The skin is the organ most frequently affected by adverse drug reactions (ADRs). In 2003, dermatological ADRs accounted for 46% of all adverse reactions reported to the Pharmacovigilance (PV) Unit. Most of the reported dermatological ADRs were the non-serious types such as urticaria, erythema and rashes. However there were a significant number of serious and potentially life-threatening reactions such as and toxic epidermal necrolysis (TEN) and Stevens Johnson syndrome (SJS). Refer to Table 1 for descriptions of TEN and SJS.
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Analysis of local ADR reports
Between January 1997 and May 2004, the PV Unit has received 35 reports of TEN and 111 reports of SJS. The top ten suspected causative drugs are:
Carbamazepine (24 reports) Cotrimoxazole (21 reports)
Phenytoin (14 reports) Amoxicillin (12 reports)
Allopurinol (11 reports) Coamoxiclav (8 reports)
Ceftriaxone (6 reports) Mefenamic acid (5 reports)
Ciprofloxacin (4 reports) Cloxacillin (4 reports)
The other drugs implicated include the following:
Anti-infectives: Ampicillin, bacampicillin, cefadroxil, cefalexin, ceftazidime, cefuroxime, chloramphenicol, clindamycin, dapsone, doxycycline, erythromycin, imipenem/cilastatin, levofloxacin, lincomycin, methisoprinol, metronidazole, moxifloxacin, nitrofurantoin, ofloxacin, rifampicin, spiramycin, sulfadiazine, tetracycline and trimethoprim
Anti-inflammatory agents: Aspirin, celecoxib, diclofenac, etoricoxib, ibuprofen, isoniazid, mefenamic acid, nimesulide and piroxicam
Antiepileptics: Gabapentin, lamotrigine and phenobarbitone
Analgesics: Chlormezanone/paracetamol, codeine/promethazine, orphenadrine/ paracetamol and paracetamol
Cardiac drugs: Amlodipine, captopril, hydrochlorothiazide, losartan and perindopril
Others: Alendronate, amitriptyline, atropine/diphenoxylate, glucosamine, hydroxychloroquine, mesalazine, omeprazole, prochlorperazine, ticlopidine, tolbutamide, trichloroethylene and trifluoperazine
Further analysis of the data revealed that the patients' ages ranged from 1 to 89 years. More females were reported to suffer from these ADRs: 79 females compared to 59 males.
Table 1: Comparison of TEN and SJS
TEN | SJS | |
Estimated incidence | 0.4 – 1.2 cases per million population per year | 1.2 – 6 cases per million population per year |
Possible causes | 95% drug-induced | 1/3 cases are drug-induced, 15% due to infections |
Mortality | 44% (major cause: sepsis) | < 5% |
Description | · Fever (higher) · Influenza-like syndrome 1-3 days before development of lesions · Discrete red macules, lesions of the skin and mucous membranes of conjunctiva, oral cavity and/or genitalia · > 30% of epidermis involved · Pulmonary complications · Anaemia, lymphopenia, neutropenia · Mild elevations of liver enzymes | · Fever · Influenza-like syndrome 1-3 days before development of lesions · Discrete red macules, lesions of the skin and mucous membranes of conjunctiva, oral cavity and/or genitalia · < 10% of epidermis involved · May evolve into TEN |
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References
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