Pharmacology - respiratory and GI Flashcards
Classes of bronchodilators
B2 agonists,
antimuscarinics
theophylline
Name a type of mucolytics
Carbocisteine, N-acetylcysteine.
Example of anti-inflammatory drug classes for asthma
Steroids, phosphodiesterase-4 inhibitors.
Example of anti-fibrotics
Perfenidone
Asthma management
Short acting B-agonist such as Salbutamol 200 mg.
Add low dose inhaled steroid such as betclometasone.
Add either a long-acting B agonist (salmeterol) or increase dose of ICS.
Increase steroids or add leukotriene receptor antagonist.
Under specialist guidance, start oral corticosteroid therapy.
Adverse effects of salbutamol
Commonly muscle tremors and tachycardia,
Rarely hypokalaemia, esp with interactions e.g. high dose corticosteroidds or diuretics.
Treatment of COPD if FEV1 is less than 50% of predicted
Either long acting antimuscarinic bronchodilator or long acting Beta2 agonist with corticosteroid.
Adverse effects of beclometasone
Cough and oral candidiasis.
Example of leukotriene receptor antagonists
Montelukast
Zafirlukast
Action of leukotriene receptor antagonist
Prevent leukotriene mediated bronchoconstriction.
Treatment of allergic IgE mediated asthma
Omalizumab as an add on to optimised standard therapy.
Theophylline action
Inhibition of PDE, adenosine receptor blockade, inhibition of inflammatory cells
Example of a phosphodiesterase inhibitor
Methylxanthine.
Rofumilast
Treatment of COPD when FEV1 is 50% or more of predicted.
Either long acting antimuscarinic bronchodilator or long acting Beta2 agonist.
COPD treatment if unable to use inhaler
Oral theophylline
Mucolytic drug
Oxygen therapy.
Treatment of GORD
Lifestyle modifications
Stop exacerbating drugs
Acid neutralisation
Mechanical prevention
Methods of acid neutralisation
Antacids
Acid suppression with H2 blockers
Proton pump inhibitors
Prokinetics
Mechanisms of antacids
Direct neutralisation by Mg or aluminium salts.
Mechanism of actions on H2 antagonist
Competitively inhibit histamine actions at all H2 receptors.
Examples of H2 antagonists
Cimetidine, Ranitidine.
Examples of proton pump inhibitors
Omeprazole 20mg/day, Esomeprazole 40mg/day
Lansoprazole 30mg/day
Pantoprazole 40 mg/day
Prokinetics used in GORD
Metoclopramide, domperidone
Prokinetics used in GORD - mechanisms
Dopamine antagonists.
Treatment of peptic ulcer disease
Helicobacter Pylori eradication
A PPI, amoxicillin and clarithromycin or metronidazole. (unless penicillin allergic. Then no amoxicillin, and both the third options.
Other drugs include bismuth chelate, sucralfate ad misoprostol.
Antiemetic drug classes - 1 2 3
M1 antagonists
Histamine H1 antagonists
D2 antagonists
5 HT3 receptor antagonists
Anticholinergic M1 antagonists
Scopolamine
H1 receptor antagonists
Cyclizine, promethiazine.
5 HT3 receptor antagonists
Ondansetron, granisteron
Classes of laxatives
Osmotic
Bulk-forming
Softeners
Stimulant
Treatment of severe acute asthma: OBC
Oxygen
B2 agonist by large volume spacer or nebs
Corticosteroid
(aminophylline infusion if not on theophylline)
Treatment of IECOPD
Nebulised bronchodilators and oxygen
Aminophylline
Corticosteroids
Abx.
Treatment of opiate overdose
Naloxone
Treatment of paracetamol overdose
Acetylcysteine.
If severe organ damage escalate.
Overdose causing drowsiness, ataxia, slurred speech, coma, RESP DEPRESSION and hypotension. Vomiting if combined w alcohol
Benzodiazepine
Treatment of benzodiazepine overdose
Protects airway and monitor
Flumezenil if marked resp depression, but beware of seizures.
