Other medications and asthma

Antibiotics

• Antibiotics should be reserved for specific infections and are therefore rarely indicated in the treatment of asthma exacerbations.
• Mucus hypersecretion and a productive cough are a frequent manifestation of asthma. Discoloured sputum may be due to allergic inflammation and should not be interpreted as an indication of infection in the absence of other symptoms or signs.

Antihistamines

• Antihistamines may be used to treat associated nasal and other allergy symptoms.
• Older antihistamines are effective but also have significant anticholinergic effects, which can lead to sedation, reduced mental alertness and drying up of secretions. Non/less sedating antihistamines (cetirizine, fexofenadine, loratadine and desloratadine) have minimal or no anticholinergic effects and are the preferred option for most people.

Sedatives

• Sedatives are contraindicated during an acute asthma attack.
• Agitation during an attack may be due to bronchospasm and hypoxaemia and is better treated with beta₂ agonists and oxygen.
• Most sedatives, including benzodiazepines and zopiclone (and to a lesser degree, zolpidem), will blunt respiratory drive.

Medications that can exacerbate asthma

A person with asthma who is started on any new medication for another health condition should be advised to make sure they carry their reliever with them, and to watch for deterioration in their asthma. If deterioration occurs they should seek medical advice.

• Certain medications are known to trigger asthma. Others may adversely affect asthma control.
• All patients with asthma (and/or their carers) should be advised to ask their doctor or pharmacist about the effect a new medicine may have on their asthma.
• To facilitate the process, emphasise to people with asthma the benefits of continuing care by one doctor who will be aware of the patient's asthma when prescribing other medications.
• It is also an advantage to have medications dispensed by the one pharmacist or pharmacy, as they may be aware of a person's health conditions and lifestyle factors.

Medication-induced asthma can be separated into predictable and unpredictable/idiosyncratic asthma reactions. Predictable bronchoconstriction may occur with:

• Beta blockers (used in the management of hypertension, cardiac disorders, migraine and glaucoma).
• Cholinergic agents (e.g. carbachol, pilocarpine).
• Cholinesterase inhibitors (e.g. pyridostygmine).

Unpredictable medication-induced asthma exacerbations may occur due to aspirin and other non-steroidal drugs (including cyclooxygenase-2-inhibitors) used for arthritis and inflammatory disorders.

• Be aware of the triad of nasal polyps, asthma and aspirin intolerance.
• An asthma exacerbation caused by NSAIDs is characterised by flushing and rhinorrhoea, often within a few minutes to an hour after administration.
• Other drugs that may cause reactions include carbemazepine and parenteral drugs: penicillin, iron dextran complex, hydrocortisone, ipratropium bromide, aminophylline, N-acetyl cysteine, and preservatives such as bisulfites, metabisulfites and benzalkonium chloride.

Content Created (Thursday, 16 November 2006)