Inhaler devices are still a major hurdle in asthma and COPD treatment
London, UK - Although the inhaled delivery of drugs has major advantages over other methods of administration, inhaler devices are often difficult to use and can indirectly have a negative impact on symptom control. Unfortunately, in a classic catch-22 situation, those devices that are developed to overcome the disadvantages of the majority of inhalers often lack broad availability across different therapeutic molecules and drug classes.
Offering physicians and patients a range of therapies in the same type of device will therefore improve proper use of inhalers, which can indirectly have a positive impact on the control of diseases like asthma and chronic obstructive pulmonary disease (COPD), according to a new report* by independent market analyst Datamonitor.
Benefits of inhalers obvious Respiratory diseases like asthma and COPD are mostly treated with inhaled drugs in order to relieve bronchoconstriction and target inflammation in the lungs. There are several advantages to administering these drugs via the inhaled route compared to oral therapy: a faster onset of action, lower drug doses and a better efficacy-to-safety ratio. Drug delivery by inhalation is also painless and is more convenient than injectable drugs.Despite this impressive list of benefits, several drawbacks remain for inhaled medicines, explains Datamonitor respiratory analyst Lisette Oversteegen.
"One of the biggest problems relates to the inhaler device through which the drug is delivered. Every type of device is different and requires a specific inhalation technique in order to get a sufficient amount of drug to the lungs. "Since there are so many different types of inhalers available, it can be difficult for the patient to learn and remember the correct use for each one of them. An incorrect inhalation technique is likely to have a big impact on a patient's daily life, since their asthma or COPD symptoms could be less well controlled than optimally possible," she says. All types of inhaler devices have major disadvantages.
There are two main types of portable inhaler devices used in the treatment of asthma and COPD: metered dose inhalers (MDIs), including pressurized MDIs (pMDIs) and breath-activated MDIs (BAIs), and dry powder inhalers (DPIs) (including single-unit dose DPIs, multi-dose reservoir DPIs and multi-unit dose DPIs).The standard pMDI is the oldest and most often-used inhaler since it is cheap and available containing many different molecules. Nonetheless, a large proportion of patients cannot use them correctly.
One of the most common problems is a failure to co-ordinate inhalation with actuation of the device (pressing the canister to release the drug). Patients often actuate the inhaler before or at the end of inhalation, and some may even hold their breath while activating the inhaler. Other errors include failure to exhale fully before inhalation and failure to continuously inhale slowly after actuation. Because of the problems associated with pMDIs, attention has focused on the improvement of inhaler devices to optimize the delivery of medication. Breath-activated MDIs (BAIs) help to overcome the problem of co-ordinating actuation with inhalation, thus providing the opportunity to improve drug delivery and overall disease control. However, the major drawback of BAIs is that there are only a few drugs available in these devices due to the high cost involved in developing them, Miss Oversteegen says.
"Since physicians cannot offer all of the medicines a patient needs in a BAI, they are forced to switch back to a pMDI or combine different devices in one treatment regimen." Dry powder inhalers offer an alternative response to the difficulties associated with pMDIs. These devices release the drug by passing air from the patient's inhalation effort through medication formulated as a dry powder. Although this partially resolves the co-ordination problem since the drug is only released when the patient inhales, there are other disadvantages to DPIs, Miss Oversteegen says.
"While the inhalation technique for pMDIs is generally the same, the wide variety of DPIs available means that inhalation instructions can be very different."Furthermore, to ensure that most of the drug emitted from a dry powder inhaler reaches the lungs, it is necessary for the patient to inhale deep and fast enough. A number of asthma and COPD patients are unable to do so, especially the elderly, children and people with severe airflow limitation," she says.
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