Ethambutol


Ethambutol was widely used in the treatment of tuberculosis. Side effects other than ocular toxicity are rare.
 
Incidence
Cutaneous reactions: 0.5%.
 
Drug fever: 0.3%.
 
Clinical manifestations
General: fever.
 
Cutaneous: pruritus, maculoerythematous rash, toxic epidermal necrolysis, purpura.
 
Respiratory: dyspnea, pulmonary infiltrates.
 
Haematological: eosinophilia, neutropenia, thrombocytopenia.
 
Diagnostic methods
Drug re-challenge is usually positive in the cases of fever or maculopapular rash.
 
Mechanisms
Unknown.
 
Management
Desensitization if absolutely necessary: 0.1 mg; 0.5 mg; 1 mg; 2 mg; 4 mg; 8 mg ; 16 mg; 32 mg; 50 mg; 100 mg; 200 mg at 45 minutes intervals; then 400 mg 3H30 later; then 400 mg x 3 the next day.

References

  1. Wong P.C, Yew W.W, Wong C.F, Choi H.Y, "Ethambutol-induced pulmonary infiltrates with eosinophilia and skin involvement", Eur. Respir. J., 1995 ; 8 (5): 866-8
  2. Matz J, Borish L.C, Routes J.M, Rosenwasser L.J, "Oral desensitization to rifampin and ethambutol in mycobacterial disease", Am. J. Respir. Crit. Care Med., 1994 ; 149 (3.1): 815-7
  3. Wong C.F, Yew W.W, "Ethambutol-induced neutropenia and eosinophilia", Chest, 1994 ; 106: 1638-9
  4. Pegram P.S Jr, Mountz J.D, O’Bar P.R, "Ethambutol-induced toxic epidermal necrolysis", Arch. Intern. Med., 1981 ; 141 (12): 1677-8
  5. Kerremans A, Majoor C.L, Gribnau F.W, "Hypersensitivity to ethambutol", Tubercle., 1981 ; 62 (3): 215-7

As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.