Despite the widespread use of non-steroidal anti-inflammatory drugs (
NSAIDs), the current number of reported cases of
poisoning is small. However, with the introduction of 'over-the-counter' preparations of
NSAIDs in some countries (e.g.
ibuprofen in the UK and USA) an increased incidence of acute
poisoning from this group of drugs can be expected. Conventionally,
NSAIDs are divided into the following groups based on their chemical structure: arylpropionic
acids,
indole and
indene acetic acids, heteroarylacetic
acids,
fenamates,
phenylacetic acids,
pyrazolones and oxicams. Unless
NSAIDs are ingested in substantial overdose, acute
poisoning with these agents does not usually result in significant morbidity or mortality. In most cases the clinical features are mild and confined to the gastrointestinal and central nervous systems, though
acute renal failure, hepatic dysfunction,
respiratory depression,
coma, convulsions, cardiovascular collapse and
cardiac arrest may complicate severe
poisoning. Arylpropionic
acid derivatives were thought initially to have a low order of toxicity in overdose but, in addition to anticipated gastrointestinal symptoms,
headache,
tinnitus,
hyperventilation,
sinus tachycardia, hypoprothrombinaemia, haematuria,
proteinuria and
acute renal failure have been described. In addition, drowsiness,
coma, nystagmus,
diplopia,
hypothermia,
hypotension,
respiratory depression and
cardiac arrest have been reported in severe cases of
poisoning.
Oxyphenbutazone and
phenylbutazone are considerably more toxic in overdose. Complications of severe
poisoning include
coma, convulsions, hepatic dysfunction,
acute renal failure,
sodium and water retention, haematuria, cardiovascular collapse,
respiratory alkalosis,
metabolic acidosis, hypoprothrombinaemia and
thrombocytopenia. In contrast,
indomethacin appears to be much less toxic. In addition to gastrointestinal symptoms,
indomethacin taken in overdose induces
headache,
tinnitus,
dizziness,
lethargy, drowsiness,
confusion, disorientation and
restlessness. Only 1 case of acute
sulindac poisoning has been reported in the literature. A 16-year-old boy was admitted with hypokalaemia (2.2 mmol/L), transient granulocytosis and 'scanty' haematemesis after ingesting 12 g
sulindac. No case of acute
tolmetin poisoning have been reported. The
fenamates (
flufenamic acid,
meclofenamic acid,
mefenamic acid,
tolfenamic acid) are, with the exception of
mefenamic acid, not as widely prescribed as other groups of
NSAIDs. In overdose,
mefenamic acid may result in
nausea,
vomiting, diarrhoea, muscle twitching, convulsions and
coma.(ABSTRACT TRUNCATED AT 400 WORDS)