DRUGS Flashcards
Pilocarpine
Muscarinic receptor agonist
Used to decrease intraocular pressure in glaucoma
Atropine
Muscarinic receptor antagonist
Uncharged - can cross BBB
Used by opthamologists to dilate pupils during retinal examination
Atropine methonitrate
Charged - confined to periphery
Hyoscine
Muscarinic receptor antagonist
Edrophonium
Acetylcholinesterase inhibitor
Short duration (5-10 minutes)
Acts on NMJ
Used in diagnosing Myasthenia Gravis
Neostigmine
Acetylcholinesterase inhibitor
Medium duration
Acts on NMJ
Used as oral treatment for Myasthenia gravis + to reverse effect of non-depolarising NMB
Physostigmine
Acetylcholinesterase inhibitor
Medium duration
Acts on parasympathetic ganglia
Used as eye drops for glaucoma + Alzheimer’s disease
Dyflos
Acetylcholinesterase inhibitor
Very long duration (irreversible)
Acts on postganglionic parasympathetic synapses
Organophosphate - highly toxic
Parathione
Acetylcholinesterase inhibitor
Very long duration (irreversible)
Acts on postganglionic parasympathetic synapses
Used as insecticide - commonly causes poisoning in humans
Suxamethonium
Nicotinic receptor agonist Acts on NMJ Phase I - prolonged depolarisation Phase II - desensitisation of receptor = muscle paralysis Used as a depolarising NMJ blocker
Chlorothiazide
Thiazide diuretic
Acts in distal tubule to block Na+/Cl- transporter
Increased Na+ in urine causes water movement into urine
More water excreted = decreased blood volume = decreased BP
Used in mild to moderate hypertension
Cilazopril
ACE inhibitor
Inhibits ACE enzyme prevents ATII production
No AT1 or AT2 receptor activation or aldosterone production = water excretion = decreased blood volume
Used for hypertension
Side effects:
- cough (bradykinin accumulation because ACE degrades bradykinin)
- angiodema
- hypotension
- rash
Losartan
ARB - Angiontensin Receptor Blockers
Blocks AT1 receptor = no pathological effects
Side effects: no bradykinin accumulation so no cough
- hypotension
Used for hypertension
GTN
Glyceryl Trinitrate Releases NO and causes vasodilation Used in acute attacks of angina Side effects: - reflex tachycardia - dizziness - headache - hypotension - flushing
Propranolol
Non-selective beta blocker Blocks B1 and B2 receptors in the heart, lungs, and kidney Used to treat hypertension (only in combination with others) Side effects: - fatigue - CNS effects - bronchoconstriction (asthmatics) - worsening lipid profile - hypoglycaemia (blocks glycogenolysis)
Atenolol
B1 selective beta blocker
Unable to cross BBB = no CNS effects
Doesn’t target B2 = no bronchoconstriction
Used in treatment of angina, hypertension (in combination not first line), arrythmias
Side effects:
- fatigue + reduced exercise tolerance
Metaprolol
B1 selective beta blocker
Able to cross BBB = CNS effects
Doesn’t target B2 = no bronchoconstriction
Used in treatment of angina, arrythmias, hypertension (in combination with other drugs, not first line)
Side effects:
- CNS effects
- fatigue + reduced exercise tolerance
Nifedipine
Vessel specific Calcium Channel Blocker (CCB)
Acts on resting channels = vessel specific
Blocks L-type calcium channels
Used in hypertension treatment of elderly patients (relieves vessel stiffness)
Side effects:
- hypotension
- facial flushing
- reflex tachycardia + increased work for heart (don’t use alone)
Verapamil + Diltiazem
Cardiac + vessel Calcium Channel Blockers (CCB)
Act on active channels
Block L-type calcium channels
Used in angina (increase oxygen supply to heart + reduce workload)
Also used in hypertension + arrhythmias
Side effects:
- hypotension
- flushing
- can cause cardiac depression if used with Beta blockers
Aspirin
Antiplatelet
Irreversibly binds COX enzyme
COX1 produces TXA2 - platelet chemotaxic agents = inhibited = reduced platelet recruitment = reduced clot formation
Low dose = portal circulation and minimal COX2 inhibition
Used to reduce risk of clot formation
Side effects:
- gastric bleeding
Heparin
