Introduction - Uppsala Monitoring Centre

hypoglycaemia, hypokalaemia, thrombocytopenia, increased INR/PTR 168 ,
intravascular coagulation, renal failure and non-cardiac pulmonary oedema.
Central nervous system features including confusion, disorientation, coma and
convulsions are less common in adults than in children.
British National Formulary (BNF)
Gastro-intestinal irritation with slight asymptomatic blood loss, increased bleeding
time, bronchospasm and skin reactions in hypersensitive patients. The chief
features of salicylate poisoning are hyperventilation, tinnitus, deafness,
vasodilatation, and sweating. Coma is uncommon but indicates very severe
poisoning. The associated acid-base disturbances are complex. Bearing in mind the
BNF and SPC are both intended to supply the prescriber with sufficient information,
the difference between them is large. One of the possible reasons for this is size;
the SPC is a very large volume which is rather too big to fit comfortably on a desk,
whilst the BNF is pocket size.
Comments
The long list of AEs is partly due to listing symptoms that are part of syndromes or
diseases, and are to that extent duplicated.
The number of ADRs caused when used for short periods at the recommended
dose are few and many of the ADRs mentioned are due to chronic use in diseases
such as rheumatoid arthritis when it is used at maximum (in)tolerable dosage or are
occasioned by accidental and deliberate overdosage.
A few AEs are either specific to salicylic acid/sodium salicylate, e.g. repulsive
taste or are probably not ADRs, e.g. strabismus.
Many of the AEs are part of common physio-pathological processes and
therefore unlikely to occur singly.
Many of the AEs mentioned under Aspirin precursors are also ADRs of Aspirin.
Common ADRs tend to be discovered in the first few years whilst the rare serious
events were discovered late in the history of Aspirin. Even ADRs, which are very
familiar, are surprisingly rare, e.g. gross haemorrhage–absolute risk increase 0.6%
(0.2%–1.0%); proven ulcer 0.06% (0%–1.2%) (Gøtzsche, 2000). For rare ADRs
such as agranulocytosis and aplastic anaemia the rate ratio estimates were for
salicylates 1.6 (1.0–2.7) and 1.0 (0.6–1.6) respectively. The authors said of the
agranulocytosis result that the statistical significance was borderline and it must be
interpreted with caution and of aplastic anaemia results that the rate ratio was
somewhat elevated but that the result could have been due to chance (IAAAS,
1986).
As Owen Wade pointed out it is strange that the recognition of the relationship
between the consumption of Aspirin or other salicylates and massive
gastrointestinal bleeding didn’t come until the late 1930s and 1940s (Wade, 1970).