Pharma Flashcards
Drugs Used in the Treatment of Asthma:-
A. β-adrenergic agonists
B. Antimuscarinic Agents
C. Theophylline (methylxanthines)
D. Corticosteroids E. Leukotriene Pathway Inhibitors
F. Cromolyn and Nedocromil
Short term relievers:
β- adrenoceptor stimulants, methylxanthines, antimuscarinic agents
Long term controllers:
Corticosteroids, leukotriene antagonists, inhibitors of mast cell degranulation
Mechanism of action of Theophylline
• Inhibition of phosphodiesterase (PDE) leads to increased concentration of cAMP and causing
bronchodilatation. Raised cAMP levels in inflammatory cells may attenuates mediator release and add to the therapeutic effects.
• Adenosine acts as a local mediator and causes contraction of smooth muscles of bronchial and
theophylline blocks it.
Ex- Beclomethasone, Fluticasone, Budesonide
Corticosteroids
Mechanism
They are usually administered in the form of inhaler in order to reduce the risk of systemic side
effects.
The anti-inflammatory effects of steroids is achieved by inhibition of phospholipase A2 leading
to a reduction in the synthesis of the prostaglandins, thromboxane, the leukotrienes and
platelet activating factors.
They also decrease the expression of cyclo-oxygenase (COX-2) and prevent mast cell
degranulation
Corticosteroids
• Inhaled
• Short term – oral candidiasis
• Long term – possibly increased risk for osteoporosis and cataracts
Corticosteroids
Mechanism
• Inhibits cellular activation
effect on mast cells is to prevent degranulation and thus mediator release
• NO EFFECT on airway smooth muscle tone Clinical Uses
1-Prophylactic value only
• Not effective for reversing bronchospasm
Cromolyn
Ex- Montelukast, Zafirlukast, Zileuton
Leukotriene Inhibitors
Drugs to be avoided in patient with bronchial asthma
1.NSAIDS like aspirin, ibuprofen, diclofenac etc (Block synthesis of prostaglandins that have
bronchodilator activity)
2. Non selective Beta-adrenergic blockers
3. Cholinergic agents
4. opioids Codeine is the most commonly used cough suppressant but is not indicated in asthmatic patients
Clinical Uses:
• Acute treatment of congestion associated with colds, sinusitis, allergies, etc.
• Frequently marketed in combination with antihistamines, cough suppressants,
expectorants, and analgesics/antipyretics
Decongestants: Phenylephrine and pseudoephedrine
Adverse Effects:
• Topical – rhinitis medicamentosa
• Oral – nervousness, agitation, insomnia, dizziness are common(approx. 25%)
• dry mouth,
• Oral – hypertension – de novo or worsening of existing – can be severe
Decongestants: Phenylephrine and pseudoephedrine
Mechanism:
Block action of histamine released from mast cells
• Competitive H1 receptor blocker, negligible H2 activity
• ……………………. agents also have
• significant anti-muscarinic /anticholinergic
activity (drying of secretions in the airways and the
sedative effect.)
1st generation – diphenhydramine, chlorpheniramine,
triprolidine
Clinical Uses:
• Allergic rhinitis – histamine primary mediator, mainstay of therapy
• Motion sickness
• Anti-emetic
• Sedation
1st generation – diphenhydramine, chlorpheniramine,
triprolidine
Adverse Effects:
– Sedation
– Impairment of motor skills
– Paradoxical stimulation: in infants and children, paradoxical CNS excitation, with symptoms of irritability, hyperactivity may occur.
1st generation – diphenhydramine, chlorpheniramine,
triprolidine
