Respiratory agents drugs

Drugs used in Respiratory System
Respiratory agents is a term used to describe a wide variety of medicines used to relieve, treat, or
prevent respiratory diseases such as asthma, chronic bronchitis, chronic obstructive
pulmonary disease (COPD), or pneumonia.
Respiratory agents are available in many different forms, such as oral tablets, oral liquids,
injections or inhalations. Inhalations deliver the required medicine or medicines directly to the
lungs, which mean the medicine, can act directly on the lung tissues, minimizing systemic side
effects.
Some products contain more than one medicine (for example, inhalers that combine a long-
acting bronchodilator with a glucocorticoid)
Anti-Asthmatic Drugs
Definition: Drugs used to treat bronchial asthma
Classification of Anti asthmatic drugs
1. Bronchodilators
a. Beta Adrenergic Agonist or sympathomimetics.
 Non selective beta adrenergic agonist :
 Epinephrine
 Ephedrine
 Isoproterenol
 Selective beta adrenergic drugs:
 Albuterol
 Terbutaline
 Metaproterenol
 Pirbuterol
 Bitolterol
 Salmotero
 Formoterol
b. Methylxanthines.
2. Anti inflammatory agents
 Mast cell stabilizers
 Corticosteroids.
3. Anti-histamines.
4. Leukotriene inhibitors:
5. Anti IgE Drug

1. Bronchodilators: Adrenergic agonist or sympathomimetics
a. Non selective beta adrenergic agonist :
Epinephrine:
 It stimulates alpha and beta1as well as beta2 receptors.
 It is an effective rapid acting bronchodilator when injected S/C (0.4 mL of
1:1000 solution) or inhaled as a microaerosol from a pressurised canister (320
mcg/ puff).
Adverse effects
 Tachycardia,
 Arrythmias
 Worsening of angina pectoris.
Ephedrine:
 Used in asthma for longest time.
 Longer duration and lower potency than epinephrine.
 Not much used nowadays due to development of β2- selective agents.
Isoproterenol:
 A potent bronchodilator , producing effect in 5 minutes.
 Duration of action 60-90 minutes.
 High doses associated with cardiac arrhythmias leading to death.
b. Selective beta adrenergic drugs:
Mechanism of action: They causes widening of the airway by relaxing bronchial smooth
muscles by stimulate beta receptors.
Drug examples & Doses

Indications/uses
 Relieving the distress of asthma.
 Bronchospasm or bronchoconstriction.
Contraindications/ Precautions.
 Patient with uncontrolled arrythmias.
 Prolonged use of albuterol may cause hypokalemia
Adverse Effects
 Nervousness.
 Anxiety.
 Tremor.
 Headache.
 Palpitations.
 Tachycardia.
 Arrhythmias.
Drug interactions
 (Beta) blocker antagonize the effects of adrenergic agonists.
 Prolonged use of theophylline cause additive effects.
Nursing Responsibilities
 Nurse should monitor the patient’s blood pressure, pulse, respiratory rate, and breathing
sounds.
 Teach the patients that how to use inhalers.
 Instruct the patient to avoid respiratory irritants, such as smoke, dust, and strong smell.
c. Bronchodilators: Methylxanthine
Mechanism of action: These drugs are weak CNS stimulants that are powerful smooth muscle
relaxants thus they relax the smooth muscle of bronchi. They also have diuretic effect.
Drug examples & Doses

Indication/Uses
 To treat and prevent bronchospasm.
 To treat asthma, bronchitis, emphysema.
Contraindications/ Precautions
 Hypersensitivity to any xanthine.
 Infection or irritation of rectum or lower portion.
 Give cautiously in neonates, in elderly patients, heart disorders hepatic disorders.
Adverse effects
 Headache.
 Anxiety.
 Nausea.
 Seizures.
 Abdominal Cramping.
 Diarrhea.
 Respiratory arrest.
 Irritability.
 Insomnia.
 Vomiting.
 Peptic ulcer.
 Epigastric pain.
 Tachycardia.
Drug interactions
 (beta) Blocker may antagonize the effects of methylxanthines.
 Erythromycin may increase the half life of methylxanthines, and increasing the risk of
methylxanthines toxicity.
 Rifampicin, phenobarbital phenytoin, cigarette smoking and charcoal – broiled food may
shorten the half-life of drugs and reducing their effectiveness.
 Nurse should assess for signs and symptoms of toxicity.
 Nurse also should know that therapeutic sr. level of theophylline ranges from 10 to 20
mcg/ml.
 Advise patients to decrease consumption of xanthine – containing food and beverages.

