Pharmacology Flashcards
MOA of Pilocarpine? (Indication: Glaucoma)
Stimulation of muscarinic cholinergic receptors to increase aqueous humour outflow resulting in ciliary contraction (contraction of the iris), which will increase aqueous humour outflow, miosis, and accommodation.
MOA Latanoprost? (Indication Glaucoma)
Increasing uveoscleral outflow of aqueous humour by activating prostaglandin receptors
MOA: Dorzolamide? (Indication glaucoma)
Reduce the production of aqueous humour by inhibition of carbonic anhydrase
Mechanism of Aspirin?
irreversibly inhibits cyclooxygenase-1 (COX-1) enzyme which inhibits the production of thromboxane A2
MOA of Ciclosporin and Tacrolimus?
inhibit calcineurin thus decreasing IL-2
MOA Fleclanide?
potent sodium channel blocker (specifically the Nav1.5 sodium channels
MOA of LMWH?
Low-molecular weight heparin activates antithrombin III. Forms a complex that inhibits factor Xa
Digoxin:
MOI?
Indications?
Notable SEs?
inhibition of the Na+/K+ ATPase pump (Slows rate via AV and positive inotropic affect)
Rate control, symptoms in HF (specific indications)
SE = arrythmias, confusion, yellow/green vision, gynaecomastia
INDUCERS of cytochrome P450 (PC BRASS)
Phenytoin, Carbamazepine, Barbiturates, Rifampicin, Alcohol (chronic), Sulphonylurea, Smoking,
Inhibitors of cytochrome P450 (CRACK AMIGOS)
Cimetidine, Ritonavir, Amiodarone, Ciprofloxacilin, Ketoconazole, Acute alcohol use, Macrolides, Isoniazid, Grapefruit juice, Omeprazole, Sulfonamides
MOI Pilocarpine?
Muscuranic Agonist
Pharmacokinetics: what is phase 1 metabolism?
oxidation - Addition of oxygen or removal of hydrogen atom
reduction - Gain of electrons or hydrogen atoms
hydrolysis - add water to a drug molecule resulting in its breakdown to more polarised forms
Pharmacokinetics: what is phase 2 metabolism? (Conjugation)
Products are typically inactive and excreted in urine or bile
What is first past metabolism?
a phenomenon where the concentration of a drug is greatly reduced before it reaches the systemic circulation due to hepatic metabolism. As a consequence much larger doses are need orally than if given by other routes
What is zero order kinetics?
describes metabolism which is independent of the concentration of the reactant. This is due to metabolic pathways becoming saturated resulting in a constant amount of drug being eliminated per unit time
T/F 50% UK population are deficient in Acetylator status which affects metabolism of key drugs?
True
Drugs affected:
isoniazid
procainamide
hydralazine
dapsone
sulfasalazine
Mnemonic for zero order kinetics:
Zero Alcohol Is Allowed
Police (Phenytoin)
Stop (Salicylate)
Heavy (Heparin)
Drinkers (Ethanol)
Mnemonic for drugs affected by acetylator status:
SHIPpeD
Sulfosalazine. Hydralazine. Isoniazid. Procainamide. Dapsone
Mnemonic for first past metabolism drugs:
Nitrates Have A Very Large Pre Systemic Intake
Nitrates, hydrocortisone, aspirin, verapamil, lignocaine, propranolol, iSoSorbide dinitrate, Isoprenaline, Testosterone
MOA of Quinolones (e.g. ciprofloxacilin)
Inhibits DNA synthesis by inhibiting topoisomerase
MOA Macrolides (e.g. Clarithromycin)
Binds to 50S subunit, inhibiting translocation (movement of tRNA from acceptor site to peptidyl site)
MOA of tetracyclines (e.g. doxycycline)
Binds to 30S subunit blocking binding of aminoacyl-tRNA
MOA Aminoglycosides? (Gentamicin)
Binds to 30S subunit causing misreading of mRNA
MOA of Penicilins, cephalosporins, carbapenems?
Inhibit the cross-linking of peptidoglycans in bacterial cell walls
MOA Metronidazole?
DNA Damage
MOA Sulphonamides, trimethoprim?
Inhibits folic acid formation
MOA Rifampicin?
