Drugs Flashcards
B2 agonists act by
relaxation of smooth muscle and enhance mucociliary clearance
Salbutamol
SABA
SABA
Short-acting Beta-agonist
Terbutaline
SABA
LABA
Long-acting Beta-agonist
Salmeterol
LABA
Formoterol
LABA
Name 6 Beta-2 agonists ADRs
- fine tremor
- nervous tension
- headache
- peripheral vasodilation
- tachycardia
- hypokalaemia
Corticosteroids - place in treatment?
2nd line preventers
How do corticosteroids work?
Anti-inflammatory, reducing bronchial hyper-response
Suppress inflammatory process
ICS are available in combination with..
LABA
Beclomethasone
ICS
Budesonide
ICS
Ciclesonide
ICS
Prednisolone class dose
Oral corticosteroid
dose: 40-50mg of 5/7 for acute attack
When are corticosteroids indicated? (4)
- exacerbation of asthma in last 2 years
- using inhaled B2-agonist >3 times/week
- symptomatic >3 times/week
- waking 1 night per week
ICS ADRs (3) and how to help with them
- hoarseness or dysphonia (use spacer/dry powder)
- oral candidiasis (rinse mouth after use/spacer)
- adrenal suppression BUT only in sustained doses >1500mcg of bethlamethosone daily
Oral corticosteroids ADRs (7)
Guidance on when to take
-Hypertension
-osteoporosis
-skin thinning
-hyperglycaemia
-adrenal suppression
-moon face
-acne
For oral corticosteroids: use lowest dose that will control symptoms for the shortest time possible
How do leukotriene antagonists work?
Where is their place in therapy?
anatagonise bronchoconstriction, airway oedema and mucous production
3rd/4th line controller/preventer therapy
oral montelukast
leukotriene antagonist
oral zafirlukast
leukotriene antagonist
ADRs of leukotriene antagonists(5)
- abdominal pain
- headache
- thirst
- rash
- sleep distrubance/CNS effects
Cromones mechanism of action
mast cell stabilisers, inhibits mediator (histamine) release from mast cells
Nedocromil
Cromone
Preventer in 5-12 year olds
ADRs of cromones (3)
- N&V (nausea and vomiting)
- bitter taste
- dyspepsia
Immunosuppresants for asthma treatment
Steroid-sparing agents
specialist use- rare
Gold for asthma
immunosuppresant
Methotrexate for asthma
immunosuppresant
Ciclosporin for asthma
immunosuppresant
how do methylxanthines work?
Where is their place in treatment of asthma?
phosphodiesterase inhibitors that inhibit leukotriene synthesis and thus inhibit inflammation and bronchodilation
3rd/4th line controller/preventer therapy
oral theophylline for asthma
methylxanthine
IV/oral aminophylline
methylxanthine
aminophylline is a salt of theophylline
Downside of methylxanthines (3)
How can you reduce these downsides (2)
Narrow therapeutic index ADRs Interactions reduce downsides by -using slow release preparations to give a more predictable effect -brand of drug must be kept constant
Methylxanthine therapeutic range
10-20mg/L
ADRs of methylanthines according to blood levels:
- <20mg/L - nausea, diarrhoea, nervousness, headache
- > 20mg/L - vomiting, insomnia, arrthymias
- > 35mg/L - hyperglycaemia, arrthymias, convulsions, death
what is clearance of methylxanthines affected by?
CYP450 metabolism
Effects of decrease clearance of methylxanthines
-Decreased clearance means increased plasma levels
-CCF (congestive heart failure)
-liver disease
-obesity
Note: dose is by ideal body weight (IBW)
drug interactions with methylxanthines that can lead to toxicity due to decreased clearance
enzyme inhibitors e.g.
- cimetidine
- erythromycin
- allopurinol
- ciprofloxacin
drug interactions with methylxanthines that can lead to reduced clearance and hence a sub-therapeutic effect
enzyme induction e.g.
- carbamazipine
- rifampicin
- phenytoin
- smoking
Omalizumab drug class and how it works
Anti-IgE monoclonal antibodies
inhibits binding of IgE to mast cell receptors therefore preventing inflammatory response to trigger
what is Omalizumab licensed for?
Add-on therapy in adults and children over 12 years for severe persistent asthma
how is omalizumab given?
Who can initiate omalizumab treatment?