 To detect toxicity, nurse should monitor serum drugs levels.
ANTI INFLAMMATORY DRUGS
a. Mast cell Stabilizers
Mast cell stabilizers works to prevent allergy cells called mast cell from breaking open and
releasing chemicals that help to cause inflammation.
They are not effective once the allergic reaction has occurred and mediators are released from
mast cells. So they are useless during asthmatic attack. They are used in the prophylaxis of
asthma.
Mechanism of action
They inhibit mast cell activity, thus prevent the release of allergic mediators like histamine,
serotonin, prostaglandins, cytokines. These chemical are essential for an inflammation and
allergic reactions.
Drug examples and Doses
Indication / uses
 Prevent asthma symptoms from occurring or prophylaxis to asthmatic attack.
 To decrease inflammation or bronchospasm.
 To decrease allergic reactions.
 Rhinitis/conjunctivitis.
Contraindications/ precautions
 Hypersensitivity.
 Precautiously with renal dysfunction, hepatic dysfunction.
 Lactation, Cardiac arrhythmias.
Adverse effects
 Throat irritations.
 Nasal irritations.

 Wt. Gain.
 Headache.
 Drowsiness.
 Dry mouth.
 Dizziness.
Drug interactions
 Not reported
 Nurse should monitor drugs adverse reactions.
 Instruct patients that this drug is not effective in an acute attack.
 Nurse should instruct the patient how to use metered – dose inhaler or nebulizer.
 If more than one inhalation is ordered, advise patient to wait 1-2 minutes before taking
second puff.
 If the parents is also receiving an inhaled bronchodilator, advise the patient to use
bronchodilators first to open the airways and then wait approximately 5min before using
cromolyn sodium to maximize its effectiveness.
b. Anti-Inflammatory Drugs (Cortico-steroids)
These drugs have antiinflammatory as well as antiallergic actions thus they are effective in
bronchial asthma.
Mechanism of action
They prevent the release of or counteract the bronchial mediators (Kinins, serotonin, Histamine)
that cause tissue inflammation responsible for edema and airway narrowing.
Drug example and dose

Indication/uses
 Chronic bronchitis.
 Allergic Rhinitis.
 Respiratory inflammatory disorders.
 Bronchial asthma.
 Prophylaxis in exercise induced asthma.
 Allergic reaction.
Contraindications/precautions
 Acute bronchospasm.
 Use cautiously in patients who are immunosuppressed and in those taking prednisone or
other corticosteroids.
 Use very cautiously in patients with viral respiratory infections.
Adverse effects
 Hoarseness.
 Candida infections.
 Oropharyngeal irritation.
 Bronchospasm after inhalation of dry powder.
Drug interaction
 Generally Not reported but can be find drug specific.
 Nurse should instruct the patient to rinse his mouth, after using inhaled steroids.
 Nurse should teach the patient to:
o Use bronchodilators several minutes before glucocorticoid inhaler.
o Rinse mouth after using inhaled steroids.
o Use and care for inhaler properly
Antihistamines
Antihistamines are the drugs used in the treatment od allergic disorders and some other
conditions.

Mechanism of action
These drugs block the effect of histamine and its receptors. They also provide some sort of
sedation.
Types
There are four types of antihistamines drugs.
 Highly sedatives.
 Moderate sedatives.
 Mild sedatives.]
 Non sedatives.
Drug Example & Doses

Indications/Uses
 Allergic reactions (Hay fever, Vasomotor rhinitis urticaria, asthma, Anaphylaxis).
 Because of their anticholinergic actions they are used as antiemetics and useful in motion
sickness.
 As hypnotics, Mild sedative/anxiolytics.
 Parkinsonism.
 Hypersensitivity.
 Lactation.
 Hypokalemia.
 Neonate.
 Coma.
 Special precautions in acute asthma and pregnancy, elderly, epilepsy.
Adverse effects
 Drowsiness in common.