Anticoagulant Increases ATIII (antithrombin III) activity + binding to Factor Xa, prothombin and thrombin Inhibits clot formation Used in MI or stroke, DVT Side effects: haemorrhage Antagonist = protamine sulfate
Warfarin
Anticoagulant Prevents Vitamin K reduction (involved in prothrombin formation) = prevents fibrin formation Used for MI or stroke, DVT etc. Side effects: - haemorrhage - bruising - Low TI - drug interaction (CYP450) Reversal therapy: - Vitamin K administration - fresh frozen plasma containing clotting factors - prothrombinex-VF
Alteplase
recombinant tissue plasminogen activator (rt-PA) = fibrinolytic
converts plasminogen to plasmin = breaks down the clot
Used for MI or stroke (short time frame use)
Side effects: bleeding
Aspirin
NSAID Irreversibly binds COX enzyme Inhibits COX2 inflammatory effects but also COX1 gastroprotective effects Used for treatment of inflammatory pain Side effects: GI effects + bleeding
Indomethacin
NSAID
More COX1 selective
Anti-inflammatory
More adverse effects due to COX1 selectivity
Ibuprofen
NSAID
analgesic and anti-inflammatory
Fewer side effects
Diclofenac
NSAID
more potent than indomethacin
Analgesic for inflammatory pain
Adverse effects = GI and headaches
Paracetamol
Analgesic + antipyretic but no anti-inflammatory
Side effects:
- liver toxicity
- no GI effects
Celecoxib
COX2 inhibitor
Has cardiac risk
Morphine
Opioid High efficacy Mimics endogenous opioids (enkephalins) and acts on mu receptors = pain inhibitory system Used for acute and chronic pain Side effects: - euphoria - respiratory depression - decreased GI motility (constipation) - opioid dependence
Codeine
Opioid Low efficacy - slow release = no euphoria Used for acute and chronic pain Side effects: - decreased GI motility - respiratory depression
Methadone
Opioid High efficacy Used for reduction of heroin addiction Side effects: - decreased GI motility - respiratory depression
Fentanyl
Opioid High efficacy Used for high powered pain relief Side effects: - decreased GI motility - respiratory depression
What are the treatment options for asthma?
Preventers
- corticosteroid e.g. inhaled fluticasone + oral prednisolone
- leukotriene receptor blockers
- B agonists LABA: salmeterol and SABA: salbutamol
Tubocararine
Non-depolarising NMB
Can be reversed by acetylcholinesterase inhibitor e.g. neostigmine
Suxamethonium
Depolarising NMB
Diazepam
Spasmolytic - relax overactive muscles
Acts on GABAa receptor (inhibitory neuron)
CNS
Used as a sleeping pill
Baclofen
Spasmolytic - relax overactive muscles
Acts on GABAb receptors (inhibitor metabotropic)
CNS
Dantrolene
Spasmolytic - relax overactive muscles
Acts in periphery - reduces release of calcium from internal muscle cell stores
Botox
Spasmolytic - relax overactive muscles
Acts in periphery - cut up SNARE proteins required for the release of ACh vesicles
Used in cosmetics and to relieve painful muscle spasms such as Cervical Dystonia (head and neck)
Levodopa (L-dopa)
Metabolic precursor of dopamine
Given with dopa decarboxylase (Carbidopa) to prevent conversion to dopamine in the periphery = goes to the brain for conversion (dopamine can’t cross BBB)
Used as first line treatment for Parkinson’s Disease
Problems:
- hallucinations + delusions
- dyskinesia
- on-off phenomenon (sudden, unpredictable movements)
- decreased effectiveness due to cell death
Apomorphine
Dopamine agonist
Used in combination with L-dopa to smooth off on-off phenomenon
Less effective but lasts longer and less risk of dyskinesia
Given as sc injection
Used as second line treatment for Parkinson’s disease
Side effects:
- nausea/vomiting
- hallucinations
- dopamine + reward system = compulsive shoppers or gamblers
Enzyme inhibitors for PD
MAO inhibitor
- Used in early stages
- Helpful for treating anti-depressant effects in later stages
COMT inhibitor
both can be used in combination with L-dopa to increase its effectiveness
Last line of treatment
Haloperidol
Typical antipsychotic (1st gen)
Dopamine type 2 receptor antagonist or inverse agonist