Inhibits RNA synthesis
What drug is indicated, when you suspect adrenaline induced ischaemia during local infiltration?
Phentolamine (Competitive a-adrenoreceptor antagonist)
MOA Metformin?
activation of the AMP-activated protein kinase (AMPK)
Aetiology of heparin induced thrombocytopenia?
Antibodies against complexes of platelet factor 4 (PF4) and heparin
Monitoring blood test for:
1) Unrationed Heparin
2) LMWH
1) APTT
2) Anti-factor Xa
Infliximab:
Indication:
Target:
Crohns
TNFa
Rituximab
Indication:
Target:
Non-Hodgkins
CD20
Daratumumab
Indication:
Target:
Multiple Myeloma
CD38
Alemtuzumab
Indication:
Target:
chronic lymphocytic leukaemia
CD52
Trastuzumab (more commonly known as Herceptin)
Indication:
Target:
metastatic breast cancer
HER2
What is the mechanism of aminoglycoside neprhotoxicity?
Acute tubular necrosis
Pathophysiology of paracetamol induced hepatotoxicity?
Paracetamol overdose occurs when glutathione stores run-out leading to an increase in NAPQI (N-acetyl-p-benzoquinone imine)
T/F Ciprofloxacilin side effects -> everything is increased (Fluid, BP, K+, Hair, Gums, Glucose)
True
How does COCP use affect the incidence of the following cancers:
1) Breast + Cervical
2) Ovarian + Endometrial
1) Increased risk
2) Decreased risk
Drugs which can be cleared with Hemodialysis (BLAST)
BARBITURATE
Lithium
Alcohol (inc methanol, ethylene glycerol)
Salicylates
Theophyllines
MOA of heparin?
Enhances activity of circulating antithrombin
1mg of prednisone is equivalent to how much hydrocortisone?
4mg hydrocortisone
1mg Dexamethasone is equivalent to Hoe much prednisone?
7mg Prednisolone
How do class one anti arrhythmias work?
Inhibit sodium channels
-Amiodarone/ Lidocaine/ Phenytoin / Flecainide
How do class two anti arrhythmias work?
Beta blockers
-propranolol
-Esmolol
How do class 3 anti arrhythmias work?
Potassium Channel Blocker
-Sotalol
-Amiodarone
How do class 4 anti arrhythmias work?
Calcium channel blocker
-Verapamil
-Diltiazem
How do class 5 anti arrhythmias work?
Unexplained
-Adenosine / Digoxin / K+ ions / Mg Ions
MOA of furosemide?
(lasix)
Inhibiting chloride absorption in the ascending loop of Henle
(Lasix = lasts 6 hours)
MOA of Bendroflumethaizide?
Inhibiting sodium absorption at the beginning of the DCT
What is ‘DRESS’ syndrome?
Drug reaction with eosinophilia and systemic symptoms
-Triad: Extensive skin rash, pyrexia, organ involvement
Cyanide Poisoning
-Presentation
-Signs
-Pathophysiology of poisoning
-Tx:
-Factory worker rescued from fire (burning plastics)
-Headache, bitter smell, red, ashen, hypoxic
-Inhibition of cytochrome C Oxidase leading to cessation of mitochondrial electron transfer chain
-IV Hydroxocobalamin
(Alternatives: inhaled amyl nitrate / IV Sodium thiosulfate)
Where is the most common defect implicated in Catecholaminergic polymorphic ventricular tachycardia (VPVT)?
-Gene defect
-Inheritance pattern
-Ryanodine receptor (RYR2) found on myocardial sarcoplasmic reticulum
-Autosomal Dominant
Brugada Syndrome
-Inheritance pattern
-Gene mutation
-Autosomal dominant
-SCN5a which encodes the myocardial sodium ion channel protein
Congenital Cyanotic heart disease:
-Most common at birth
-Most common overall
-Transposition of the great arteries
-Fallots
4 most common congenital acyanotic heart diseases?
-VSD
-ASD
-PDA
-Coarctation of the aorta
Patient Ductus Arteriosus
-Acyanotic or cyanotic
-Where is the abnormal connection
-Management
-Acyanotic
-Pulmonary trunk and descending aorta
-Indomethacin
(However, may use prostaglandin E1 to keep open if awaiting surgical repair)