 Delirium.
 Convulsions
 Due to anticholinergic effect
 Urinary retention.
 Constipation.
 Dryness of mouth.
 Blurring of vision. .
 Severe toxicity may causes death to cardiac and respiratory failure.
 Antihistamines are best given in the evening since all antihistamines cause drowsiness.
 Advise to patient not to drive vehicle or do not operate machinery.
 Advise to patient to avoid sedative such as alcohol or sedative hypnotics.
Leukotriene inhibitors:
They act against one of the inflammatory components of asthma and provide protection against
bronchoconstriction when taken before exercise or exposure to allergen or to cold air.
Examples of leukotriene inhibitors include montelukast and zafirlukast.
Side effects
 Abdominal pain
 Thirst
 Headache
 Hyperkinesia (in young children)
Cautions
 Should not be used for the treatment of acute asthma attacks
 Caution in pregnancy and breastfeeding
Anti Immunoglobulin E (Anti-IgE)
Action by blocking immunoglobulin E,which causes of inflammation in allergic asthma.
Anti-IgE therapy is only available by prescription. Unlike other asthma medications, it is not
administered by pill or by inhaler. It needs to be injected once every two or four weeks by a
doctor or other trained healthcare professional.
Example is omalizumab (Xolair®).

Side Effects
The most common side effects of anti-IgE therapy are: skin irritation or reaction at the site of the
injection, and respiratory tract infections (e.g., common cold).
Mucoactive agent
Mucoactive agents are a class of drugs which aid in the clearance of mucus from the upper and
lower airways, including the lungs, bronchi, and trachea. Mucoactive drugs include expectorants,
mucolytics, mucoregulators, and mucokinetics. These medications are used in the treatment
of respiratory diseases that are complicated by the oversecretion of mucus. The drugs can be
further categorized by their mechanism of action
Types
 Expectorants – increase airway water or the volume of airway secretions
 Mucolytics – thin (reduce the viscosity of) the mucus
 Mucokinetics – increase transportability of mucus by cough
 Mucoregulators – suppress underlying mechanisms of mucus hypersecretion
.
Mucolytics
These drugs reduced the viscosity of sputum that leads to easily expel the sputum.
Mechanism of action
Decrease mucous viscosity by breaking or altering mucoproteins present in sputum.
Drug example & Doses

Indications/uses
 To treat abnormal viscid, or thick and hard mucus.
 As an antidote for acetaminophen overdose (acetylcysteine).
 Hypersensitivity to these drugs.
 Cautiously in elderly, pregnant or breast feeding mothers.
Adverse effects
 Stomatitis.
 Drowsiness.
 Bronchospasm.
 Nausea/vomiting.
 Severe rhinorrhea.
Drug interactions
 Activated charcoal decreases acetylcysteine effectiveness.
 Incompatible with chlortetracycline, erythromycin, amphotericin B, Hydrogen peroxide.
 To assess the airway and maintain it patent.
 Provide suction if needed.
 Assess the pattern breath sounds, cough, and bronchial secretions.
 Advise patient to maintain a fluid intake of 2- 3litres/day.
 Warn the patient about the rotten egg smell of acetylcysteine.
Decongestants
A Decongestant drugs used to relieve nasal congestion in upper respiratory tracts.

Mechanism of action
Decongestants are sympathomimetic drugs that act by stimulating the α (alpha) – adrenergic
receptors. The decongestant effect due to vasoconstriction of the blood vessel in the nose sinuses
etc. the vasoconstriction effect reduces swelling or inflammation and mucous formation in the
nasal passage and make it easier to breath.
Drug examples and doses
Indications /uses
 For temporary relief of nasal congestion due to common cold.
 Hay fever.
 Sinusitis.
 Upper respiratory tract allergens.
 To promote nasal and sinus drainage.
 Hypersensitivity to these drugs.
 MAO (Monoamine oxidase) inhibiters drugs therapy.
 Use cautiously in older age patient they are more likely to experience adverse reaction.
 Nasal contestant should not be used for more than three days, and oral decongestant
should not used more than 7days because prolonged use will result in rebound
congestion.
Adverse Effects
 Arrhythmias.
 Tachycardia.

