Respiratory drugs Flashcards
Drugs that cause bronchospasm
- Non-selective beta blockers
- Histamine releasing drugs
- Cholinomimetics
- Morphine (histamine release + vagal tone)
- Prostaglandin F2 alpha (constriction of uterus, blood vessels and bronchi)
Treatment of atopic/extrinsic/allergic asthma
Omalizumab - binds to IgE prevents binding to IgE receptor and mast cell degranulation
Bronchodilators
Big Mike Makes The Coffee
B2 adrenoreceptors
Muscarinic 3 blockers
Methylxanthine Theophylline
Cysteinyl leukotrienes
B2 receptor agonists
Selective
1. SABA. salbutamol + terbutaline
2. LABA - salmetorol + formeterol
Non-selective
Aie
1. Adrenaline
2. Isoprenaline
3. Ephedrine
Adverse effects of B2 adrenoreceptor agonists
TTTH
1. Tachycardia and arrhythmia (direct acts on b1 and indirect vasodilation of skeletal muscles decreases BP)
2. Tremor
3. Tolerance
4. Hypokalemia (potassium shift)
Why are B2 agonists not used for children?
B2 receptors are not fully developed
Muscarinic blockers
- Atropine
- Ipratropium
Passive weak bronchodilation
Must be used with B2 agonist
Why is atrophine not used for asthma treatment?
- Nonselective
زغلوله الناشفه حبست جوزها ابو سريعه - Tertiary amide - can cross BBB
SAD HC
Sedation
Amnesia
Delirium
Hallucination
Coma
What is used as a substitute for atropine?
Ipratropium for COPD
1. More selective
2. Quaternary amide
3. Does not cause excessive dryness
Methylxanthines
Natural
1. Theophylline
2. Caffeine
3. Theobromine
Semi-synthetic
1. Aminophylline injectable
Mechanism of action of methylxanthines
- Block adenosine 1 receptors (bronchodilation, decreased mucus secretion, CNS stimulation, block histamine release and tachycardia increase AV conduction)
- Inhibit PDE 3 and 4
PDE 5 inhibitor - sildenafil Viagra
↑ cAMP - bronchodilation and vasodilation (relaxation of smooth muscle) and ↑ cardiac muscle contractility (+ve inotropic)
↑ CGMP - NO release vasodilation EXCEPT brain vasoconstriction
Effects of methylxanthine
- Smooth muscle relaxation (bronchodilation and vasodilation)
- Cardiac muscle contraction (+ve inotropic)
- Vasoconstriction of cerebral blood vessels - migraine
Uses of methylxanthine
Respiratory
1. Acute - slow infusion aminophylline AA
2. Chronic - SR theophylline or aminophylline rectal suppository
CNS
1. Hypnotic overdose (CNS stimulant)
2. Delay physical and mental fatigue
3. Migraine - methylxanthine + ergotamine (alpha 1 agonist) + sumatriptan
↑ ergotamine absorption + synergism
4. Neonatal apnea syndrome (caffeine sulphate)
CVS
Pulmonary edema due to acute left sided HF
Adverse effect of methylxanthine
CNS - insomnia, nervousness, tremors, headache, seizures
CVS - tachycardia
Rapid IV injection - syncope, hypotension and cardiac arrest
GIT - ↑ HCL secretion
Methylxanthine contraindications
- Peptic ulcers - increases HCL
- Arrythmia - tachycardia
- Renal, hepatic or pulmonary disorders
Methylxanthine drug interactions
Microsomal enzyme inhibitors
1. Cimetidine - peptic ulcer
2. Erythromycin
3. Zileuton - 5LOX inhibitor
Microsomal enzyme inducers
1. Smoking
2. Rifampin
Unless stop for duration of treatment or increase dosage
Anti-inflammatory drugs
Chronic
1. Oral prednisolone 20 mg
2. Oral dexamethasone 4-8 mg
3. Beclomethasone inhalation
Acute
1. Hydrocortisone IV 200mg every 4hrs if necessary
2. Dexamethasone (beclomethasone)
Adverse effects of anti inflammatory drugs
Oropharyngeal candidiasis
Take with anti fungal drugs amphotericin + nystatin AND mouthwash
Anti-inflammatory pre-cations
- Gradual withdrawal to avoid acute adrenal crisis
- Diet rich in K+ and protein and low in NaCL and carbs
- Diuretics - edema and weigh gain
- Immunosuppressant therefore treat infections with antibiotic and reduce steroid dose
Prophylactic treatment
- Leukotriene inhibitors
- Montelukast x1 management of asthma in children
- Zafirulokast x2
LTD4 receptor blockers
- Zileuton (5 LOX inhibitor + microsomal enzyme inhibitor contraindicated in methylxanthine) - Mast cell stabilizers via chloride channels
- Nedocromil
- Cromolyn - sodium cromoglycate (not absorbed from diet) - Ketofien - 2nd gen antihistamine + mast cell stabilizer
Other drugs
- Expectorants and mucolytics
- Heliox
- Omalizumab
Management of cough
- Specific - underlying cause
- Non-specific - symptomatic
- Dry cough antitussive
- Wet cough mucolytic and expectorant
Antitussives
Peripheral
1. Water vapor with methanol or benzoin tincture
2. Benzonatate - glycerol dervivative of procaine local anesthetic effect
Central
1. Opioids codeine and hydrocodone - lower dose than that that causes analgesic effect
2. Synthetic opioid L isomers dextromethorphan
Mucolytics
- Bromhexine - formation of mucus breaks mucopolyschharide fibers
- Ambroxol - increases surfactant production
- N-acetylcysteine and carbocyseine - add H+ to disulfide bonds between glycoproteins breaking them apart
Expectorants
- Potassium iodide - increases proteolytic enzyme effect
- Guaifenesin
- Others
- Ammonium chloride
- Tincture ipecacuanha
- Herbal remedies
In emergency department the preferred first line of asthma therapy is
B2 agonist