S/C injection every 2-4 weeks
only initiated by specialist centres
patients must fulfill specific criteria (NICE)
when is omalizumab treatment discontinued?
Discontinued after 16 weeks if inadequate response
How is magnesium sulphate used in the treatment of ashtma?
How does the drug work?
- considered in acute asthma if PEF>50%
- given as single dose IV
- smooth muscle relaxant, t cell and mast cell stabiliser
Dapaglifozin
SGLT2 Inhibitor drug
Licensed to treat type 2 diabetes
Antacids are for
are available how
advantages
- Neutralise acid – first choice for dyspepsia and mild symptoms of GORD (also alginates)
- sodium bicarbonate containing
- OTC in liquid and tablet formulations
- simple, cheap, effective
- liquid is better but less convenient and portable
Antacids dose
As required (PRN) QDS or more daily
Antacids side effects
- if contain magnesium - laxative effect
- if contain aluminium - constipation
- If contain calcium- rebound acid secretion and hypercalcaemia
When to avoid antacids?
-if on salt-restrictive diet Avoid drugs with sodium in when: -renal and cardiac conditions -pregnant -hypertension
Low Na+ definition
The words “low Na” after some preparations indicate less than 1mmol per tablet or 10mL dose
Antacids interactions
-may impair absorption of other drugs taken at the same time
-may damage enteric coating by raising the pH
Rarely:
-may affect pH-dependent renal excretion e.g. increase excretion with possible reduction in serum levels (aspirin and lithium for example)
H2 antagonists
(Histamine2 antagonists)
suffix and 4 examples
Where are they available
-tidine
-Cimetidine
-Ranitidine
-Nizatidine
-Famotidine
All available OTC in low doses
H2 antagonists
What do they do?
What conditions are they licensed for?
All heal duodenal and gastric ulcers at higher doses than available OTC Licensed for: -maintenance treatment -NSAID prophylaxis (stop them causing -reflux (less effective than PPIs) -GORD (but less effective than PPIs)
H2 antagonists interactions
CYTP450 systwm
Cimetidine (oldest) interacts with
-warfarin - inhibits metabolism ↑INR - potential to bleed
-phenytoin, carbamazpine, valporate - inhibits metabolism, ↑plasma concentrations
-theophylline - inhibits metabolism, ↑plasma concentrations
-sidenafil - ↑plasma concentrations
Rantidine less interactions
Side effects of H2 antagonists
but usually
- headache
- diarrhoea
- dizziness
- occasionally rashes
- altered LFTs
Ranitidine less side effects
Helicobacter pylori does what?
- causes persistent infection in gastroduodenal mucosa
- infection always causes gastritis
- patient may not be aware of infection
- Host cofactors are critical to the development of ulcers
- 73% of gastric cancers MAY be caused by H.pylori
How does H.pylori do it’s damage
- buries itself in epithelia/mucosa
- produces urease
- produces good environment to itself
- mucosal cell death can expose them to pepsin and stomach acid
H.pylori tests
-H.pylori produces and antibody response detectable in serum, saliva or urine (antigens in the stool)
-Urea breath test kits whereby patient swallows 13C-labelled urea solution.
Urease activity by the enzyme produces labelled CO2
-Mucosal biopsies taken at gastroscopy
Urease test, histopathology or culture
-High antibody titre in patient generally indicates active infection
Testing parameters
do nots
-Antibody tests cannot be used for follow up after eradication therapy
-These tests should not be performed within 4 weeks of treatment with antimicrobials
or
2 weeks with PPIs or anti-secretory drugs
H.pylori treatment aims
Treatments should be
- Simple
- Well-tolerated
- easy to comply with
- cost effective
Triple therapy to eradicate H.pylori
High eradication rates 7 days -Clarithromycin -PPI -metronidazole or amoxicillin
doses of antibiotics used in triple therapy
- Clarithromycin (always used) 500mg BD or if with metronidazole then 250mg BD
- Amoxicillin 1mg BD (not if penicillin sensitive)
- Metronidazole 400mg BD
Anti-secretory agents (gold standard is PPIs)
Name 5 PPIs and their doses
- Omeprazole 20mg BD
- Esomeprazole 20mg BD
- Lansoprazole
- Pantoprazole 40mg BD
- Rabeprazole 20mg BD
Omeprazole side effects
- Rash
- Diarrhoea
Counselling for H.pylori
-emphasise importance of completing the course
Interactions:
-clarithromycin and statins (stop taking statin)
-metronidazole and alcohol - nausea if taken with it
-penicillin allergic or not?
