Paracetamol, asthma association

Respiratory More evidence has been published on the topic of paracetamol use and asthma. In a prospective birth cohort study of 620 children with a first-degree family history of allergic disease, who were followed until age 7 years, the use of paracetamol was associated (with borderhne significance) with a risk of childhood asthma, but the association became clearly non-significant after adjustment for the frequency of respiratory infections [17 ]. There was no association between the use of paracetamol for non-respiratory causes and asthma. 

Aspirin-induced asthma has an onset of 30 minutes to 3 hours after ingestion. Affected individuals are cross-sensitive to all non-steroidal anti-inflammatory drugs (NSAIDs). Paracetamol is seldom associated with cross-sensitivity in patients with aspirin-induced asthma. Aspirin-induced asthma is believed to involve inhibition of COX-1. Patients should be provided with information on which drugs these are. 

An observational study, part of a population-based case-control study of dietary antioxidants and asthma, has shown an association between the regular use of paracetamol and the incidence of asthma and rhinitis in adults (10). After controlling for potential confounding factors the OR for asthma in daily users, compared with never users, was 2.38 (Cl = 1.22,4.64). Not unexpectedly, there was also an association in users and non-users of aspirin, strongest when cases with more severe disease were compared with controls. This adverse effect of paracetamol may be due to depletion of the antioxidant glutathione in the lungs. However, further studies are needed before paracetamol can be blamed for an increase in the prevalence and severity of asthma. 

Parvolex ) is used a MUCOLYTIC agent, which reduces the viscosity of sputum, so can be used as an expectorant in patients with disorders of the upper respiratory airways, such as chronic asthma and bronchitis. It is also used orally to treat abdominal complications associated with cystic fibrosis, and locally in the eye to increase lacrimation and mucus secretion. It is also used intravenously as an antidote in paracetamol poisoning. 

The effect of reduction in antioxidant activity has been explored in another way, by exposure to paracetamol, which depletes the antioxidant glutathione. In adults in Britain there was a positive relationship between paracetamol use and asthma [89(111)]. Paracetamol sales per capita have been examined in relationship to ISAAC data in 36 countries, and European Community Respiratory Health Survey data in 18 countries. There were positive correlations between paracetamol sales and symptoms of wheeze, rhinoconjunctivitis and eczema. An increase in paracetamol sales of lOg/capita was associated with an increase of 5.2% in asthma symptoms in 13- to 14-year-olds and 2.6% in adults [90(111)1. 

Asthmatic attacks due to non-narcotic analgesics, mostly occur in patients with so-called intrinsic or idiosyncratic asthma (often associated with nasal polyposis, sinusitis and eosinophilia of the blood) (McFadden and Austen 1977). About 10% of patients with this kind of asthma show severe reactions to aspirin, methyl-salicylate, pyrazolone derivatives, indomethacin, ibuprofen, diclofenac and sometimes even phenacetin and paracetamol. (Sodium salicylate is often tolerated.) The special reactivity may appear only in later life and concerns a number of chemically unrelated drugs. In some of these patients analgesic therapy with a morphine derivative such as pentazocine (Fortalgesic) or hyoscine butylbromide (Buscopan) may be necessary. However, in other patients, those with aspirin urticaria rather than asthma, the reaction may also rely on a drug-specific allergic mechanism (de Weck 1971). 

Respiratory More evidence has been published about the possible association between paracetamol and asthma. In a multicenter case-control study of 521 patients with asthma and 507 controls, weekly use of paracetamol, compared with less frequent use, was associated with asthma [25 ]. A study of 19 349 adult twins ermoUed in the nationwide Danish Twin Registry showed a higher prevalence of asthma in subjects with frequent intake of paracetamol (OR = 2.16 95% C3 = 1.03, 4.53) after adjusting for confounders [26 "]. Furthermore, a study of 205 487 children aged 6-7 years showed that paracetamol use for fever in the first year of life was associated with a higher risk of asthma... 

Beasley R, Clayton T, Crane J, von Mutius E, Lai CK, Montefort S, Stewart A. ISAAC Phase Three Study Group. Association between paracetamol use in infancy and childhood, and risk of asthma, rhinoconjunctivitis, and eczema in children aged 6-7 years analysis from Phase... 

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