Drugs & Drug Delivery In Asthma & COPD Flashcards
Function of Theophylline/Aminophylline
Phosphodiesterase inhibitor
Bronchodilation
May have additive effects when used in conjunction w/ small doses of Beta2-agonists
Clearance is increased by smoking + reduced in heart failure, liver disease + COPD
Drug interactions
Monitoring
Brands - different brands have different rate of absorptions
Function of a leukotriene receptor antagonist
e.g. Montelukast
Block leukotrienes effects
Function of long-acting Beta2-agonists (LABA)
e.g. Salmeterol, formoterol
Same mode of action + adverse effects of SABA Works within 15-40 min
Effects last > 12 hours
Why are inhalers not used correctly?
Inhaler design
Individual patient factors
Lack of education - does HCP know how to use device correctly?
Disadvantages of dry powder inhaler
Work poorly if inhalation is not powerful enough
Need to prime dose each time
Most are moisture sensitive
Why is inhaler design a problem
patient cannot use device
patient may have different device
Advantage of pMDI
Compact
Portable
Multidose delivery
Suitable for emergency
When can inhaler devices be prescribed to the patient
Only after patients have received training in the use of the device and have demonstrated satisfactory technique
Generic prescribing avoided = lead to people with asthma being given an unfamiliar inhaler device which they are not able to use properly
Factors that increase levels of Aminophylline
Cimetidine
Ciprofloxacin
Macrolides
Oral contraceptive
Viral infection
Heart failure
Cirrhosis
Elderly
What is Haleraid?
Improves grip - patients with dexterity problems
Helps with compliance
Requires coordination
Types of inhalers
Pressurised metered dose inhaler (pMDI)
Dry powder inhaler (DPI)
Adverse effects of Corticosteroids
Oropharyngeal candidiasis
Adrenal suppression
Osteoporosis
Growth suppression
Pneumonia
Glaucoma
Benefits of Aminophylline
Failure to respond to other treatments
Not effective in exacerbations if COPD
Individual patients w/ near fatal or life-threatening asthma + a poor response to initial therapy may gain additional benefit
Function of long-acting muscarinic antagonist (LAMA)
e.g. Tiotropium, Aclidinium
Patients who remain breathless despite short-acting bronchodilators
Works within 1-2 hrs
Lasts for 24 hrs
Adverse effects of LTRA
Churg-Strauss syndrome
Hepatic disorders
Adverse effects of Aminophylline
Tachycardia
Palpitations
Nausea + vomiting
Headache
Insomnia
Arrhythmias
Same for theophylline
Drug interactions + narrow therapeutic window
Disadvantages of pMDI
Requires co-ordination
High oropharyngeal drug deposition
Function of Magnesium sulphate
Relaxes smooth muscle
Weak bronchodilator
Prescribe - 1.2-2 grams by IV infusion over 20 min
Aimed for patients who have acute severe but poor response to inhaled bronchodilators or life threatening asthma
Side effects of LAMA
Same as SAMA
Dry mouth
Blurred vision
Constipation
Nausea
Urinary retention
Tachycardia
Disadvantages of breath-actuated MDI
Require sufficient inspiratory flow to trigger device
Function of short-acting Beta2-agonists (SABA)
e.g. Salbutamol, Terbutaline
Relax smooth muscle + bronchodilate
Reduce breathlessness
Reliever/rescue medicines
Work quickly - effective withn 5 min + last for 4-6 hours
Do not control/prevent inflammation
Factors that decrease level of Aminophylline
Carbamazepine
Phenytoin
Rifampicin
St John’s Wort
Smoking
Chronic alcoholism
Advantages of Dry powder DPI
Breath actuated
Less coordination required
Compact
Portable
Higher lung deposition than pMDI
Side effects of SAMA
Dry mouth
Blurred vision
Constipation
Nausea
Urinary retention
Tachycardia
Combination products
Combining inhaled steroid + LABA E.g. Seretide® Fluticasone and salmeterol
Function of short-acting muscarinic antagonist (SAMA)
e.g. Ipratropium
Antagonise acetylcholine-mediated contribution to bronchospasm
Reliever = smooth muscle relaxation
Works within 30-40 min
Last for 3-6 hrs
Advantage of Breath-actuated MDI
Help to overcome coordination problems
Do not require coordination of device and inhalation
Function of Corticosteroids
e. g. Beclometasone, Budesonide, Fluticasone (inhaled)
e. g. Prednisolone (oral)
Reduce airway inflammation
Regular use reduces exacerbations
Discuss Nebulisers
A nebuliser converts a solution of a drug into a fine spray. You then breathe in the spray.
For patients with disabling breathlessness despite maximum therapy w/ inhalers
Suitable for severe acute asthma
Used in hospital
Low efficiency
Susceptible to microbiological contamination
Glaucoma risk w/ nebulised ipratropium
Why is indivdual patient factors a problem
Pulmonary function
Ability to remember correct method
What are Spacers?
Remove the need for coordination
Improve drug delivery
Reduce risk of oral infection from inhaled steroids
- steroid doesn’t deposit in mouth
Suitable for managing mild/moderate acute asthma/COPD
In children, pMDI + spacer are preferred for delivery of Beta2-agonists + inhaled corticosteroids
- face mask required until child can breathe using the spacer mouthpiece
