Pharmacology - Respiratory Flashcards
Bronchodilators
Beta-agonists
Short acting 2-4hrs – Salbutamol, terbutaline
Long acting 12-18hrs – Salmeterol, formoterol
Indications: Asthma and other reversible airway obstruction + premature labour
MOA: Bronchodilators –> Selective B2 agonists act on bronchi to cause SM relaxation and decrease mucus production
S/E’s: Fine tremor, headache, muscle cramps, tachhycardia, palpitations, hypokalaemia (high doses)
CI’s: Caution in hyperthyroidism, CVS disease, arrhythmias, HTN, DM (risk of DKA when given IV)
Interactions: Hypokalaemia in high doses and with corticosteroids, diuretics, theophylline.
Other: Salbutamol = ventolin (reliever, short acting, fast onset, can be given IV in acute asthma) Terbutaline = bricanyl (ditto)
Salmeterol = serevent (preventer, long acting 12-18hrs)
Bronchodilators
Muscarinic Antagonists
Short acting 3-6hrs – Ipatropium
Long acting – Tiotropium
Indications: Reversible airways obstruction esp COPD
MOA: Bronchodilators - Anti-muscarinic –> block muscarinic ACh receptors in the SM of bronchi causing bronchodilation and decreased mucus secretion
S/E’s: Dry mouth, constipation, blurry vision, urinary retention
CI’s: Prostatic hypertrophy, bladder outflow obstruction, closed angle glaucoma
Interactions: -
Other: Ipatropium = atrovent (reliever, short acting)
Tiotropium = spiriva (preventer, long acting)
Beclometasone (Becotide)
Budesonide (Pulmicort)
Fluticasone (Flixotide)
Symbicort (Budesonide + Formoterol)
Seretide (Fluticasone + Salmeterol)
Inhaled corticosteroids
Indications: Reversible and irreversible airways disease e.g asthma/COPD
MOA: Corticosteroids –> act over weeks to decrease inflammation by decreasing cytokine production, prostaglandin/leukotriene synthesis, IgE secretion + leukocyte recruitment. Prevent long term decreases in lung function.
S/E’s: Inhaled = oral candidiasis, Long term use = OP, high dose can have system s/e’s, Oral use = systemic s/e’s
CI’s: Can cause paradoxical bronchospasm so use B2 agonist first
Interactions:-
Other: Take 12/52 to reach maximum effect. Decreased risk of complications if use a spacer device and rinse mouth after use. Fluticasone 2x as potent therefore use lower doses!
Symbicort = budesonide + formeterol (preventer and reliever in one as formoterol has fast onset)
Seretide = fluticasone + salmeterol
Theophylline MR
Aminophylline IV only
Indications: Reversible airways obstruction, severe asthma
MOA: Methylxanthines –> are phosphodiesterase inhibitors therefore increase cAMP, activates PKA, inhibits TNFalpha + leukotriene synthesis–> decreases inflammation and causes SM bronchodilation
S/E’s: Nausea, vomiting, arrhythmias, seizures, hypokalaemia
CI’s: Caution if arrhythmias/heart disease, HTN, hyperthyroid, PUD, lower dose in hepatic impairment
Interactions: Decreased levels in smoking, ETOH, Cyp inducers, adenosine. Increased levels with CCB’s, Cyp inhibitors.
Other: Aminophylline given only IV (give slowly, if too fast –> VT). Monitor ECG + bloods (K etc) + plasma level
Montelukast
Zafirlukast
Indications: Prophylaxis of asthma (esp exercise and NSAID induced)
MOA: Leukotriene receptor antagonist –> blocks the action of leukotriene on the cysteinyl leukotriene receptor –> decreases bronchoconstriction and inflammation
S/E’s: Abdo pain, thirst, headache, GI disturbance, ?Churg-Strauss syndrome
CI’s: Pregnancy
Interactions:
Other:
Roflumilast
Indications: Adjunct to bronchodilators for the maintenance of severe COPD assoc with chronic bronchitis and hx of frequent exacerbations
MOA: Phosphodiesterase type 4 inhibitor –> anti inflammation
S/E’s: D/V/N, abdo pain, weight loss
CI’s: Severe immunological disease, severe acute infectious disease, immunosuppresive drugs, pregnancy, depression/suicide hx
Interactions: Rifampicin –> inhibts effects
Other:
Omalizumab
Indications: Prophylaxis of allergic asthma (severe)
MOA: Humanised anti IgE Ab –> specifically binds to free IgE (IgE type 1 hypersensitivity reactions)
S/E’s: Abdo pain, headache, pyrexia
CI’s: Caution in autoimmune diseases, hepatic/renal impairment, pregnancy
Interactions:
Other: Sub cut injection every 2-4weeks
Carbocysteine
Indications: Reduction in sputum viscosity e.g. COPD, chronic productive cough, CF
MOA: Mucolytic
S/E’s: GI bleeding (rare)
CI’s: Active peptic ulceration, pregnancy
Interactions:
Other:
Dornase ALPFA (DNase)
Indications: Management of CF pts with a FVC of >40% predicted – improves pulmonary function
MOA: Mucolytic –> is a genetically engineered version of human DNase
S/E’s: Rarely dyspepsia, chest pain, dysphonia
CI’s:
Interactions:
Other:
Cetirizine
Loratidine/Clarityn
Fexofenadine
(Non sedating)
Chlorphenamine/Piriton (Sedating)
Indications: Symptomatic relief of allergies e.g. hayfever
MOA: Anti-histamines – selective H1R antagonists
S/E’s: Hypotension, arrhythmias (Increases QT/palpitations), anti AchM effects, drowsiness
CI’s: Severe liver disease, Caution in BPH/urinary retention, closed angle glaucoma, long QT syndrome
Interactions:
Other:
Treatment of Chronic Asthma
General - Inhaler technique, avoid allergens/triggers, stop smoking, monitor PEF (diary), pt education re compliance/attack management/specialist nurse etc
Medical
- SABA PRN (if used >1/d or nocte symptons then step
- Low dose inhaled steroid e.g. beclametasone 100-400 micrograms BD (usually start on 200)
- LABA e.g. salmeterol 50micrograms BD –> if a good response continue. If control still poor increase steroid to 400ug BD. If no benefit discontinue and increase steroid dose.
- If still poor control –> Trial of leukotriene receptor antagonist or theophylline (MR) or Bagonist PO or steroid dose 1000ug BD
- Oral steroids : Prednisolone 5-10mg OD (refer to specialist), use lowest dose possible to control symptoms
Treatment of chronic COPD
Assess Severity:
Mild = FEV1 >80%, FEV/FVC <0.7 + symptoms
Moderate = FEV1 50-79%
Severe = FEV1 30-49%
Very severe = FEV1 <30%
General - stop smoking/nicotine replacement/support progs, exercise, pulmonary rehab, lose weight, good nutrition, screen and tx other comorbidities, influenza/pneumococcal vaccines
Mucolytics - consider if chronic productive cough e.g carbocisteine
SOB +/- exercise limitation - SABA + SAMA (ipatropium) PRN
Exacerbations/SOB - LABA or LAMA + ICS
Persistent exacerbations - LABA + LAMA + ICS + roflumikast/theophylline, consider home nebs
LTOT - aim for PaO2 > 8 for 15hr/day (increases survival by 50%)
Surgery - Lung volume reduction sx