Eradication of H.pylori
- In cases of complicated ulceration, continue the antisecretory agent alone for a further 3 weeks to achieve healing
- symptoms after eradication suggest GORD (reflux problems) or ulcer
Key treatment recommendations for GORD
- Full dose PPI for 1-2 months
- If symptoms reoccur than lowest dose PPI with alginate to control symptoms
- Patients should be advised to step down PPI (dose reduction plus alginate) or Step-off PPI (stop treatment)
- Intermittent treatment may work
- Symptomatic relief continues with antacids and/or alginate therapy alone
GORD in pregnancy
- dietary and lifestyle changes - clothing, small meals frequently, not a lot of fluid
- antacid or alginate
- Ranitidine
- Omeprazole in severe or complicated conditions
GORD in infancy
- usually resolves by 12-18 months
- change frequency and volume of feed
- feed thickener or thicker formulation feed
- use an alginate instead of thickened feeds
- Lifestyle changes and alginate for older children
GORD in older children
- alginate and lifestyle changes
- H2-receptor antagonists then PPI
NSAID-associated ulcers
High risk
- 2nd major cause of PUD
- High risk if over 65 and/or patients with a history of PUD
PUD is
Peptic ulcer disease
NSAID-associated ulcers prevention/protection drug classes
PPI
H2-antagonists (duodenal) .e.g Ranitidine at twice the normal dose
Misoprostol
Why are NSAIDs a problem in PUD?
NSAIDS are gastric irritants
NSAIDs are prostaglandin inhibitors
Prostaglandins is important for maintenance of mucosal blood supply, production of ,mucus and bicarbonate by cells
What is Misoprostol
- A prostaglandin analogue
- PGE1 has antisecretory and cytoprotective effects
Uses of mioprostol
- promote ulcer healing
- prevent NSAID-induced ulcers
Misoprostol is used in combination with
-Diclofenac
-Naproxen
These are both NSAIDs
Misoprostol side effects
Contraindications
Diarrhoea
DO NOT USE IN PREGNANCY
avoid in ladies of child-bearing age
treatment of NSAID-associated ulcers
Assume H.pylori negative
- stop NSAID if possible - Ibuprofen has lowest effects
- PPIs
- H2 antagonists
- Misoprostol
Treatment of NSAID-associated ulcers if the NSAID is needed to continue
Combo preps
Options
- Treat with PPI and continue long term at same dose
- Treat with PPI and on healing switch to misoprostol
- Treat with PPI and switch NSAID to selective COX-2 inhibitor
- Combination preparations:
- naproxen/esomeprazole 500/20
- ketoprofen/omeprazole - 100/20 and 200/20
Lifestyle advice for PUD
- smoking cessation
- avoid foods that cause dispepsia ie
- -fatty, acidic, fried foods and chocolate
- -reduction or exclusion of alcohol and caffeine
- avoid eating late in the evening
- don’t go hungry as this stimulates gastric acid secretion
- reduce stress
- weight reduction
- raising the head of the bed (GORD) with block, not pillows
- wear loose clothing
GORD is
Gastro-oesphageal reflux disease
What is long-term PPI therapy associated with
increased risk of adverse effects:
- Achlorhydria - low gastric acid production is associated with increased risk of…
- gastric cancer
- H.pylori infection (especially the elderly)
- pneumonia
- Clostridium difficle infection
- bacterial overgrowth
- reduced calcium absorption leading to hip fracture
PPI OTC
Esomeprazole
GSL medicine
use for up to 2 weeks
Potential interaction between omeprazole/esomeprazole with clopidogrel
Clopidogrel prevents blood clots
-The potential interaction between omeprazole and clopidogrel involving effects on its metabolism via the CYP2C19 enzyme has received much attention; however the evidence that it results in any clinically significant changes in outcomes is minimal
Recommendations include using an alternative PPI or an H2 Antagonist
Fatty foods…
delay gastric emptying
irritant effect on mucosa
Spironolactone for liver
treatment of ascites
100-600mg OD
Aldosterone antagonist
Furosemide for liver
Ascites treatment
40-160mg OD
diuretic
Metolazone
diuretic used in cases of ascites that are unresponsive to 1st/2nd line treatment
Rare
