Cardiac drugs Flashcards
Management for stable angina?
Sublingual GTN for acute attacks
1st line = atenolol or calcium channel blocker
Atenolol if have HF. Don’t combine verapamil + atenolol = complete heart block (ok with long-acting dihydropyridine i.e. nifidipine)
Aspirin
Statin
Amiodarone
Mechanism of action?
Prolongs the refractory period in all cardiac tissues
Also exhibits some Na, K, Ca channel blockade + mild anti-sympathetic action
Amiodarone
Uses and indications
Most effective anti-arhythmic
Atrial fibrillation - in recurrent AF - slows heart rate + acute reversion (not used in permanent AF)
Ventricular tachycardia
What angina drug can tolerance be developed to?
Non-modified released GTN i.e. isosorbide mononitrate
What common drugs can cause long QT syndrome?
Amiodarone Soltalol Class 1a antiarrythmics Erythromycin TCA (citalopram)
Anticoagulation
What is the normal INR and target (therapeutic) INR range?
Normal
Anticoagulation
How often should INR be tested when commencing warfarin?
Every 1-2 days in first week to determine the correct individual dose.
Once established monthly testing is adequate
Anticoagulation
What patients require ‘bridging’ anticoagulation pre-operatively?
What do you use for bridging?
High clotting risk patients
- Recent DVT
- Recent stroke
- Mechanical valve
- CHADsVASc score > or equal to 6
Usually clexane unless mechanical valve which needs IV heparin due to extreme risk of clot
Anticoagulation
What other anti-coagulation factors should be considered when STARTING warfarin?
Initially it has a pro-thrombotic effect due to decreased Protein C production
It has a long half-life so its effect takes some days to be established
Consider loading dose or bridging with S/C clexane or heparin if in hospital
Anticoagulation
Factors which INCREASE effect of warfarin?
Liver disease - decreased clotting factors
NSAIDs - anti platelet effect, displace warfarin from plasma albumin
Amiodarone, ciprofloxacin - interfers with its metabolism (P450 enzyme inhibitiors)
Cranberry juice
Alcohol (acute consumption)
Corticosteroids
Macrolides
Anticoagulation
Factors which DECREASE effect of warfarin
Green leafy vegetables (vit K) - don’t have to reduce, need a stable consumption
Chronic alcoholism
Vit K supplements
Barbituates
Side effects of amiodarone
TALES
Thyroid - hyper or hypo Arrhythmia - prolonged QT interval Liver dysfunction Eyes - corneal deposits Skin - grey discolouration
Gastro
What is the most common site for diverticular disease?
Sigmoid colon (left side)
Gastro
How can diverticular disease and diverticulitis be diagnosed?
Diverticulae usually found incidentally on colonoscopy
Barium enema can clarify if symptomatic (abdominal pain, altered bowel habit)
CT gold standard for confirmation of acute diverticulitis - can identify extent of disease + complications
Abdo XRAY can identify obstruction, free air or fistulae
Gastro
In the acute setting of diverticulitis what Ix should be avoided?
Barium enema and colonoscopy risk perforation
Gastro
What features on CT in acute diverticulitis?
Focal fat stranding adjacent to the diverticulae
May see extra-luminal fluid and gas locules
Bowel wall thickening
May see complications - fistulae, perforation, abscess