 Insomnia.
 Palpitation.
 Hypertension.
 Drowsiness.
 Hypersensitivity reactions including rash, urticaria.
Drug interactions
 If given with other sympathomimetic amines may increase central nervous system
stimulation.
 If given with MAO inhibiters may cause severe hypertension.
 Nurse should assess adverse effect of drugs.
 Monitor pulse rate, BP, and ECG.
 Advise patient not to share the container with other people and not allow the tip of the
container to touch the nasal passage to avoid contamination.
Drugs for cough
The drug which used in cough are:
 Antitussive.
 Expectorants.
 Bronchodilators.
Antitussives (Cough center suppressant)
A. Opioids – Codeine, pholcodine.
B. Non opioids – Noscapine, dextromethorphan.
C. Antihistamine – Chlorpheniramine diphenhydramine.
Expectorants
A. Bronchial secretion enhances – Sodium or Potassium Citrate, Potassium Iodide,
Ammonium Chloride.
B. Mucolytes – Bromhexine ambroxol, Acetylcysteine.
Bronchodilators – already explained
eg: Salbutamol, Terbutaline.

Antitussives
They are used to suppress dry cough mostly because their aim to control rather than eliminate
cough. These are also called cough center suppressants.
Mechanism of action
These are the drugs that act in the CNS to increase threshold of cough center.
Drug example & Doses
Indications/uses
 Dry & unproductive cough.
 Allergic cough.
 Spasmodic cough.
Adverse Effects
 Constipation.
 Drowsiness.
 Dryness of mouth.
 Irritability.
 Ataxia.
 Respiratory depression in higher doses.
 Addiction.
 Vertigo.
 Nausea
 Headache.
Contraindication/precautions
 Respiratory Depression.

 Asthmatics.
 Convulsion disorder.
 Contraindicate while driving.
 Obstructive airway disease.
 Assess the side effects or adverse reaction during the therapy.
 Special precaution should be keep in mind before drug administration.
 Advise to patient not to driving after taken opioids drugs such as codeine pholecodiene.
Expectorants
These drugs help in removal of secretions of respiratory tract and mucolytic agents produce
liquification of mucous making expectoration easier.
Mechanism of action
They increase bronchial secretions or reduce its viscosity, sodium and potassium citrate increase
bronchial secretion by salt action also these drugs stimulate gastric mucosa or directly acting on
mucous membrane of lungs to increase the secretion of mucous.
Indications/uses
 Chronic productive cough.
 Thick mucous production.
 Combinations with antitussives drugs for relieving cough.
Adverse effect
 Allergic reactions / hypersensitivity.
 Rhinorrhea.
 Lacrimation.
 Gastric irritation.
Contraindication/precautions
 History of peptic ulceration.
 Asthmatic patients.
 Severe hepatic or renal function.
Drug interactions

 They may increase the risk of bleeding when use with anticoagulants.
 Advise to take plenty of fluid during this therapy to easier removal of thick mucous.
 Assess the adverse effect
Expectorants
The clinical use of expectorants is controversial as their efficacy is still the subject of debate
.Expectorants are purported to reduce the viscosity of respiratory tract secretions and facilitate
the removal of accumulated mucus and phlegm by ciliary action and coughing. By increasing
respiratory tract secretions, expectorants may also soothe dry, irritated tissues and, in so doing,
may reduce the urge to cough. They may also make a dry, unproductive cough more productive.
Inhalational Drug Delivery Devices
Many respiratory drugs are delivered topically to the airway by inhalational devices – this
achieves an effect on the airways with a rapid onset of action and minimal systemic adverse
effects.
The devices available for drug delivery are metered dose inhalers (MDIs), commonly known as
‘puffers’ and used with or without spacers, and nebulisers. Errors of technique occur with all
devices, so it is important to check patient technique at each review. Demonstration and
repetition are essential for achieving optimal patient technique.
Metered dose inhalers (MDIs) or “puffers”
A metered dose inhaler (MDI) or puffer is a multidose device usually containing micronised
powdered medication and a propellant system such as hydrofluoroalkane (HFA). Care of
these devices is important and the following should be observed:
 The majority of puffers need to be washed regularly to avoid blockage
 The recommended frequency of washing ranges from daily to monthly, depending on the
device. Refer to the specific product information for directions.
 Patients should shake the device every time before using it. If there appears to be very
little liquid inside the canister when shaken, it is time to replace it.
Technique in the use of MDIs

