The chewing of betel nuts may worsen symptoms of asthma
A study of a possible interaction with betel nuts was prompted by observation of two Bangladeshi patients with severe asthma that appeared to have been considerably worsened by chewing betel nuts. One out of 4 other asthmatic patients who regularly chewed betel nuts developed severe bronchoconstriction (a 30 % fall in FEV1) on two occasions when given betel nuts to chew,and all 4 patients said that prolonged betel nut chewing induced coughing and wheezing. A double-blind study found that inhalation of arecoline (the major constituent of nut) caused bronchoconstriction in 6 of 7 asthmatics, and 1 of 6 healthy control subjects (See reference number 1). A study in asthmatic patients who regularly chewed betel nuts found that 4 patients had a mean increase in their FEV1 of 10 to 25%,whereas 11 patients had significant falls in their FEV1 of 11 to 25%. Interestingly, 5 of patients who did not think chewing betel nut affected their asthma experienced a reduction in their FEV1 (See reference number 2).
A survey in 61 asthmatic patients found that 22 of 34 patients who still chewed betel nut, either for occasional use or regularly, reported that it worsened their asthma (See reference number 3).
Betel nut quids consist of areca nut (Areca catechu) wrapped in betel vine leaf (Piper betle) and smeared with a paste of burnt (slaked) lime. It is chewed for euphoric effects of major constituent, arecoline, a cholinergic alkaloid, which appears to be absorbed through mucous membrane of mouth. Arecoline has identical properties to pilocarpine and normally has only mild systemic cholinergic properties; however asthmatic subjects seem to be particularly sensitive to bronchoconstrictor effects of this alkaloid and possibly other substances contained in nut.
Direct evidence appears to be limited to above reports, but interaction seems to be established. It would not normally appear to be a serious interaction,but asthmatics should be encouraged to avoid betel nuts. This is a drug-disease interaction rather than a drug-drug interaction.
Taylor RFH,Al-Jarad N, John LME, Conroy DM, Barnes NC. Betel-nut chewing and asthma.Lancet (1992) 339, 1134–6.
Sekkadde Kiyingi K,Saweri A. Betel nut chewing causes bronchoconstriction in some asthmapatients. P N G Med J (1994) 37, 90–9.
Kiyingi KS. Betel-nut chewing may aggravate asthma. P N G Med J (1991) 34,117–21.