6 Medications That Can Trigger An Asthma Attack: What Drugs Should Asthmatics Avoid?

Asthma is a chronic inflammatory disease of the airways. Regardless of the cause, the basic pathology includes airway obstruction, increased mucus secretion and accumulation, and swelling due to inflammation. Giving the complex mechanisms involved in the pathology of asthma, there are many drugs asthma patients should avoid, and some of them are even marked as contraindicated because they can cause asthma attacks or have negative interactions with asthma medications.

Beta blockers

The main role of beta blockers is to block beta-adrenergic receptors in heart cells, smooth muscles in the walls of the blood vessels, and other smooth muscles. They are usually used to treat high blood pressure (hypertension) and various heart-related conditions. Depending on the need, doctors can prescribe beta blockers which are selective for one specific type of tissue. For example, beta-1-blockers (atenolol) are selective for the beta-1 adrenergic receptors, which are found in the heart and in the kidneys. Non-selective beta blockers act on all types of beta receptors, which are found in various organs, including the lungs and the airways.

ACE inhibitors

Inhibitors of the angiotensin-converting enzyme (ACE) are the most common drug group used for the treatment of hypertension, along with diuretics. They are designed to block the conversion of angiotensin I to angiotensin II, which normally occurs in the lungs. However, there is a side effect. They also interfere with the process of bradykinin breakdown in the lungs, which causes a cough in roughly one tenth of patents who use them. Patients who suffer from asthma already have cough as one of the main symptoms, so ACE inhibitors can make that cough much worse by further irritating the airways and increasing bradykinin levels. Again, there are safer alternatives for asthma patients with hypertension.

Aspirin and NSAIDs

Aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) are used as painkillers and anti-inflammatory drugs. Aspirin has additional uses in cardiology and it is often prescribed to patients with angina pectoris. Patients with heart attack receive as initial therapy a higher dose of aspirin, in order to stop the aggregation of platelets. Aspirin and NSAIDs have a complex mechanism of action. They block the biochemical pathways through which the arachidonic acid converts to prostaglandins (cyclooxygenase pathways — COX1 and COX2). In turn, there is an excess of arachidonic acid, which then enters the lipoxygenase pathway, resulting in increased production of leukotrienes.

In asthma, leukotrienes are considered the main mediators of chronic inflammation. Therefore, aspirin and NSAIDs should not be used in asthma patients because they increase the levels of leukotrienes. For pain relief, acetaminophen (paracetamol) is offered as a much safer alternative in asthma patients.

Dipyridamole

Similarly to aspirin, dipyridamole is an antiplatelet drug, which is given to patients with heart attack or ischemic stroke in high doses, in order to prevent further clotting (secondary prevention). It can also be prescribed to patients with peripheral artery disease. Dipyridamole increases the levels of adenosine, which then relaxes smooth muscles in the blood vessels.

There were many animal studies investigating this phenomenon and there is also a case report showing respiratory arrest after venous administration of dipyridamole in persons with chronic lung disorder. The use of dipyridamole is therefore not recommended in patients with asthma.

Estrogen supplementation

It is well-known that asthma is more common in women than in men. Furthermore, women have severe forms of asthma more commonly than men. There are several hypotheses, but the most logical one is that female sex hormones play an important role in the development of asthma.

After many years of research, it has been concluded that estrogen has a strong impact on the health of the respiratory system, although there are several proposed mechanisms of its action which could contribute to the development of asthma and worsening asthma symptoms.

Animal studies have shown that estrogen is involved in several pathophysiological pathways, some of them having to do with hyperactivation of the Th2 immune response (which is mainly responsible for allergic reactions). Scientists have also noticed that asthma symptoms severity changes with aging in women, and also throughout the menstrual cycle, peaking during the peri-menstrual days (few days before and after the first day of menstrual bleeding). This is also the time when the levels of estrogen and progesterone are the highest in the cycle.