Treatment algorithm

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

children ≥8 years of age and non-pregnant adults

1st line – tetracycline ± oxygen

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ACUTE
|
children ≥8 years of age and non-pregnant adults
1st line – 

tetracycline ± oxygen

Tetracyclines are the treatment of choice.[13]

Oral therapy is indicated in mild-to-moderate disease. Intravenous therapy is required in patients who are severely ill (i.e., with signs of pulmonary disease with diffuse involvement and fever, sepsis, disseminated intravascular coagulation, or findings consistent with other organ involvement such as the spleen or liver). A response is usually seen within 24 to 48 hours.

Treatment course is variable; however, 2 to 3 weeks is usually sufficient to prevent relapse. Longer courses of up to 6 weeks may be required in some patients, particularly those with severe illness.

Patients with severe pneumonitis require oxygen therapy.

Primary options

doxycycline: children: 2.2 mg/kg orally twice daily on day 1, followed by 2.2 mg/kg once or twice daily; or 4.4 mg/kg intravenously on day 1, followed by 2.2 mg/kg once or twice daily; adults: 100 mg orally twice daily on day 1, followed by 100 mg once or twice daily; or 200 mg intravenously on day 1, followed by 100 mg once or twice daily

OR

tetracycline: children: 25-50 mg/kg/day orally given in 4 divided doses; adults: 250-500 mg orally four times daily

2nd line – macrolide or fluoroquinolone ± oxygen

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ACUTE
|
children ≥8 years of age and non-pregnant adults
2nd line – 

macrolide or fluoroquinolone ± oxygen

Macrolides (e.g., erythromycin, azithromycin) and fluoroquinolones (e.g., moxifloxacin) are considered alternative second-line options when tetracyclines are contraindicated. Erythromycin is the best alternative, although it may be less efficacious than tetracyclines in severe illness, and treatment courses of up to 6 weeks may be required. Azithromycin may also be used, although there are reports of resistance.[29]

Oral therapy is indicated in mild-to-moderate disease. Intravenous therapy is required in patients who are severely ill (i.e., with signs of pulmonary disease with diffuse involvement and fever, sepsis, disseminated intravascular coagulation, or findings consistent with other organ involvement such as the spleen or liver). A response is usually seen within 24 to 48 hours.

Treatment course is variable; however, 2 to 3 weeks is usually sufficient to prevent relapse. Longer courses of up to 6 weeks may be required in some patients, particularly those with severe illness.

Patients with severe pneumonitis require oxygen therapy.

Primary options

erythromycin base: children: 50 mg/kg/day orally given in 2-4 divided doses, maximum 2000 mg/day; adults: 500 mg orally every 6 hours

OR

erythromycin lactobionate: children: 50 mg/kg/day intravenously given in divided doses every 6 hours, maximum 4000 mg/day; adults: 500-1000 mg intravenously every 6 hours, maximum 4000 mg/day

Secondary options

azithromycin: children: 10 mg/kg orally once daily on day 1, followed by 5 mg/kg once daily; adults: 500 mg orally/intravenously once daily on day 1, followed by 250 mg once daily

Tertiary options

moxifloxacin: adults: 400 mg orally/intravenously every 24 hours

3rd line – chloramphenicol or rifampicin ± oxygen

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ACUTE
|
children ≥8 years of age and non-pregnant adults
3rd line – 

chloramphenicol or rifampicin ± oxygen

Third-line treatment options include chloramphenicol and rifampicin, although there are many drug-drug interactions that limit the use of rifampicin.

Oral therapy is indicated in mild-to-moderate disease. Intravenous therapy is required in patients who are severely ill (i.e., with signs of pulmonary disease with diffuse involvement and fever, sepsis, disseminated intravascular coagulation, or findings consistent with other organ involvement such as the spleen or liver). A response is usually seen within 24 to 48 hours.

Treatment course is variable; however, 2 to 3 weeks is usually sufficient to prevent relapse. Longer courses of up to 6 weeks may be required in some patients, particularly those with severe illness.

Patients with severe pneumonitis require oxygen therapy..

