Codeine (methylmorphine, morphine monomethyl ether) belongs to the opiod group. The main indication of codeine is as a cough suppressant.
Very low.
Risk factors
Intravenous use in children.
Clinical manifestations
General: arterial hypotension (intravenous route), pseudoscarlet fever.
Cutaneous: pruritus, urticaria, macular and maculopapular eruptions, angioedema, erythema multiforme, erythema nodosum, scarlatiniform rashes, fixed drug eruption (occupational dermatitis from codeine has been reported).
Respiratory: bronchospasm.
Diagnostic methods
Cutaneous testing
Skin patch-tests:codeine phosphate 0.1% aq. (fixed drug eruption).

codeine phosphate 0.001% to 0.033% aq. (urticarial rash).

Oral challenge tests (fixed drug eruption).
Non immunological histamine release (pruritus, urticaria).
Delayed-type hypersensitivity (urticaria, rash).
Vasomotor depression, ganglionar blockade and histamine release could explain hypotension.
Avoid intravenous use in children.
The risk of cross-sensitivity is higher with morphine congeners than with phenylpiperidine or methadone-type agents.


  1. Gonzalo-Garijo M.A, Revenga-Arranz F, "Fixed drug eruption due to codeine (letter)", Br.J.Dermatol., 1996 ; 135 (3): 498-9
  2. Rodriguez F, Fernandez L, Garcia-Abujeta J.L, Maquiera E, Llaca H.F, Jerez J, "Generalized dermatitis due to codeine", Contact. Dermatitis. , 1995 ; 32 (2): 120
  3. de Groot A.C, Conemans J, "Allergic urticarial rash from oral codeine", Contact. Dermatitis., 1986 ; 14 (4): 209-14.
  4. Shanahan E.C, Marshall A.G, Garrett C.P.O, "Adverse reactions to intravenous codeine phosphate in children. A report of 3 cases", Anaesthesia, 1983 ; 38 (1): 40-3.

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