Pharmacology Flashcards
What is pharmacodynamics?
What the drug does to the body
-Affinity
-Efficacy
-Potency
What is pharmacokinetics
What the body does to the drug (ADME)
- Absorption
- Distribution
- Metabolism
- Excretion
What is drug affinity?
The capacity for a drug to bind to a receptor
What is drug efficacy?
The maximum effect a drug can have win the body
What is drug potency?
How much drug is needed to elicit a response in the body
What is the mechanism of an agonist drug?
Attaches to and stimulate receptor
What is the mechanism of a competitive inhibitor?
Block receptor site
What is the mechanism of a non-competitive inhibitor?
alters receptor action site to prevent binding by binding at a site different to the action site
What is bioavailability?
The proportion of the drug given that enters circulation and can exert effect on body
What is first pass metabolism?
reduction of drug concentration due to metabolism by the body, especially the liver
State the main routes of administration of drugs and properties
- Oral - first pass metabolism
- IV - directly into systemic circulation
- Subcutaneous - has to diffuse through subcutaneous fat; absorbs slowly
- Intramuscular - Muscle = high vascularity so rapid absorption
- Topical - Directly onto skin/mucosa. Avoids first pass metabolism, slow absorption into circulation
- Rectal - Used when patient unable to tolerate oral route. Highly vascular so rapid absorption
- Intrathecal (into spinal column) - Direct access to CSF
- Sublingual/buccal (under the tongue) - Avoids first pass metabolism, rapid circ. absorption
- Inhalation - Effective if lung is target site
What is the function of eGFR and CrCl
Test of kidney function
What is CrCl?
Volume of blood plasma cleared of creatinine per unit time. Used to estimate GFR. Done by comparing serum creatinine vs urine creatinine.
Why is kidney function relevant when prescribing drugs?
- Most drugs excreted by kidneys
- Impaired kidney function –> reduced renal excretion of drug
- Drug concentration builds up –> toxicity and possible further renal impairment
Give examples of conditions where drugs would need to be adjusted to account for impaired kidney function
- CKD
- AKI
- Diabetes
- HTN (hypertension)
- Polycystic kidney disease
What does the Beta1 receptor act on and how?
- Heart - increased CO
- Kidneys - increased renin
What does the Beta2 receptor act on and how?
-Smooth muscle relaxation
1. Lungs - expansion
2. Blood vessels - dilated
3. GI tract - Peristaltic digestion decrease
4. Bladder - Urination decrease
5. Uterus - relaxation of uterine muscles
6. Liver - glycogenolysis; glucose released from liver to muscle
What does the Beta3 receptor act on and how?
- Adipose tissue - lipolysis and thermogenesis
- Bladder - decrease urination
What does the Alpha1 receptor act on and how?
-smooth muscle contraction
1. Blood vessels - contract
2. Pupils - dilate
3. Pylorus - contract
4. Urinary sphincter - contract
5. Prostate - contract
What does Alpha2 receptor act on and how?
-inhibitory
1. Presynaptic nerve terminals - inhibition
What receptors does the sympathetic NS act on?
- Alpha 1
- Alpha 2
- Beta 1
- Beta 2
- Beta 3
What receptors does the parasympathetic NS act on?
Muscarinic receptors
What are the 3 main types of diuretics?
- Loop diuretics
- Thiazide diuretics
- K+ sparing diuretics
How do loop diuretics work?
- Inhibit Na+/K+/Cl- cotransporters
- Normally all 3 ions absorbed, drawing water back into vasculature
- Blocked –> less water reabsorbed
How do you thiazide diuretics work?
- Inhibit Na+/Cl- contransporter in DCT
- Less Na+ reabsorbed –> less water follows
How do K+ sparing diuretics work?
- Inhibit reabsorption of Na+ and water in ENaC channels in DCT
- Leads to Na+ and water excretion and K+ retention
Give examples of loop diuretics
- Furosemide
- Bumetanide
Give examples of thiazide diuretics
- Bendroflumethiazide
- Indapamide
Give examples of K+ sparing diuretics
- Amiloride
- Spironolactone - aldosterone antagonist but has same effect; blocking aldosterone –> ENaC blocked
Outline the mechanism of action of NSAIDs
1.Cyclooxygenase (COX) inhibitors –> Prevents production of prostoglandins (vasodilator)
2. COX-2 inhibition is useful, COX-1 inhibition causes adverse effects
Outline the mechanisms of action of antihistamines
- H1 receptor antagonist
- Prevents release of histamine from storage granules in mast cells
Outline the mechanisms of action of Proton Pump Inhibitor (PPI)
Irreversibly inhibits H+/K+-ATPase pump in gastric parietal cells to reduce proton secretion
Outline the mechanisms of action of opioids
Activation of muscarinic receptors in CNS
What is a common side effect of NSAIDS?
- GI upset
- GI bleed
- Renal impairment
What is a common side effect of Anti-histamines?
- Older ones can cross BBB and cause sedation
- H1 receptors present in vomiting centre; can act as anti-emetics too.
What is a common side effect of ACE-inhibitor drugs?
