Medications for asthma and COPD (Chronic Obstructive Pulmonary Disease) can be administered either by inhaled or systemic routes. Systemic routes, which can be oral (ingested) or parenteral (subcutaneous, intramuscular or intravenous), are not common, because they present several drawbacks:

• Tend to be slow-acting (at least 20-30 minutes are necessary for the onset of action)
• Are not targeted, therefore can have systemic effects
• Require relatively high doses to overcome the first-pass effect (metabolization through the liver), and this adds to its potential of systemic, unwanted effects.

There is international consensus that treatment by inhalation is the preferred form of therapy for asthma and COPD patients, because, delivering the drug directly to the airways, the risk of significant side effects experienced with other medications is reduced.

Inhaled therapies have the following advantages:

• They deliver the active ingredient directly to the lungs. This targeted delivery achieves an extremely rapid onset of action (that is mandatory when symptomatic relief is required): the patient can obtain relief within one or two minutes after inhalation.
• A much lower dose of medication is needed compared to the oral delivery, allowing for effective treatment with minimal systemic exposure.

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Four types of inhalation delivery systems are available

• Pressurized Metered Dose Inhalers (pMDIs)
• Dry Powder Inhalers (DPIs)
• Breath-Activated Metered Dose Inhaler (BAIs)
• Nebulizers

Because these four systems are not equally suitable for all patients, it is essential to maintain each of these therapeutic options if individual patient needs are to be met.