Ranitidine


Histamine H2 receptor antagonist used in the treatment of gastric and duodenal ulcers, gastroesophageal reflux and hypersecretory states.
 
Incidence
Uncommon.
 
3 cases described in obstetric patients.
 
Clinical manifestations
Differentiate from other side-effects: headaches, tiredness, dizziness, mild gastrointestinal disturbance.
 
General: anaphylactic shock
 
Respiratory: dyspnea, bronchospasm, laryngeal edema.
 
Cutaneous: pruritus, urticaria, edema of the face, tongue, arms, maculopapular rash, toxic epidermal necrolysis, cutaneous delayed reactions (papular eruptions).
 
Digestive: acute cholestatic hepatitis with rash and hypereosinophilia (one case).
 
Diagnostic methods
Cutaneous testing.
 
Skin prick-tests: 10 mg/ ml positive with ranitidine, negative with famotidine, nizatidine, nitrofurantoin.
 
Intradermal skin tests: one case positive 1/1000.
 
No specific IgE found.
 
Oral challenge.
 
Mechanisms
IgE-mediated hypersensitivity (positive skin tests, positive oral challenge).
 
Direct histamine release.
 
Management
Cross-reactivity with other H2 receptor antagonists is exceptional (one case published)
 
Omeprazole can be used in obstetric patients to reduce gastric acid production.

References

  1. Gonzalo-Garijo M.A, Revenga-Arranz F, Rovira-Farre I, "Cutaneous delayed reaction to ranitidine", Allergy., 1996; 51 (9): 659-60
  2. Lazaro M, Compaired J.A, de la Hoz B, Igea J.M, Marcos C, Davila I, Losada E, "Anaphylactic reaction to ranitidine", Allergy, 1993; 48 (5): 385-7
  3. Powell J.A, Maycock E.J, "Anaphylactoid reaction to ranitidine in an obstetric patient", Anaesth. Intensive. Care., 1993; 21 (5): 702-3
  4. Picardo M, Santucci B, "Urticaria from ranitidine", Contact. Dermatitis., 1983; 9: 327

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