- Dry cough due to bradykinin as it induces sensitisation of airway sensory nerves
- Dilates afferent glomerular arteriole; worsens kidney function
What is a common side effect of PPI?
Prolonged use in elderly leads to increased risk of fracture due to decreased calcium absorption –> osteoporosis
What is a common side effect of opioids?
- Respiratory depression –> GIVE NALOXONE
- Nausea and vomiting
- Constipation
- Tolerance and withdrawal
What is a common side effect of diuretics?
- Spironolactone can cause hyperkalemia (K+ sparing)
- Increased frequency of urination
- Dehydration
What is the difference between side effects and adverse drug reactions?
- Side effects = expected reaction
- Adverse drug reactions = unexpected
What is the Yellow Card reporting scheme?
Allows reporting of all adverse drug reactions
Outline UMS of Alendronate/alendronic acid
USE - treat osteoporosis
MECHANISM
1. Bisphosphonate adsorbed onto hydroxyapatite crystals in bone
2. Slows rate if growth and dissolution
3. reduces rate of bone turnover
SIDE EFFECT
1. D&V
2. Electrolyte imbalance
3. Change in ability to taste food
Outline UMS of Atenolol
USE - treat hypertension and arrhythmia
MECHANISM - beta 1 blocker
SIDE EFFECTS
1. Bradycardia
2. Peripheral coldness
3. Lethargy
Outline UMS of Atracurium
USE - neuromuscular blockade for surgery and mechanical ventilation
MECHANISM - Blocking the action of Ach on skeletal muscles
SIDE EFFECTS
1. Flushing
2. Hypotension
3. Bronchospasm
Outline UMS of Bendroflumethiazide
USE - treat hypertension
MECHANISM - thiazide diuretic
SIDE EFFECTS
1. D&V
2. ED
3. Fatigue
Outline UMS of Cephuroxime
USE - antibacterial
MECHANISM
1. attach to penicillin binding protein
2. Interrupts cell wall biosynthesis
3. Bacteria death
SIDE EFFECTS
1. D&V
2. Thrombocytopenia
Outline UMS of Celecoxib
USE - COX-2 inhibitor; treat pain and inflammation in osteoarthritis and rheumatoid arthritis
MECHANISM - SELECTIVE INHIBITION OF COX-2
SIDE EFFECTS
1. Gas/bloating
2. Constipation
3. Flu like symptoms
Outline UMS of Chloramphenicol
USE - antibiotic, used for eye infections
MECHANISM - Inhibit microbial protein synthesis by binding to microbial ribosome
SIDE EFFECTS
1. Stinging
2. Burning sensation
3. Irritation
Outline UMS of Ciclosporin
USE
1. treat pain in rheumatoid arthirtis
2. Prevent rejection of transplanted organ
MECHANISM
Inhibit synthesis of interleukins which are used for self-activation of T lymphocytes
SIDE EFFECTS
1. High BP
2. Increased hair growth
3. Swollen gums
Outline UMS of Ciprofloxacin
USE - Treat many serious infectious bacterial diseases such as
1. Pneumonia
2. Typhoid
3. Gonorrhea
MECHANISM - bacterial topoisomerase inhibitor
SIDE EFFECTS
1. D&V
2. Stomach pain
3. Lethargy
Outline UMS of Co-amoxiclav
USE - antibiotic
MECHANISM
1. Amoxicillin + clavulanic acid
2. Acid prevents bateria breaking down amox
3. Amoxicillin works like penicillin; bind to penicillin-bnding proteins to prevent cell wall synthesis
SIDE EFFECTS
1. D&V
2. Thrush
Outline UMS of Diamorphine
USE
1. Analgesia
2. MI
3. Respiratory sedative
MECHANISM OF ACTION
1. mu-opiod agonist
2. Acts on mu-opioid receptors in CNS & PNS
SIDE EFFECTS
1. Sweating
2. N&V
3. Constipation
Outline UMS of Dalteparin
USE - anticoagulant
MECHANISM OF ACTION
1. Increase activity of antithrombin III
2. Thus formation of factor Xa and thrombin prevented
SIDE EFFECTS
1. Excessive bleeding
2. Diarrhoea
3. Jaundice
Outline UMS of Dobutamine
USE - short term cardiac stimulant to increase contractility; manage low BP
MECHANISM OF ACTION
1. Stimulate beta-1 receptors in the heart
2. Increase myocardial contractility
3. Increased CO
SIDE EFFECTS
1. Dyspnea (shortness of breath)
2. Chest pain
3. Rapid weight gain
Outline UMS of Doxazosin
USE
1. Treat hypertension
2. Reduce symptoms of enlarged prostate
MECHANISM OF ACTION
1. Alpha-1 receptor blocker
2. decreases peripheral vascular resistance; BP decreased
SIDE EFFECTS
1. Oedema in peripheries
2. UTI
3. Headaches
Outline UMS of Ephedrine
