Drugs Flashcards
Losartan
Angiotensin II Receptor Blocker/Antagonist
Indications:
Diabetic nephropathy in T2DM
Chronic heart failure when ACE inhibitors are unsuitable or contra-indicated
HTN
CI: eGFR < 60
Side Effects: Hyperkalaemia, postural hypotension
F/U: After starting patients on an ACE i, if there is a rise in creatinine by >100% or to above 310 umol/l, or if potassium rises to >5.5 mmol/l the ACE inhibitor should be stopped
Statins
TAKEN AT NIGHT!
MoA: inhibit the action of HMG-CoA reductase, the rate-limiting enzyme in hepatic cholesterol synthesis.
SE:
Myopathy, liver impairment, may increase the risk of intracerebral haemorrhage in patients who’ve previously had a stroke.
CI: Macrolides and pregnancy
Indication:
1) all with established cardiovascular disease (stroke, TIA, ischaemic heart disease, peripheral arterial disease)
2) 2014 update, NICE recommend anyone with a 10-year cardiovascular risk >= 10%
3) T2DM should now be assessed using QRISK2 like other patients are, to determine whether they should be started on statins
4) T1DM who were diagnosed > 10 years ago OR are >40y OR have established nephropathy
Dose:
atorvastatin 20mg for primary prevention
increase the dose if non-HDL has not reduced for >= 40%
atorvastatin 80mg for secondary prevention
Anti-emetic dosages
Ondansetron - 4mg tds
Metoclopramide - 10mg tds
CI in bowel obstruction (increases gastric motility) and Parkinsons (can exacerbate sx)
Cyclizine - 50mg 8hourly, NB this is an sedating anti-histamine
Domperidone - safer to use in parkinsons as even though its a dopamine antagonist, it doesn’t cross BBB
Anti-emetics same doses IV and oral
Neuropathic pain meds
Amitriptylline - 10mg o nightly
Pregabalin - 75mg o 12hourly
Duloxetine - 60mg OD (painful diabetes)
Verapamil
Verapamil is a rate-limiting CCB that can be used in the management of angina, however should never be used alongside a beta-blocker. This combination increases the risk of severe bradycardia and heart failure.
MOA: interfere with the inward displacement of Ca ions through the slow channels of active cell membranes in myocardial cells, slowing contractility and depressing electrical signals.
I: HTN, Tachycardias
CI: HF, AF and AFlutter, Bradycardia, hypotension
Diltiazem
Rate limiting CCB
MOA: interfere with the inward displacement of Ca ions through the slow channels of active cell membranes in myocardial cells, slowing contractility and depressing electrical signals.
I: Prophylaxis, Treatment of Angina, Anal fissure, Rate control in AF if pt has asthma as BB are a CI to those with asthma (adrenergic effect on the bronchioles)
ACEI MoA SE I CI
established 1st-line treatment in younger pts with HTN (less effective in treating HTN Afro-Caribbean pts)
I: HTN, HF, diabetic nephropathy and prophylaxis of ischaemic heart disease.
Moa: inhibit the conversion Ang I > Ang II
ACE inhibitors are activated by phase 1 metabolism in the liver
S/E:
- cough (occurs in around 15% of patients and may occur up to a year after starting treatment. Due to increased bradykinin levels, which would’ve been degraded by ACE)
- angioedema: may occur up yr after starting treatment
- hyperkalaemia
- first-dose hypotension: more common in patients taking diuretics
CI:
pregnancy and breastfeeding - avoid
renovascular disease - may result in renal impairment
aortic stenosis - may result in hypotension
hereditary of idiopathic angioedema
specialist advice should be sought before starting ACE inhibitors in patients with a potassium >= 5.0 mmol/L
What beta blockers block both beta and alpha blockers and why is this useful?
Carvedilol and labetalol block both alpha and beta 1 & 2
This is useful for to control BP in those with phaeo or cocaine OD
Betablockers
Alpha 1 blockers - prevent vasoconstriction and tachycardia decrease contractility (NA/A are agonists -> vasoconstriction, tachy and bronchodilation)
Beta 1 blockers slow down heart rate (1= heart)
Beta 2 blockers cause bronchoconstriction (2 = lungs) (CI in asthma)
Beta blockers than block 1>2’s name begins with the first half of the alphabet i.e. a-m (atenolol, betaxalol, esmolol, metoprolol). 2 & 1 nadolol, propranolol, timolol
Side effects: Mask hypoglycaemia by slowing the body down, erectile dysfunction, dyslipidemia esp with metoprolol, hypotension (orthostatic), fatigue (short term), bronchospasm (SOB/Wheeze)
Indications: Angina, SVT, HTN, Glaucoma, variceal bleed prophylaxis (propanolol), AF (relaxes atria), HF (carvedilol, bisoprolol and nebivalol only)
Other important things:
- metaprolol succinate = Sooo long, long acting version of metoprolol)
- NEVER STOP BETA BLOCKER SUDDENLY-> rebound tachycardia and HTN
- Nebivalol is special its B1 selective and cause vasodilation (reduces BP in 2 ways)
Aldosterone antagonists
MoA: Blocks aldosterone. Aldosterone causes Na+ Cl- reabsorption and K+ excretion in collecting duct.
Indications: 2nd line HF,
Side effects: gynaecomastia (esp sprionolactone), Hyperkalaemia,
Thiazide Diuretics
inhibiting sodium reabsorption at the beginning of the distal convoluted tubule (DCT) by blocking the thiazide-sensitive Na+-Cl− symporter. Potassium is lost as a result of more sodium reaching the collecting ducts. Thiazide diuretics have a role in the treatment of mild heart failure although loop diuretics are better for reducing overload. The main use of bendroflumethiazide was in the management of hypertension but recent NICE guidelines now recommend other thiazide-like diuretics such as indapamide and chlortalidone.