Severe organ damage signs in paracetamol overdose
INR > 3.0
ALT > 1000 U/L
Hypotensive
Increased serum creatinine.
What is seretide?
Fluticasone 250 mcg and Salmeterol 50 mc. An asthma treatment - steroids and LABA.
What is cetirizine used for and at what dosage?
Allergies. 10 mg OD for adults.
Recommended treatment for severe CAP, patient
Initially IV therapy.
Coamoxiclav
Erythromycin (or clarithromycin)
What local anaesthetics could you use for a pleural effusion drain?
Lidocaine and prilocaine have fast onset and actions last an hour.
Bupivacaine has slower onset but lasts longer.
Usual dose of 1% lidocaine for local anaesthesia
10-20 ml
What is it important to do when administering lidocaine.
Draw back plunger to ensure not in vascular compartment.
Toxic effects of local anaesthesia occur when serum levels get too high. What are the effects?
Feeling of inebriation, lightheadedness, sedation, circumoral paraesthesia and twitching.
Osteoporosis prophylaxis
Bisphosphonate such as alendronic acid.
Consider when on long term steroids.
GI side effects of bisphosphonates
Oesophageal ulceration. Stay upright for 1/2 hour, drink full glass of water with it.
How does paracetamol overdose cause hepatotoxicity?
Alternative pathways become saturated, so paracetamol metabolism is shifted to the CYP450 pathway. Large amounts of NAPQI are therefore produced. Endogenous glutathione is insufficient to deactivate the large amounts of NAPQI, so this causes hepatotoxicity.
How does acetylcysteine IV infusion prevent hepatotoxicity in paracetamol overdose?
It is a precursor to glutathione, increasing capacity to conjugate NAPQI
When would you use a reducing dose of prednisolone?
Short term: to reduce the durations of morbidity in IECOPD or acute flare of asthma.
Long term: suppress the immune system in IgE mediated asthma.
Why would you use a reducing dose of prednisolone in IECOPD or an acute flare of asthma.
Reduce risk of relapse caused by acute withdrawal.
Ensure minimum effective dose is given.
Why would you use a reducing dose of prednisolone in IgE mediated asthma
Prevent Addisonian effects if a patient is steroid-dependent
Discuss different ways of weaning prednisolone.
A normal wean-off; takes days.
A slow wean; pt will experience some adrenal suppression.
If prednisolone dose approaches 7.5 mg OD then weaning needs to be VERY slow.
Indications for bronchoscopy
Suspected carcinoma, slowly resolving pneumonia, pneumonia in the immunosuppressed and interstitial lung disease.
Diagnostic indications for bronchial lavage
suspected malignancy, pneumonia in immunosuppressed, suspected TB, interstitial lung disease.
Percutaneous needle biopsy is used for…
Peripheral lung and pleural lesions.
Transbronchial biopsy is used to diagnose…
Diffuse lung diseases.
At risk groups who should get pneumococcal vaccine
More than 65 years.
Chronic cardiac, hepatic, renal or resp patients
DM
Immunosuppressed
AIDS
CONTRAINDICATED in pregnancy or lactation.
Treatment for mild or moderate CAP
Amoxicilin or clarithromycin or doxycycline. If moderate, give former together.
Treatment for legionella pneumonia
fluoroquinolone with clarithromycin or rifampicin.
Treatment for chlamydophila pneumonia
Tetracycline
Treatment for HAP
Aminoglycoside and penicillin
Treatment for aspiration pneumonia
cephalosporin and metronidazole.
Treatment for staph pneumonia
flucloxacillin and rifampicin (if MRSA, consider vancomycin).
Treatment for mycoplasma pneumonia
Clarithromycin or doxycycline.
Complications of pneumonia: treating type 1 resp failure
High flow oxygen (60%). Careful in COPD patients. Transfer to ITU if not improving.
Complications of pneumonia: hypotension
Due to dehydration and vasodilation.