Used in the treatment of Schizophrenia postive symptoms (hallucinations + delusions)
Side effects:
- Parkinson-like effects due to decreased dopamine in nigrastriatal pathway
- induces negative side effects due to decreased dopamine in prefrontal cortex
- wide spread side effects because affects other receptors in the body (muscarinic, histamine, alpha adrenergic)
Clozapine
Atypical antipsychotic (2nd gen)
Interacts with D1 and D2 dopamine receptor types + blocks serotonin receptors (involved in increased dopamine activity)
Less affinity for other receptors = less side effects that 1st gen
Side effects:
- less risk of Parkinson-like effects due to decreased dopamine in nigrastriatal pathway
- less side effects due to muscarinic, histamine, alpha adrenergic receptor binding in rest of body
More commonly used than 1st gen for the treatment of Schizophrenia positive symptoms
Diazepam and alprazolam
Benzodiazepines Positive Allosteric Modulators of GABAa receptors Benefits: - fast acting = no therapeutic delay - large TI (safe in overdose) - effective antagonist: Flumazenil
Diazepam has a long duration (24-48 hours) and used for short term relief of anxiety
Alprazolam is medium duration and used for anxiety and depression
Side effects:
- drowsiness, confusion, amnesia, impaired coordination
- can produce substantial impairment in everyday life
problems:
- problems in elderly due to accumulation (long plasma half-life)
- tolerance: receptor desensitisation
- dependence: withdrawal symptoms if stopped suddenly = increased anxiety
first line treatment for acute anxiety (short term use <4 weeks)
Buspirone
partial agonist of 5HT (serotonin) receptors
only clinically approved drug of its class for the treatment of anxiety
side effects:
- dizziness, headache, nervousness, light-headedness, nausea
- side effects subside over time or with decreased dose
safer long-term than BZDs:
- no withdrawal symptoms
- no tolerance or dependence
- non-sedating so safer in overdose
second line treatment if antidepressants don’t work (only for GAD)
Antidepressants
SSRIs (selective serotonin receptor inhibitor) and SNRIs (selective noradrenaline receptor inhibitor)
Also tricyclic antidepressants (TCAs)
More neurotransmitter in synapse = more binding to receptor
Side effects:
- anxiety, insomnia, fatigue, nausea, dizziness, palpitations
- withdrawal syndrome with sudden discontinuation (milder than with BZD)
side effects and therapeutic lag can be overcome with adjunctive BZD use for first 1-2 weeks
first line treatment for chronic anxiety because wide range of effectiveness over many anxiety disorder types
Halothane + Nitrous oxide
Gaseous anaesthetics
Maintenance of anaesthesia
1 - once induced administer gaseous anaesthetic at MAC
- more lipid soluble = more potent
- some gases act in synergy = both lower than MAC
Kinetics of anaesthesia
- water solubility
high water solubility = slow delivery to CNS lipids
low water solubility = fast delivery to CNS lipids - rate of ventilation
high rate = more efficient gas delivery - partial pressure of gas
high concentration = increased delivery - cardiac output
high HR = high CO = more deliver to brain
Thiopental
Barbiturate = IV anaesthetic
highly lipid soluble = fast onset + short duration
Side effects:
- reduced CO
- hypotension
- respiratory depression
- reduced cerebral blood flow and O2 distribution
Ketamines
IV anaesthetic Disconnects thalamus from cortex = sensations to thalamus not processed by patient Very lipid soluble = fast onset + short duration Side effects: - amnesia - analgesia - rigidity - catatonia - disorientation + hallucinations
Lignocaine + Bupivacaine
Local anaesthetic
Blocks VSSCs from inside the cell especially small diameter pain fibres (no myelin) = no depolarisation
Use dependence (little goes via non-use-dependence pathway)
Features of ‘ideal local anaesthetic’:
- selective blockage of sensation
- rapid onset + rapid reversibility
- non-toxic systemically and locally
Treatment for type 1 diabetes?
