Respi - Medicine for Cough & Cold Flashcards Preview

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Flashcards in Respi - Medicine for Cough & Cold Deck (11):

Classes of cough & cold drugs used & examples

1. Cough Suppressants (Anti-tussives - Codeine, Dextromethorphan)
2. Cough Expectorants (Guaiphenesin)
3. Mucolytics (Carbocysteine, Ambroxol)
4. Antihistamines (1G - Diphenhydramine, Chlorpheniramine, Tripolidine, Promethazine, 2G - Cetirizine, Loratidine)
5. Decongestants (Pseudoephedrine, Phenylephrine, Oxymetazoline)


Mechanism of action & uses of cough suppressants

Suppresses cough centre in the brain

Suppresses irritating, unproductive (no mucus) cough


Toxicity of codeine (3)

Type A ADR, dose related

1. Addictive Potential - 10% converted to morphine
2. Constipation - due to reduced GIT motility (esp chronic)
3. Urinary Retention - due to increased bladder sphincter tone


Mechanism of action of cough expectorants

1. Aids/promotes expulsion of mucus/exudate from the lungs, bronchi and trachea
2. Loosens phlegm/mucous secretion in the airway by increasing water content


Mechanism of action of mucolytics

Breaks down chemical structure of mucus molecules - mucus becomes thinner, can be easily removed through coughing


Mechanism of action of antihistamines

Binds to H1-receptor & eliminates histamine actions (competitive antagonist) - reduces nasal secretion + allergic response


Uses of antihistamines (8)

1. Allergic Rhinitis
2. Common Cold (flu)
3. Allergic Conjunctivitis (red eye)
4. Allergic Skin conditions (rashes)
5. Urticaria (hives)
6. Angioedema (swelling of the deep layer of skin, usually affects eyes, lips, genitals, hands, feet)
7. Anaphylactic reactions (severe allergies)
8. Nausea & Vomiting (1G)


Toxicity of antihistamines (3)

1. 1G - Sedation, dizziness, blurred vision, parasympathetic (constipation, urinary retention, confusion, dry mouth) - lack of selectivity for H1R, has anti-cholinergic activity
2. 2/3G - Drowsiness, fatigue, headache, nausea, dry mouth - more selective for peripheral histamine receptors, less ADRs
3. Terfenadine, astemizole - withdrawn due to cardiotoxicity


Mechanism of action & uses of decongestants

Vasoconstriction in the nasal passage - relieves congestion

Relieves nasal congestion


Considerations when using decongestants

Antihistamines should be taken with decongestants, or else nose will still be clogged with the stuck mucus (if only AH)


Toxicity of decongestants (3)

1. Cardiac Arrhythmia
2. Tachycardia (palpitations)
3. Tremors