Respiratory & Antihistamine

What are respiratory drugs?

Respiratory drugs causes widening of the airway by relaxing bronchial smooth muscles by stimulating beta receptors.

Common respiratory diseases

• Asthma

  • Asthma is a chronic disease characterized by hyper responsive airways

• Chronic obstructive pulmonary disease (COPD)

  • COPD, includes emphysema and chronic bronchitis

• Allergic Rhinitis

  • Allergic rhinitis is characterized by itchy, watery eyes, runny nose, and a nonproductive cough associated with persisting cough

• Coughing

  • Coughing is an important defensive respiratory response to irritants and has been cited as the number-one reason why patients seek medical care
  • A troublesome cough may represent several etiologies such as:
    • The common cold
    • Sinusitis
    • An underlying chronic respiratory disease

Lifestyle Changes

• Respiratory conditions can be controlled through an appropriate lifestyle changes and medications
• Drugs can be delivered topically to the nasal mucosa, inhaled into the lungs, or given orally or parenterally for systemic absorption
• Local delivery methods, such as nasal sprays or inhalers, are preferred to target affected tissues while minimizing systemic side effects
• Clinically useful drugs mitigate the specific pathology, such as by relaxing bronchial smooth muscle or modulating the inflammatory response

Examples of respiratory drugs

1. Bronchodilators
2. Anticholinergic
3. Mast cell stabilizers
4. Corticosteroids
5. Anti-histamines

1- Bronchodilators:

They causes widening of the airway by relaxing bronchial smooth muscles by stimulate beta receptors.

Indications/uses

• Relieving the distress of asthma
• Bronchospasm or bronchoconstriction.

Drug examples:

Salbutamol, Terbutaline, Albuterol

2- Anticholinergic:

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.

Indication/Uses

• To treat and prevent bronchospasm.
• To treat asthma, bronchitis, emphysema

Drug examples

Theophylline, Etiophylline, Aminophylline

3- 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 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.

Indication / uses

• Prevent asthma symptoms from occurring or prophylaxis to asthmatic attack.
• To decrease inflammation or bronchospasm.
• To decrease allergic reactions.
• Rhinitis/conjunctivitis.

Drug examples

Cromolyn sodium, Sodium cromoglicate

4- Anti-Inflammatory Drugs (Cortico-steroids)

These drugs have antiinflammatory as well as antiallergic actions thus they are effective in bronchial asthma.

They prevent the release of or counteract the bronchial mediators (Kinins, serotonin, Histamine) that cause tissue inflammation responsible for edema and airway narrowing.

Indication/uses

• Chronic bronchitis.
• Allergic Rhinitis.
• Respiratory inflammatory disorders.
• Bronchial asthma.
• Prophylaxis in exercise induced asthma.
• Allergic reaction.

Drug examples

Prednisolone, Beclomethasone Dipropionate, Budesonide, Fluticasone, Betamethasone Valerate

5- Antihistamines

Antihistamines are the drugs used in the treatment of allergic disorders and some other conditions.

These drugs block the effect of histamine and its receptors. They also provide some sort of sedation. There are four types of antihistamines drugs.

1. Highly sedatives.
2. Moderate sedatives.
3. Mild sedatives.
4. Non sedatives.

Indications/Uses

• Allergic reactions (Hay fever, vasomotor rhinitis urticaria, asthma, Anaphylaxis).
• Because of their anticholinergic actions they are used as antiemetic and useful in motion sickness. As hypnotics, Mild sedative/anxiolytics.
• Parkinsonism.

Drug Examples

Diphenhydramine, Promethazine, Hydroxyzine

6- Mucolytics

These drugs reduced the viscosity of sputum that leads to easily expel the sputum.

Decrease mucous viscosity by breaking or altering mucoproteins present in sputum.

Indications/uses

• To treat abnormal viscid, or thick and hard mucus.
• As an antidote for acetaminophen overdose (acetylcysteine)

Drug examples

Acetylcysteine, Bromhexine

7- Decongestants

A Decongestant drugs used to relieve nasal congestion in upper respiratory tracts.

Decongestants are sympathomimetic drugs that act by stimulating 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.

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.

Drug examples

Oxymetazoline hydrochloride, Pseudoephedrine hydrochloride