Common adverse effects
- dehydration
- postural hypotension
- hyponatraemia, hypokalaemia, hypercalcaemia*
- gout (reduces uric acid secretion)
- impaired glucose tolerance
- impotence
Rare adverse effects
- thrombocytopaenia
- agranulocytosis
- photosensitivity rash
- pancreatitis
Adenosine
MoA: Causes transient heart block in AV node. Agonist of A1 receptor and this inhibits the enzyme adenyl
ARB
Candarsetan, Losartan, Valsartan
Propofol
Most popular, only induction and maintenace drug that can be given IV
Rapid onset/offset
Hypotention Decrease RR, pain on injuection
Etomidate
Used in emergency, esp haemodynamically onsent,
Thiopentane
Barbiturate, replaced by porpofol
Rapid onset
Hangover reduced CO
Inahalation agents for
Sevoflurance
Isoflurance
How to avoid common pitfalls in prescribing
PReSCRIBE Patient details Reactions i.e. allergies Sign the front of the chart CI to each drug Route IV fluids Blood clot prophylaxis E - antiemetic
Patient is having haemoptysis, how do you alter their drug chart?
Drugs that increase the risk of bleeding (aspiring, heparin and warfarin) shouldn’t be given
Drugs that are enzyme inhibitors e.g. erythromycin can make warfarin more potent
Side effects of steroids
Stomach ulcers + indigestion Thin skin oEdema Right and left HF Osteoprosis Infection (esp candida) Diabetes (actually more hyperglycaemia than diabetes) Cushing's Syndrome
NSAIDs CI and cautions
No UO (Renal failure) (NSAIDs inhibit PG synthesis which reduces renal artery diameter and blood flow reducing kidney perfusion and function) Systolic dysfunction (HF) Asthma Indigestion (any cause) Dyscrasia (clotting abnormality)
Antihypertensives side effects
Categorise
1) Generalised - all antihypertensives can cause hypotension incl postural hypotension
2) More specific - Bradycardia (BB and CCB) and Electrolyte disturbance (ACEi and diuretics)
3) Very specific:
ACEi - dry cough
BB - wheeze in asthmatics
CCB - peripheral oedema and flushing
Loop diuretics - renal failure, gout
K+ sparing diuretics - renal failure, spiro can cause gynaeocomastia
When giving fluid replacement, when don’t we give saline?
- Hypernaraemic or hypoglycaemic (GIVE DEXTROSE 5%)
- Has Ascites (Human Albumin solution instead- due to oncotic pressure, saline will worsen ascites)
- Hypotensive (from blood loss -> blood t; septic with SBP <90, give a colloid e.g. gellofusine as it has a high osmotic content so stays intravascularly and maintains BP for longer)
Methotrexate
MoA: folate antagonist (inhibits the enzyme dihydrofolate reductase, essential for the synthesis of purines and pyrimidines.)
I: Crohn’s, Rheum, Psoriatic, Neoplasias
Cautions: Bone marrow toxicity, GI toxicity, liver toxicity, pulmonary toxicity
Use contraception for 6 months after stopping it, avoid in breast feeding
CI: other folate antagonists e.g. trimethoprim, anything that affects liver, GI or renal function
Causes of neutropenia
Viral infection
Chemotherapy or radiotherapy
Drugs:
Clozapine (antipsychotic) and Carbimazole (antithyroid)
Causes of SIADH:
Small cell lung tumours Infection Abscess Drugs esp carbamazepine and antipsychotics Head Injury
Causes of K+ derrangement
Hypokalaemia - DIRE Drugs (loop and thiazine diuretics) Inadequate intake or intestinal loss Renal tubular acidosis Endocrine (cushing's and conn's)
Hyperkalaemia - DREAD Drugs (ACEi, K+ sparing diuretics) Renal failure Endocrine (addisons) Artefact (due to clotted sample) DKA
Acute HF management
A-E
- furosemide: 40-160 mg/dose IV initially (not oral)
- GTN if SBP > 90
± Spiro (can be used in combo to offload
If patient is hypotensive i.e. haemodynamicall unstable give a ionotrope and a vasopressor e.g. dobutamine and dopamine
Drugs that have muscarinic side effects
BEN Needs AA Immediately
Bladder drugs - Oxybutynin, Tolterodine
Eye Drugs - Atropine, Hyoscine (buscopan)
Neuropathic med - Amitriptylline
Antidepressants - citalopram, fluoextine, venlaflaxine, olanzepine, amitriptylline, sertraline
Antihistamine - Cyclizine (antie-emetic)
Insomnia drugs - Zopiclone. trazodone
Antiplatelet and aspirin - can they be prescribed at the same time?
must be discussed with a specialist as the combo causes
a very high risk of bleeding. However, it is sometimes indicated.
Typically, if an antiplatelet and anticoagulant are prescribed concurrently, a DOAC with lowest GI bleed risk should be considered i.e. apixaban, and PPI cover should be added.
Severe Acute Asthma guidelines
Give a high-dose inhaled beta-2 agonist (e.g., salbutamol) administer by nebs driven by oxygen
Add nebulised ipratropium to beta-2 agonist treatment, via an oxygen-driven nebuliser
Give a corticosteroid as early as possible 50 mg o OD for at least 5 days
Consider single dose MgSO4 if PEF <50%
If life threatening -> admit to ICU and consider aminophylline