administer insulin
rapid acting: Novorapid
short acting: Actrapid
long acting: Humulin NPH
What are the treatment plans for type 1 Diabetes?
Minimum choice protocol:
- strict diet and exercise
- no compensation for cheating
- little flexibility
- minimal decision-making
- good blood glucose stability + minimal risk of hypoglycaemia
Tight protocol:
- patient wants to be proactive and self-managing
- maintain optimal blood glucose levels
- consists of 2 parts: maintain basal levels + adjustments for meals
- patient continuously monitors and adjusts
- greater chance of hypoglycaemia
Metaprolol
1st line treatment for type 2 diabetes
Effects:
- reduced glucose absorption in GIT
- reduced gluconeogenesis in liver
- increased insulin receptor sensitivity due to reduction in plasma insulin levels
= increased glucose uptake + decreased hyperglycaemia
Side effects:
- diarrhoea + abdominal discomfort
- contraindicated for patients with renal disease = accumulation + increased toxicity
- lactic acidosis = lactate buildup in muscles
Antacids
Weak bases that neutralise acids to form salt and water
e.g. CaCO3, Mg(OH)2, Al2(OH)3
Used in mild cases of GORD - doesnt prevent over-production of acid
Adverse effects:
- excessive use of calcium salts = kidney stones
- aluminium + calcium = constipation
- magnesium = diarrhoea
- calcium carbonate = produces gas and belching
Cimetidine
Histamine (H2) antagonists
H2 is GsPCR and causes increased gastric acid secretion
Used in treatment of mild peptic ulcer + mild GORD
Adverse effects: (usually minor)
- headache
- dizziness
- diarrhoea
- muscular pain
- abrupt withdrawal = transient increase in gastric acid secretion = relapse of peptic ulcer/GORD
Omeprazole
Proton Pump Inhibitor
Covalently binds to proton pump (H+/K+ ATPase)
= reduced basal and stimulated acid secretion
Used as 1st line treatment for moderate to severe GORD or peptic ulcer (drug of choice for mild to severe gastric acid related disorders)
Benefit of PPIs:
- prolonged duration due to covalent binding
- short plasma half-life
Adverse effects:
- headache
- abdominal pain
- nausea
- caution in patients with hepatic disease because drug extensively metabolised
- interferes with absorption of drugs that require acidic environment
Chlorhexidine
Antiseptic
Binds to -ve phosphates on lipid membrane on exterior of cells
Prevents adherence and causes lysis at higher concentrations
Specificity: targets all bacteria + affects our cells as well
Penicillin-G
Beta lactam
Binds to PBP (penicillin binding protein) on transpeptidase which is involved in peptidoglycan cross-linking
Bacteriocidal = creates holes in cell wall
Specificity: gram +ve bacteria
Low TI because human cells do not produce peptidoglycan
Gentamicin
Aminoglycoside
Irreversibly binds to 30S subunit of bacterial ribosome
Specificity: gram +ve and gram -ve bacteria (not anaerobes as oxygen required in drug transport)
low TI because some people have mitochondiral ribosomes that are very similar to bacteria = more susceptible to cell damage
