eMedicine Specialties > Infectious Diseases > Lower Respiratory Tract Infections
Psittacosis: Treatment & Medication
Updated: Jun 27, 2008
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
Treatment
Medical Care
Consider the diagnosis of psittacosis in patients with community-acquired pneumonia who have been exposed to birds. The mainstay of medical care is antibiotic therapy.
Consultations
- Notify public health authorities about cases of psittacosis.
- Obtain a consultation with an infectious disease specialist.
Diet
Patients require no specific diet.
Activity
Patients do not require activity restrictions.
Medication
The goals of pharmacotherapy are to reduce morbidity and to prevent complications.
Antibiotics
Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the clinical setting. Tetracycline and doxycycline are the antibiotics of choice. Treating patients for 2-3 weeks usually prevents relapse. Clinical response occurs within 24-72 hours. Use erythromycin in children younger than 9 years and in pregnant women. Chloramphenicol is a third alternative antibiotic.
Doxycycline remains the drug of choice. Macrolide and quinolone failures have been observed.
Azithromycin (Zithromax)
Anecdotal reports suggest that it is effective. Acts by binding to 50S ribosomal subunit of susceptible microorganisms and blocks dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. Nucleic acid synthesis is not affected.
Concentrates in phagocytes and fibroblasts as demonstrated by in vitro incubation techniques. In vivo studies suggest that concentration in phagocytes may contribute to drug distribution to inflamed tissues.
Treats mild-to-moderate microbial infections.
Plasma concentrations are very low, but tissue concentrations are much higher, giving it value in treating intracellular organisms. Has a long tissue half-life.
Adult
Day 1: 500 mg PO
Days 2-5: 250 mg PO qd
Community-acquired pneumonia: 500 mg PO/IV qd for 7-10 d
Pediatric
<6 months: Not established
>6 months:
Day 1: 10 mg/kg PO once; not to exceed 500 mg/d
Days 2-5: 5 mg/kg PO qd; not to exceed 250 mg/d
May increase toxicity of theophylline, warfarin, and digoxin; effects are reduced with coadministration of aluminum and/or magnesium antacids; nephrotoxicity and neurotoxicity may occur when coadministered with cyclosporine
Documented hypersensitivity; hepatic impairment; do not administer with pimozide
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Site reactions can occur with IV route; bacterial or fungal overgrowth may result from prolonged antibiotic use; may increase hepatic enzymes and cholestatic jaundice; caution in patients with impaired hepatic function or prolonged QT intervals
Doxycycline (Vibramycin)
DOC; inhibits protein synthesis and thus bacterial growth by binding to 30S and possibly 50S ribosomal subunits of susceptible bacteria. Continue treatment for at least 2 wk to prevent relapse.
Adult
100 mg PO bid
Severe cases: 4.4 mg/kg IV q12h
Pediatric
<8 years: not recommended
>8 years and <100 lb: 2 mg/kg/d in PO/IV in 1-2 divided doses on day 1; then 1-2 mg/kg/d in 1-2 divided doses; not to exceed 200 mg/d
>8 years and >100 lb: Administer as in adults
Bioavailability decreases slightly with antacids containing aluminum, calcium, magnesium, iron, or bismuth subsalicylate
Documented hypersensitivity
Pregnancy
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions
Photosensitivity is very rare with prolonged exposure to sunlight; avoid during last half of pregnancy through 8 y
Erythromycin (E-Mycin, Ery-Tab, E.E.S.)
Macrolide antibiotic; second DOC. Inhibits bacterial growth, possibly by blocking dissociation of peptidyl t-RNA from ribosomes, causing RNA-dependent protein synthesis to arrest. For treatment of staphylococcal and streptococcal infections. In children, age, weight, and severity of infection determine proper dosage. When bid dosing is desired, administer half total daily dose q12h. For more severe infections, double the dose.
Adult
500 mg erythromycin stearate/base (or 800 mg ethylsuccinate) PO qid 1 h ac for 2-3 wk
Alternatively, use 333 mg q8h; increase up to 4 g/d, depending on severity of infection
Pediatric
30-50 mg/kg/d (15-25 mg/lb/d) PO divided q6-8h; double dose for severe infection
Coadministration may increase toxicity of theophylline, digoxin, carbamazepine, and cyclosporine; may potentiate anticoagulant effects of warfarin; coadministration with lovastatin and simvastatin increases risk of rhabdomyolysis
Documented hypersensitivity; hepatic impairment
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Caution in liver disease; estolate formulation may cause cholestatic jaundice; GI adverse effects are common (administer doses pc); discontinue use if nausea, vomiting, malaise, abdominal colic, or fever occur
Chloramphenicol (Chloromycetin)
Third DOC but rarely used in the US. Binds to 50S bacterial-ribosomal subunits and inhibits bacterial growth by inhibiting protein synthesis. Effective against gram-negative and gram-positive bacteria.
Adult
500 mg IV qid for 2-3 wk
Pediatric
50-100 mg/kg/d IV divided q6h for 2-3 wk
Concurrently with barbiturates, chloramphenicol serum levels may decrease while barbiturate levels may increase and cause toxicity; manifestations of hypoglycemia may occur with sulfonylureas; rifampin may reduce serum chloramphenicol levels, presumably through hepatic enzyme induction; may increase effects of anticoagulants; may increase serum hydantoin levels, possibly resulting in toxicity; chloramphenicol levels may be increased or decreased
Documented hypersensitivity
Pregnancy
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions
Use only for indicated infections, or as prophylaxis for bacterial infections; serious and fatal blood dyscrasias (ie, aplastic anemia, hypoplastic anemia, thrombocytopenia, granulocytopenia) can occur; evaluate baseline and perform periodic blood studies approximately every 2 d while in therapy; discontinue upon appearance of reticulocytopenia, leukopenia, thrombocytopenia, anemia, or findings attributable to chloramphenicol; adjust dose in liver or kidney dysfunction; caution in pregnancy at term or during labor because of potential toxic effects on fetus (ie, gray syndrome)
Moxifloxacin (Avelox)
Inhibits the A subunits of DNA gyrase, resulting in inhibition of bacterial DNA replication and transcription. Anecdotal reports suggest that this drug is effective.
Adult
400 mg PO/IV qd
Pediatric
<18 years: Not recommended
>18 years: Administer as in adults
Antacids and electrolyte supplements reduce absorption; loop diuretics, probenecid, and cimetidine increase serum levels; NSAIDs enhance CNS stimulating effect
May increase toxicity of theophylline, caffeine, cyclosporine, and digoxin (monitor digoxin levels); may increase effects of anticoagulants (monitor PT); ferrous sulfate decreases bioavailability (administer moxifloxacin 4 h prior or 8 h following ferrous sulfate); coadministration with drugs that prolong QTc interval (quinidine, procainamide, amiodarone, sotalol, erythromycin, tricyclic antidepressants) increase risk of life-threatening arrhythmia
Documented hypersensitivity; known QT prolongation, concurrent administration of drugs that cause QT prolongation
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
In prolonged therapy, perform periodic evaluations of organ system functions (eg, renal, hepatic, hematopoietic); superinfections may occur with prolonged or repeated antibiotic therapy; fluoroquinolones have induced seizures in CNS disorders and caused tendinitis or tendon rupture
More on Psittacosis |
| Overview: Psittacosis |
| Differential Diagnoses & Workup: Psittacosis |
 Treatment & Medication: Psittacosis |
| Follow-up: Psittacosis |
| References |
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References
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Further Reading
Keywords
psittacosis, ornithosis, parrot fever, Chlamydia psittaci, C psittaci, avian-acquired psittacosis
