decides.
  • Any dose scaled to weight or to age. The form asks for neither, and the doses printed are the adult ones.
  • Prophylaxis outside the NACO set, so azithromycin against Mycobacterium avium complex is not offered.
1. Current Disease Status
2. Prior OI History
OI Prophylaxis Quick Reference
ProphylaxisStart WhenDrug & DoseStop When
CotrimoxazoleCD4 < 350 or WHO Stage 3/4TMP-SMX 960mg (DS) ODCD4 > 350 on two readings 6 months apart, viral load suppressed
TPT: 1HP (preferred)All PLHIV aged 13 and above, after excluding active TBINH 300mg + Rifapentine 600mg daily x 28 days, with Pyridoxine 25mgAfter completing the 28-day course
TPT: 6HPregnant or breastfeeding, under 13 years, or on a protease inhibitorINH 300mg + Pyridoxine 25mg OD x 6 monthsAfter completing the 6-month course
FluconazoleAfter treated Cryptococcal disease200mg OD (secondary prophylaxis)CD4 > 200 for ≥ 6 months on ART
CrAg ScreeningCD4 < 100Serum CrAg lateral flow assayIf CrAg+: LP to exclude meningitis; pre-emptive Fluconazole
1. TPT: Key Safety Points
Symptom screen before TPT: Ask about cough > 2 weeks, fever, weight loss and night sweats, and if any one of the four is positive do GeneXpert before TPT is started. Otherwise you are giving INH alone against undiagnosed active TB, and resistance follows quickly.
INH hepatotoxicity: The risk rises with age > 35, with alcohol use, and with pre-existing liver disease. Monitor ALT at baseline, then monthly for the first 3 months. Stop if ALT > 3x ULN with symptoms, or > 5x ULN without.
Peripheral neuropathy: INH depletes pyridoxine (vitamin B6). Co-prescribe Pyridoxine 25mg OD from the start of the course, not once symptoms appear.
Abbreviations ACE (Angiotensin-Converting Enzyme) · ALT (Alanine Aminotransferase) · ARB (Angiotensin Receptor Blocker) · ART (Antiretroviral Therapy) · ATT (Anti-Tubercular Therapy) · CD4 (Cluster of Differentiation 4) · CPT (Cotrimoxazole Preventive Therapy) · CrAg (Cryptococcal Antigen) · CXR (Chest X-Ray) · CYP (Cytochrome P450) · DS (Double Strength) · ECG (Electrocardiogram) · ENaC (Epithelial Sodium Channel) · G6PD (Glucose-6-Phosphate Dehydrogenase) · GFR (Glomerular Filtration Rate) · HIV (Human Immunodeficiency Virus) · IgG (Immunoglobulin G) · INH (Isoniazid) · LFT (Liver Function Test) · LP (Lumbar Puncture) · NACO (National AIDS Control Organisation) · OD (Once Daily) · OI (Opportunistic Infection) · PCP (Pneumocystis jirovecii Pneumonia) · PLHIV (People Living with HIV) · QTc (Corrected QT Interval) · SBAR (Situation, Background, Assessment, Recommendation) · SJS (Stevens-Johnson Syndrome) · TB (Tuberculosis) · TEN (Toxic Epidermal Necrolysis) · TMP (Trimethoprim) · TMP-SMX (Trimethoprim-Sulfamethoxazole) · TPT (Tuberculosis Preventive Treatment) · ULN (Upper Limit of Normal) · WHO (World Health Organization) · 1HP (One Month of Daily Isoniazid and Rifapentine) · 6H (Six Months of Daily Isoniazid)
References
  1. NACO. National Guidelines for HIV Care and Treatment. MoHFW, GoI; 2021.
  2. NACO. Guidance on TB Preventive Treatment (TPT) for People Living with HIV. MoHFW, GoI; 20 May 2024.
  3. WHO. Consolidated guidelines on HIV prevention, testing, treatment, service delivery and monitoring: recommendations for a public health approach. Geneva: WHO; 2021.
  4. WHO. WHO consolidated guidelines on tuberculosis. Module 1: prevention. Tuberculosis preventive treatment. Geneva: WHO; 2020, with the 2024 update.
  5. Gupta A, Montepiedra G, Aaron L, et al. Isoniazid preventive therapy in HIV-infected pregnant and postpartum women. N Engl J Med. 2019;381(14):1333-1346.
  6. World Health Organization. WHO updated recommendations on HIV clinical management: recommendations for a public health approach. Geneva: WHO; 7 January 2026.
How to Cite This Tool

DOIhttps://doi.org/10.5281/zenodo.22401594

AMA Style:Umakanth S. Opportunistic Infection Prophylaxis. Version 1.7. MEDiscuss Clinical Decision Support System. Published 2026. Accessed . https://mediscuss.org/cdss/hiv-oi-prophylaxis. doi:10.5281/zenodo.22401594

Vancouver Style:Umakanth S. Opportunistic Infection Prophylaxis [Internet]. Version 1.7. MEDiscuss.org; 2026 [cited ]. Available from: https://mediscuss.org/cdss/hiv-oi-prophylaxis. doi:10.5281/zenodo.22401594

Disclaimer and scope
Disclaimer: This decision-support system is written for healthcare professionals. It does not substitute clinical judgment, and the treating physician retains absolute responsibility for every diagnostic, dosing and therapeutic decision. The algorithms are built on the evidence as it stands, and the evidence moves. Verify the output against your current institutional protocol, and against the patient in front of you.
© 2026 MEDiscuss.org. All rights reserved. Provided free of charge for clinical use. Unauthorised reproduction or redistribution is strictly prohibited.
Category Therapeutic & Management PathwaysPathway
Specialties Internal Medicine, Infectious Diseases, HIV Medicine

Written and maintained by

Dr Shashikiran Umakanth

Last revised 24 August 2026

How these tools are written and reviewed

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