USE
1. Treat hypotension during anesthesia
2. Bronchial asthma
MECHANISM OF ACTION
1. Alpha1, beta1 and beta2 adrenergic receptors agonist
2. Increased stimulation of sympathetic nervous system
SIDE EFFECTS
1. Blurred vision
2. Arrhytmia
3. Nausea
Outline UMS of Erythromycin
USE - antibiotic
MECHANISM OF ACTION
1. Protein synthesis inhibition
2. Bind to bacterial ribosome
SIDE EFFECTS
1. D&V
2. Loss of appetite
Outline UMS oof Ethinylestradiol
USE
1. Oestrogen deficiency
2. Menstrual disorders
3. Prostate cancer
4. Contraception
MECHANISM OF ACTION
1. Synthetic estrogen
2. Decreases LH –> prevent ovulation
SIDE EFFECTS
1. Peripheral oedema
2. N&V
3. Weight change
Outline UMS of furosemide
USE - treat hypertension
MECHANISM OF ACTION - loop diuretic
SIDE EFFECTS
1. Dry mouth
2. N&V
3. Headaches
Outline UMS of Ipratropium
USE - Bronchodilator; COPD symptom control
MECHANISM OF ACTION
1. Ach antagonist via block of muscarinic cholinergic receptor
2. Inhibit parasympathetic nervous system; decreased smooth muscle contraction in lungs
SIDE EFFECTS
1. Bladder pain
2. Painful urination
3. Dry mouth
Outline UMS of Loperamide
USE - treat diarrhoea
MECHANISM OF ACTION
1. Acts on mu-opiod receptor in intestinal muscle
2. Inhibits release of Ach and prostoglandins; propulsive peristalsis reduced, intenstinal transit time increased
3. Stimulate intestinal water absorption
SIDE EFFECTS
1. Constipation
2. Dizzy
Outline UMS of Metformin
USE - Type II diabetes
MECHANISM OF ACTION
1. Decrease hepatic glucosneogenesis
2. Decrease Intestinal absorption of glucose
SIDE EFFECTS
1. D&V
2. Loss of appetite
Outline UMS of methotrexate
USE
1. Treat cancer
2. Rheumatoid arthiritis
MECHANISM OF ACTION
1. Inhibit enzymes responsible for nucleotide synthesis; prevents cell division
SIDE EFFECTS
1. D&V
2. Mouth ulcers
3. Hair loss
outline UMS of Oxybutynin
USE - treat overactive bladder
MECHANISM OF ACTION
1. relax bladder
2. Inhibit muscarinic action of Ach on smooth muscle
SIDE EFFECTS
1. D&V
2. Dry mouth
3. Vertigo
Outline UMS of Paracetamol
USE - analgesiac and antipyretic
MECHANISM OF ACTION - COX inhibitor –> prosoglandins synthesis reduced –> pain relief
SIDE EFFECTS
1. Allergic reaction
Outline UMS of Ramipril
USE - treat hypertension
MECHANISM OF ACTION
1. ACE inhibitor
2. Inhibit RAAS system
3. Prevent angiotensin I to II conversion
SIDE EFFECTS
1. D&V
2. Headaches
3. Dry cough
Outline UMS of Rifampicin
USE - antibiotic to treat TB
MECHANISM OF ACTION
1. Inhibition of DNA dependent RNA polymerase
2. RNA synthesis supression
SIDE EFFECTS
1. Temporary discoloration of skin
2. Drowsiness
3. Vertigo
Outline UMS of Rivaroxaban
USE - Treat and prevent DVT
MECHANISM OF ACTION
1. Anticoagulant that finds directly to factor Xa
2. Blocks coagulation cascade amplification
SIDE EFFECTS
1. Bleeding
2. Lethargy
3. N&V
Outline UMS of Salmeterol
USE - Control symptoms of asthma and prevent bronchospasms
MECHANISM OF ACTION
1. Beta2 adrenoreceptor agonist
2. Causes bronchorelaxation
SIDE EFFECTS
1. Dry mouth
2. D&V
3. Trembling
Outline UMS of Sildenafil
USE - treat ED
MECHANISM OF ACTION
Increased blood flow to penis by enhancing effect of NO on corpus cavernosum
SIDE EFFECTS
1. Stuffy nose
2. Nausea
3. Headache
Outline UMS of Suxamethonium
USE - anaesthesia for intubation and mechanical ventilation
MECHANISM OF ACTION
1. Skeletal muscle relaxant
2. Mimics Ach at neuromuscular junction, but slowed hydrolysis
3. Results in prolonged depolarisation by blockade
4. Results in skeletal muscle paralysis
SIDE EFFECTS
1. Myalgia
2. Arrhytmia
3. Hyperthermia
Outline UMS for Tamsulosin
USE - treat enlarged prostate
MECHANISM OF ACTION
1. Alpha1 adrenoreceptoor blocker
2. Relaxes smooth muscle in prostate
SIDE EFFECTS
1. Back pain
2. Flu like symptoms
3. Sleeping difficulties
Outline UMS of Tramadol
USE - Opioid analgesiac
MECHANISM OF ACTION
1. mu-receptor agonist
2. SNRI (serotonin/norepinepherine reuptake-inhibitor)
SIDE EFFECTS
1. Dry mouth
2. Sweating
3. Constipation