Correct technique is vital in the use of MDIs. Since up to seventy percent of patients use an
incorrect technique with a puffer resulting in inadequate drug delivery to the lungs, the
following steps should be observed:
 Check patient technique and demonstrate the correct technique (if necessary) at every
opportunity. It has been shown that there is deterioration in technique within two months
of correct demonstration.
 The device should be held upright with the mouthpiece at the bottom. This allows an
accurate dose to be dispensed into the actuator valve.
 Deposition of the drug from the inhaler to the airway is achieved by coordinating the
actuation of the puffer and inhalation of the aerosol mist.
 Starting at the end of a normal expiration, the puffer should be actuated once at the
same time as a slow deep inspiration through the mouth is undertaken. At the completion
of the slow deep inspiration, the breath should be held for approximately 10 seconds.
There are two techniques which are both satisfactory if performed well:
Closed mouth – where the lips are sealed around the mouthpiece of the MDI.
Open mouth – where the inhaler is held up to 6 cm away from the mouth.
The common errors when using puffers include the following:
 Failing to coordinate the puffer actuation with the start of the inspiration
 Inspiring too rapidly
 Closing the mouth and then inspiring through the nose after actuation of the puffer
 Actuating the puffer more than once during the inspiration
 Failing to hold the breath.
.

Spacer devices
It is often appropriate to use a chamber device with the MDI. These spacers hold the aerosol
cloud, which is produced from an MDI, in a confined space and allow subsequent inhalation over
a longer period. Evaporation of some of the propellant produces particles of smaller size and
gives the potential for greater endobronchial deposition. Spacer devices have a valve system
which can help patients who have problems with coordination. They are particularly useful in
decreasing the oropharyngeal deposition of the medication and increasing the proportion of the
dose delivered to the lung. With inhaled corticosteroids, spacers are an important means of
reducing candidiasis and dysphonia.
Inhalation of aerosol from the spacer should commence as soon after actuation as possible
to minimise deposition in the spacer and loss of the drug. One actuation of MDI per
inhalation is recommended.
Spacer devices with MDI in appropriate doses may be substituted for nebulised medication.
During asthma exacerbations, 4 to 10 inhalations of standard dose short-acting beta2-agonists
can produce a similar bronchodilator effect to standard nebulised doses.
Technique in the use of spacer device
The proper use of a spacer is as follows:
 Shake the MDI before use.
 Insert MDI, mouthpiece down, into the spacer.
 Actuate the MDI.
 Inhale slowly and deeply from the spacer (starting as soon after actuation as
possible).
 Hold breath for 10 seconds.
Two modifications of the use of spacer devices may be applicable for children:
Take four to six tidal breaths to inhale the aerosol.
Use a face mask adapter to inhale from the spacer (for infants and young children).
Care of spacer devices
 Spacers should be washed before initial use and at least monthly thereafter.
 Use kitchen detergent mixed with warm water.
 Leave to drain (without rinsing) and allow to dry before use.

 A cloth should not be used to dry the spacer as this can produce an electrostatic
charge causing drug particles to adhere to the walls of the spacer.
 Before using the spacer, it should be ‘primed’ by actuating three to five doses of
the drug. This minimizes fluctuations in inhaled doses due to variation in
electrostatic charge.
Use of devices in children
MDIs with a spacer and mask can be used in children younger than two years of age. MDIs alone
require a reasonable amount of coordination; therefore, they should not be used without a spacer.
References
 Dr. P.K. Panwar, Essentials of pharmacology for nurses, AITBS pub. 2017, India, Pg no.
49 – 62.
 Dr. Suresh k sharma, Textbook of pharmacology, pathology & genetics for nurses,
Jaypee pub. 2016 India Pg no 161 – 205.
 Tara v. Shanbhag, Smita shenoy, Pharmacology preparation manual for undergraduate,
Elsevier pub. 2014. Pg no. 226 – 257.
 Marilyn Herbert – Ashton, Nancy Clarkson, Pharmacology, Jones & Barlet pub 2010
India, Pg no 225-258.
 Govind s. Mittal, Pharmacology at a glance, Paras medical book pub. 2009 India 18 – 19.
 Madhuri Inamdar, Pharmacology in nursing, Vora medical pub. 2006 India 1 st edition,
Pg no 92 – 98
MATHEW VARGHESE V
MSN(RAK),FHNP (CMC Vellore),CPEPC
Nursing officer
AIIMS Delhi

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