GP Pharmacology Flashcards
B2-agonists (SABA, LABA) MOA
Smooth muscle relaxation
Improves airflow in constricted airways, reducing breathlessness
SABA (e.g. salbutamol) indications and dose
First-line relief of breathlessness in COPD and asthma
100-200 micrograms up to 4 times/day
1 puff = 100 micrograms
B2-agonist side effects
Tachycardia Palpitations Anxiety Tremor Muscle cramps (LABA)
LABA (e.g. salmeterol) indications
Chronic asthma, when ICS alone insufficient (must be given with ICS)
Second-line to reduce symptoms/exacerbations in COPD
B-2 agonists interactions
Beta blockers can reduce efficacy of SABA/LABA
SAMA (ipratropium bromide) indications
COPD = first line to reduce exacerbations
Asthma = in acute exacerbations to relieve breathlessness
LAMA (tiotropium bromide) indications
COPD = to prevent exacerbations if no features of asthma/steroid reversibility
Asthma = add to ICS and LABA therapy if 1+ exacerbation per year
Theophylline
Oral bronchodilator
For chronic, uncontrolled by other therapies asthma/COPD
Criteria for LTOT in COPD
O2 <92% on RA Pulmonary oedema Non-smoker Polycythaemia (secondary) Hypoxia/hypercapnia
ACEi MOA
Prevents conversion of angiotensin I to angiotensin II (vasoconstrictor)
Reduces PVR
Reduces aldosterone = Na+ and H20 excretion, lowering BP (can be beneficial to kidneys).
Contraindications of ACEi/ARBs
Renal artery stenosis
AKI
Pregnancy/breastfeeding
Side effects of ACEi
Hypotension = sit/lie down for first dose
Dry cough
Hyperkalaemia
RARE: angioedema/anaphylactoid reaction
Dose of ACEi (ramipril)
1.25-2.5mg OD
Increased up to 10mg (max daily dose)
ACEi/ARBs fist line for which HTN patients
ALL with T2DM
<55 and NOT black/caribbean
Calcium channel blocker indications
HTN
Angina
Calcium channel blocker MOA
Relax/dilate arterial smooth muscle by decreasing Ca2+ entry into vascular/cardiac cells (lowers BP)
Reduce myocardial contractility, reducing rate and myocardial oxygen demand (prevents angina)
Side effects of calcium channel blockers (e.g. amlodipine)
Ankle swelling, flushing, headaches, palpitations (vasodilation and compensatory tachycardia).
Calcium channel blockers for vasculature
Dihydropyridines (amlodipine/nifedipine)
HTN
Calcium channel blockers for the heart
Non-dihydropyridines (verapamil/diltiazem)
Rate limiting = Angina
Amlodipine contra-indications
Unstable angina (tachycardia induced by vasodilation can increase myocardial oxygen demand)
Aortic stenosis (can cause collapse
CCB first line for which HTN patients?
> 55
Black/Caribbean
Thiazide diuretics for HTN in which patients?
Add on when HTN not controlled by CCB + ACEi/ARB
When CCB unsuitable for HTN due to oedema/other features of HF
Examples of thiazide diuretics
Bendroflumethiazide
Indapamide
Side effects of thiazide diuretics
Hyponatraemia (prevention of Na+ reabsorption)
Hypokalemia causing cardiac arrythmias
Male impotence
Increase plasma glucose, LDL and triglycerides
Stage 4 Tx for HTN if K+ >4.5
alpha blocker/beta-blocker
Stage 4 Tx for HTN if K+ <4.5
Spironalactone (k+ sparing diuretic)
Beta-blocker indications
Coronary heart disease (angina)
Chronic heart failure (improves prognosis)
AF (reduce ventricular rate)
HTN (if other medications fail)
Beta-blocker MOA
Reduce force of heart contraction, reducing cardiac work and oxygen demand, relieving cardiac ischaemia (treat angina)
Prolong refractory period of AV node and terminate SVT (treat AF)
Reduce renal renin secretion (lowers BP)