Primary options

chloramphenicol: children and adults: 50-100 mg/kg/day intravenously given in divided doses every 6 hours, maximum 4000 mg/day

OR

rifampicin: children: 10 mg/kg/day orally/intravenously given in divided doses every 12 hours, maximum 600 mg/day; adults: 600 mg orally/intravenously every 12-24 hours

Plus – topical ophthalmic erythromycin

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ACUTE
|
children ≥8 years of age and non-pregnant adults
|
with conjunctivitis
Plus – 

topical ophthalmic erythromycin

Treatment recommended for ALL patients in selected patient group

Topical erythromycin is recommended for Chlamydia psittaci conjunctivitis.[3]

Primary options

erythromycin topical: (0.5%) apply to the lower conjunctiva twice daily

children <8 years and pregnant women

1st line – macrolide ± oxygen

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ACUTE
|
children <8 years and pregnant women
1st line – 

macrolide ± oxygen

Erythromycin is the treatment of choice in children. Azithromycin may be used as an alternative. Macrolides are also the preferred option in pregnant women.

Oral therapy is indicated in mild-to-moderate disease. Intravenous therapy is required in patients who are severely ill (i.e., with signs of pulmonary disease with diffuse involvement and fever, sepsis, disseminated intravascular coagulation, or findings consistent with other organ involvement such as the spleen or liver). A response is usually seen within 24 to 48 hours.

Treatment course is variable; however, 2 to 3 weeks is usually sufficient to prevent relapse. Longer courses of up to 6 weeks may be required in some patients, particularly those with severe illness.

Patients with severe pneumonitis require oxygen therapy.

Primary options

erythromycin base: children: 50 mg/kg/day orally given in 2-4 divided doses, maximum 2000 mg/day; adults: 500 mg orally every 6 hours

OR

erythromycin lactobionate: children: 50 mg/kg/day intravenously given in divided doses every 6 hours, maximum 4000 mg/day; adults: 500-1000 mg intravenously every 6 hours, maximum 4000 mg/day

Secondary options

azithromycin: children >6 months of age: 10 mg/kg orally once daily on day 1, followed by 5 mg/kg once daily; adults: 500 mg orally/intravenously once daily on day 1, followed by 250 mg once daily

2nd line – chloramphenicol or tetracycline ± oxygen

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ACUTE
|
children <8 years and pregnant women
2nd line – 

chloramphenicol or tetracycline ± oxygen

Chloramphenicol is a suitable second-line option; however, extreme caution should be used in children and pregnant women.

Gray syndrome (also known as gray baby syndrome), a type of circulatory collapse which is potentially life-threatening, has been reported in premature and newborn infants receiving chloramphenicol, and more rarely in children up to 2 years of age.

There is a lack of data to support the safety of chloramphenicol in pregnant women, and it should only be used if the benefits to the mother outweigh the risks to the fetus. It should not be used near term or during labour due to the risk of gray syndrome and bone marrow suppression in the neonate. Extreme caution is also recommended in breastfeeding women.

Tetracycline is not recommended due to detrimental effects on the skeletal development of the fetus but can be given in extreme cases as a life saving measure if erythromycin is ineffective.[36][37] The use of doxycycline has been described in a case report.[38]

It is generally recommended that tetracyclines are not used in children <8 years of age (<12 years of age in some countries such as the UK) due to the risk of tooth discolouration; however, they may be used in younger children if the benefits outweigh the risks, especially in life-threatening situations where other therapies are not effective.[13]

Treatment course is variable; however, 2 to 3 weeks is usually sufficient to prevent relapse. Longer courses of up to 6 weeks may be required in some patients, particularly those with severe illness.

Patients with severe pneumonitis require oxygen therapy.

Primary options

chloramphenicol: children and adults: 25-100 mg/kg/day intravenously given in divided doses every 6 hours, maximum 4000 mg/day

More

OR

tetracycline: children: 25-50 mg/kg/day orally given in 4 divided doses; adults: 250-500 mg orally four times daily

Plus – topical ophthalmic erythromycin

Back
ACUTE
|
children <8 years and pregnant women
|
with conjunctivitis
Plus – 

topical ophthalmic erythromycin

Treatment recommended for ALL patients in selected patient group

Topical erythromycin is recommended for Chlamydia psittaci conjunctivitis.[3]

Primary options

erythromycin topical: (0.5%) apply to the lower conjunctiva twice daily

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Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer

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