If systolic BP is less than 90, give IV fluid challenge. If BP does not rise, consider a central line and give IV fluids to maintain systolic BP above 90.
Complications of pneumonia: AF
Usually resolves with treatment of pneumonia. Sometimes B-blocker or digoxin is used to slow ventricular response rate in short term.
Complications of pneumonia: pleural effusion
Drainage only if large and symptomatic or infected.
Complications of pneumonia: empyema - qualities of aspirated pleural fluid
Yellow and turbid, with low pH and glucose, and high LDH.
Treatment of allergic bronchopulmonary aspergillosis
Prednisolone. Sometimes itraconazole with corticosteroids.
Treatment for aspergilloma
Surgical excision if symptomatic.
Invasive aspergillosis
Voriconazole
Asthma management
Short acting B2-agonist
Inhaled steroid
Long acting B2-agonist and increase steroid
Oral B2-agonist, leukotriene receptor antagoinst, oral theophylline or high dose steroids.
Oral steroids.
COPD treatment
B2-agonist and/or long acting muscarinic such as tiotropium.
Severe - add long acting B2 agonist and corticosteroids.
Acute respiratory distress syndrome - causes
Pneumonia, aspiration, inhalation, injury, vasculitis, contusion.
Shock, septicaemia, haemorrhage, multiple transfusions, DIC, and many others.
ARDS - clinical features
Cyanosis, tachypnoea, tachycardia, peripheral vasodilation, bilateral inspiratory crackles.
ARDS - investigations
FBC, U&Es, LFTs, amylase, clotting, CRP. (underlying cause).
Blood cultures, ABG.
CXR shows bilateral pleural infiltrates.
Pulmonary artery catheter to measure pulmonary cap wedge pressure.
ARDS - diagnostic criteria
Acute onset
CXR with bilateral infiltrates
Pulmonary cap wedge pressure less than 19mmHg or lack of CCF
Refractory hypoxaemia.
ARDS management
Admit to ITU - respiratory support e.g. mech ventilation, circulatory support, check for and treat sepsis, nutritional support.
Treat underlying cause.
PE treatment
LMW heparin; stop when INR is greater than 2.
Start warfarin.
For massive PE needing thrombolysis, use alteplase.
Vena caval filter only if recurrent on anti-coagulation.
Inhibitors of the P450 system include
antibiotics: ciprofloxacin, erythromycin isoniazid cimetidine, omeprazole amiodarone allopurinol imidazoles: ketoconazole, fluconazole SSRIs: fluoxetine, sertraline ritonavir sodium valproate acute alcohol intake quinupristin
Opioids should be used with caution in patients with chronic kidney disease. What is preferred?
Alfentanil, buprenorphine and fentanyl are preferred
Morphine breakthrough dose should be what proportion of daily dose?
1/6th
To convert from codeine to morphine, what do you divide by?
10
How much should you increase opioid dose if you need to increase it?
30-50%
Which antibiotic is a common cause of cholestasis?
Co-amoxiclav
Which antibiotic classes may atypical pneumonias not respond to?
Penicillins and cephalosporins.
When is IV magnesium sulphate useful?
In acute asthma
What antibiotic should you use for an animal bite?
Co-amoxiclav
Treatment for ulcerative colitis - inducing remission
treatment depends on the extent and severity of disease
rectal (topical) aminosalicylates or steroids: for distal colitis rectal mesalazine has been shown to be superior to rectal steroids and oral aminosalicylates
oral aminosalicylates
oral prednisolone is usually used second-line for patients who fail to respond to aminosalicylates. NICE recommend waiting around 4 weeks before deciding if first-line treatment has failed
severe colitis should be treated in hospital. Intravenous steroids are usually given first-line
Ulcerative colitis - maintaining remission
oral aminosalicylates e.g. mesalazine
azathioprine and mercaptopurine
methotrexate is not recommended for the management of UC (in contrast to Crohn’s disease)
there is some evidence that probiotics may prevent relapse in patients with mild to moderate disease
Which TB treatment inhibits the P450 system?
Isoniazid