Metered-Dose Inhaler (MDI)

Inhaler (MDI)

learning outcomes

At the end of the
session students will be able to:

  1.  Justify scientific role of metered dose

  2. Discuss
    on various components of MDI

  3. Recall
    types of MDI

  4. Enlist
    the advantages and disadvantages of MDI

  5. Explain
    proper usage of MDI

  6. Appraise
    applications of MDI


       Pressurized metered
dose inhalers (MDIs) were first introduced in 1950s.

have become the most widely used delivery system for the treatment of lung
diseases such as asthma and chronic obstructive pulmonary disease (COPD).

MDI is readily recognized by the majority of patients who have ever received
treatment for asthma in developed countries and, increasingly so, in developing

        Between 2002 and 2008, 47.5% of inhaled
medications sold in Europe were MDIs.


MDI (metered dose inhaler) is a device that used to deliver
a specific amount of medication to the lungs.

Metered dose inhalers were first developed in 1955 by
Riker Laboratories, Now a subsidiary of 3 M Healthcare

Metered Dose Inhaler (MDI) has a pressurized container of
medication that fits into a mouthpiece

A dose of medication is released into lungs by pushing the
container into the mouthpiece.

Metered-dose inhaler

A metered-dose inhaler (MDI) is a device that delivers a
specific amount of medication to the lungs, in the form of a short burst of
aerosolized medicine that is usually self-administered by the patient via

Metered dose inhalers (MDI) also provided a versatile,
reliable, instantly available, self-contained, portable, low cost medical
aerosol delivery system for more than 35 years.


1. The canister which is produced in aluminium or
stainless steel by means of deep drawing, where the formulation resides.

2. The metering valve which allows a metered quantity
of the formulation to be dispensed with each actuation.

3. An actuator or mouthpiece which allows the patient
to operate the device and directs the aerosol into the patient’s lungs.

4. Actuator seat:

It holds metering valve and actuator nozzle.

5. Actuator nozzle:

It helps to spread the component into the mouth.

diagram of metered dose inhaler (MDI).

Types of MDI.

MDIs (Metered Dose Inhaler) are classified in two categories

1.       Non-pressurized

2.       Pressurized

Non-pressurized MDI.

Portable, inhalation delivery device containing an aqueous solution,
suspension or emulsion, which delivers one dose in one or more actuators.

Pressurized MDI.

An inhalation product containing one or more propellants in
a pressurized delivery device.

How do we
use a metered dose inhaler?

 General steps for COPD:

1. Remove the cap from the metered dose inhaler.

2. Shake the inhaler for a few seconds.

3. Place our index finger on top of the canister and thumb
on the bottom of the mouthpiece.

4. Tilt our head back slightly and breathe out.

5. Hold the inhaler upright about the width of two fingers
from our mouth.

6. Press down on the inhaler once as we breathe in as slowly
and deeply as we can about 3-5 sec.

7. If possible, hold our breath for at least 10 seconds.

8. If our doctor prescribed more than one puff of COPD
medication, wait about 1 minute and repeat steps 2-8.

9. Replace the cap on the metered dose inhaler.

10. Gargle and rinse our mouth with water or mouthwash
(usually advised only for steroid-type inhalers).

What is a spacer?

spacer is a tube that attaches to a metered dose inhaler (MDI).It holds the
medication until you can breathe it in. The spacer ensures that anyone who does
not use the device correctly gets the COPD medicine from the MDI to their
lungs. For this reason, it also lessens side effects.

How do I use a metered dose inhaler with a spacer?

the caps from the metered dose inhaler and spacer.

        Insert the inhaler into the open end of the

the inhaler for a few seconds.

out completely.

the mouthpiece of the spacer between your teeth. Seal your lips tightly around

the canister once to dispense the medication into the spacer.

        Breathe in slowly through your mouth for about
3 to 5 seconds. If you hear a hornlike sound, slow down. This means you are
breathing too quickly.

your breath for at least 10 seconds.

        If your doctor prescribed more than one puff
of COPD medication, wait about 1 minute and repeat steps 3-8.

the spacer from the inhaler and replace the caps on the inhaler and spacer.

and rinse your mouth with water or mouthwash

Types of MDI with brand names

Inhaled Corticosteroids: Control respiratory disease
by suppressing overactive immune response in the lungs which can cause
inflammation. Various brand names 
are available such as Flovent, Azmacort, Beclovent, Vanceril,
Budesonide, Qvar and Aerobid.

Inhaled Bronchodilators: Relax the smooth muscles of
the lung airways preventing spasms that restrict or cut off the air supply.
There are two types of bronchodilators available: long acting and short acting.
They are available in different brand names as Ventolin, Proventil, Maxair,
Xopenex, Alupent and ProAir.

→Combination Inhalers: Corticosteroids and
long-acting bronchodilators are also available in combinations for ease of use
and efficacy. Brand names available for metered dose inhalers combining both a
steroid and bronchodilator are Advair and Symbicort.

of MDIs

it is small size & convenience to patients.

it is inexpensive as compared to Dry Powder Inhaler (DPI) & Nebulizer.

to use than other device

drug delivery

delivery capability more  than hundred
(100) dose are available

charges  does not reduce drug delivery to
the lungs

risk of bacterial contamination

        Allows pressurized metered dose inhaler use in
patient with acute  illness

drug preparation is needed.

of MDIs

correct actuation and inhalation coordination.

to hold breath after inhalation.

drug deposition.


possibility of new HFA propellants.

of MDIs

commonly used delivery system for treating asthma, chronic obstructive
pulmonary disease (COPD) and other respiratory diseases.

medication in a metered dose inhaler is most commonly a bronchodilator,
corticosteroid or a combination of both for the treatment of asthma and COPD.
Other medications less commonly used but also administered by MDI are mast cell
stabilizers, such as cromoglicate or nedocromil.

For Image Based Detailed PDF Notes Click on Download Button

Leave a Comment