Primary prophylaxis

Start primary prophylaxis for Pneumocystis jirovecii pneumonia (PJP) when the patient’s CD4 count is less than 200 cells/microlitre, or if CD4 cell percentage less than 14%.

Trimethoprim+sulfamethoxazole is the most effective prophylaxis against PJP and is recommended unless contraindicated (eg in patients hypersensitive to trimethoprim+sulfamethoxazole). If the patient also requires prophylaxis against Toxoplasma gondii infection, use the primary prophylaxis regimens for T. gondii encephalitis.

Note: Trimethoprim+sulfamethoxazole is the most effective prophylaxis against PJP.

The choice of trimethoprim+sulfamethoxazole regimen for primary PJP prophylaxis depends on patient preference, adherence and tolerability. Use:

1 trimethoprim+sulfamethoxazole 80+400 mg orally, daily; see below for advice on duration of therapy. For dosage adjustment in adults with kidney impairment, see trimethoprim+sulfamethoxazole PJP prophylaxis dosage adjustment pneumonia, PJP: primary prophylaxis (adult with HIV) trimethoprim + sulfamethoxazole

OR

1 trimethoprim+sulfamethoxazole 160+800 mg orally, daily; see below for advice on duration of therapy trimethoprim + sulfamethoxazole . For dosage adjustment in adults with kidney impairment, see trimethoprim+sulfamethoxazole PJP prophylaxis dosage adjustment

OR

2 trimethoprim+sulfamethoxazole 160+800 mg orally, 3 times weekly; see below for advice on duration of therapy¹. For dosage adjustment in adults with kidney impairment, see trimethoprim+sulfamethoxazole PJP prophylaxis dosage adjustment. trimethoprim + sulfamethoxazole

Assess patients reporting hypersensitivity to trimethoprim+sulfamethoxazole. Desensitisation (see Principles of antimicrobial desensitisation) is an option for clinically stable patients; however, do not desensitise patients with severe hypersensitivity (eg drug rash with eosinophilia and systemic symptoms [DRESS], Stevens–Johnson syndrome / toxic epidermal necrolysis [SJS/TEN]) or if adherence to therapy is unlikely. If 1 day of therapy is missed, the patient’s hypersensitivity will return and desensitisation must be performed again. Seek expert advice if desensitisation is being considered. If desensitisation is not an option, alternative regimens are provided below.

Note: Assess patients reporting hypersensitivity to trimethoprim+sulfamethoxazole.

For patients with nonsevere hypersensitivity to trimethoprim+sulfamethoxazole, use:

1 dapsone 100 mg orally, daily; see below for advice on duration of therapy² ³ ⁴. For dosage adjustment in adults with kidney impairment, see dapsone dosage adjustment pneumonia, PJP: primary prophylaxis (adult with HIV) dapsone

OR

2 pentamidine 300 mg via nebuliser, every 4 weeks; see below for advice on duration of therapy⁵ ⁶ pneumonia, PJP: primary prophylaxis (adult with HIV) pentamidine

OR

3 atovaquone 1500 mg orally with fatty food or full-fat milk, daily; see below for advice on duration of therapy. pneumonia, PJP: primary prophylaxis (adult with HIV) atovaquone

For patients with severe hypersensitivity to trimethoprim+sulfamethoxazole (eg anaphylaxis, DRESS, SJS/TEN), use pentamidine or atovaquone (see dosages above). Do not give dapsone because there is a possibility of cross-reactivity between dapsone and sulfamethoxazole (see Cross-reactivity between sulfonamides).

Duration of therapy: for patients taking combination antiretroviral therapy with a suppressed HIV viral load, stop primary prophylaxis when the CD4 count is more than 200 cells/microlitre for 3 months.

¹ Do not use the 3-times weekly regimen if the patient has undergone desensitisation for trimethoprim+sulfamethoxazole hypersensitivity.Return

² Test for glucose-6-phosphate dehydrogenase (G6PD) deficiency before starting treatment with dapsone—seek expert advice if the patient is G6PD deficient.Return

³ The cross-reactivity rate between dapsone and sulfamethoxazole is approximately 9 to 12%; do not use dapsone in patients with severe hypersensitivity (eg drug rash with eosinophilia and systemic symptoms [DRESS], Stevens–Johnson syndrome / toxic epidermal necrolysis [SJS/TEN]; see Types of antimicrobial hypersensitivity). Return

⁴ Reduce dapsone dosage to 50 mg daily in patients who develop toxicity (methaemoglobinaemia, chemical haemolysis).Return

⁵ Administer pentamidine via a jet nebuliser producing a droplet size of 1 to 2 microns.Return

⁶ Use with caution in patients with lung disease (eg asthma, COPD) because nebulised pentamidine may cause cough and bronchospasm.Return