Pharmacology Flashcards
What abx inhibit cell wall formation
Cephalosporins and penicillins
Which requires higher INR - mitral valves or aortic valves
mitral
how does Ivabradine work?
inhibits IF (funny) channels - mixed sodium and potassium channels…. so it delays depolarisation in the sinoatrial node and therefore selectively slows heart rate
Side effects of ivabradine
transient luminous phenomenon (reported by up to 15% of patients)
thiaze diuretics blood abnormalities
works by inhibiting sodium reabsorption… so hyponatraemia, hypokalaemia and hypercalcaemia (so also hypocalcuria so good for renal stones)!
SGLT2 inhibitors examples
-GIFLOZIN
canagliflozin, dapagliflozin and empagliflozin
SGLT2 inhibitor side effects
…secretes glucose in urine so:
genital infection (secondary to glycosuria)
diabetic ketoacidosis
WEIGHT LOSS
increased cholesterol - unclear if this affects mortality though
What is the mechanism of action of amphotericin B?
amphotericin b binds with ergosterol, a component in fungal cell membranes and forms pores that cause lysis of the cell wall and subsequent fungal cell death
mechanism of action of colchicine
bind to tubulins, thereby blocking the assembly and polymerization of microtubules
drugs that cause toxic epidermal necrolysis
phenytoin allopurinol sulphonamides penicillins carbomazepine NSAIDS
(lookslike scalded appearance over an extensive area,positive Nikolsky’s sign: the epidermis separates with mild lateral pressure)
most common cause of drug-induced angioedema
ACEi
TB meds side effects
rifamapacin - orange secretions, flu-like
Ethambutol - optic neuritis
Isonazid - peripheral neuropathy (prevent with pyridoxine (Vitamin B6)) and pellagra (b3 def)
Pyrazinamide - gout, arth/myalgia
What antibiotics exacerbate myasthenia gravis?
Gentamicin is worst, but also macrolides, tetracycline and metronidazole. Amoxicillin is ok
Sulphonylurea mechanism of action
Binds to and closes ATP-dependent K+(KATP) channel on the cell membrane of pancreatic beta cells…. Which simulates insulin release
Drugs that cause peripheral neuropathy
Nitrofurantoin, amiodarone, isoniazid, metronidazole, vincristine
How does Metformin work?
Increases insulin sensitivity, activates AMP-activated protein kinase
Mechanism of action of allopurinol
Inhibits xanthine oxidase, which creates 6-thiouric acid
Mechanism of action of bisphosphonates
Inhibits osteoclasts
Ando pain, frequency, haematuria, calcification on bladder….. Swimming in African lake. Antibiotic to treat schistosoma haematobium
Praziquantel
Mechanism of action of aspirin
Inhibits production of thromoxane a2
Mechanism of action of enoxaparin and fondaparinux
Activates antithrombin III, which potentiates the inhibition of coagulation factors Xa
Medication for old man with overactive bladder treatment or urge incontinence
Tolterodine or darifenacin (anti muscarinic). Anti muscarinics are contraindicated if history of retention though so use mirabegron (a beta-3 agonist)
- oxybutynin can cause confusion
Reversal agent of beta blocker
Atropine or IV glucagon
Reversal of benzodiazepines
Mostly managed with best supportive care but Flumazenil if servere (risk of seizures)
Methanol poisoning reversal agent
Fomepizole or ethanol
Haemochromatosis
Mechanism of action of methotrexate
Inhibits dihydrofolate reductase and thymidylate synthesis
What is acetylator status
50% of UK population lack hepatic n-acetyltransferase
What drugs are affected by acetylator status
Isoniazid, Procanamide Hydralazine Dapasone Sulfasalazine
Treatment for leprosy
rifampicin, dapsone and clofazimine for 12 month
Antibiotic to avoid in LQT
erythromycin
Antibiotic to avoid in LQT
erythromycin
Treatment for c diff in regular and in severe
Metronidazole PO 10-14 days
Severe then vanc and IV metronidazole
mecchanism of carbimazole
pro drug,,gets converted to methimazole, this prevents thyroid peroxidase from coupling and iodinating the tyrosine residues on thyroglobulin, hence reducing the production of the thyroid hormones T3 and T4
side effects of sulphonylureas eg tolbutamide
hypos and weight gain
avoid in preg and breast
acne vulgaris treatement in pregnancy
Acne vulgaris in pregnancy - use oral erythromycin if treatment needed
Mechanism of zoladex (goserelin)
GnRH agonist
Treatment of Lyme’s
Oral doxy but use IV ceftriaxone if disseminated CNS involvement.
Amoxi if pregnant, as doxy contraindicated
features and causes of Oculogyric crisis…
agitation, involuntary upward deviation of the eyes… antipsychotics and metoclopramide
Drug causes of lithium toxicity
Thiazides, ACEi, metronidazole and nsaids
Causes of drug induced lupus
Most common causes
procainamide
hydralazine
Less common causes
isoniazid
minocycline
phenytoin
HIPP Hydralazine Isonoazid Procainamide Phenytoin
Drug causes of c diff
clindamycin: RR = 31.8
cephalosporins: RR = 14.9
ciprofloxacin: RR = 5.0
Second Gen cephalosporins like cefuroxime is more likely to cause c diff than cefalexin
Where does thiazides affect
Inhibit sodium reabsorption in beginning of the distal convoluted tubule by blocking Na-Cl symporter
Drug that is associated with an increased risk of atypical stress fractures
Bisphosphonates. because, due to reduced bone turnover, the bone ages.. more prone to fracture
Drugs that cause 6 month history of dry cough and shortness of breath on exertion…
Pulmonary fibrosis is caused by Amiodarone Anti rheum drugs like methotrexate Nitrofurantoin ergot-derived dopamine receptor agonists (bromocriptine, cabergoline, pergolide)
Name live attenuated vaccines
Live attenuated vaccines
BCG
MMR
oral polio
yellow fever
oral typhoid
Mechanism of action of terbinafine
Terbinafine inhibits the fungal enzyme squalene epoxidase, causing cellular death
Turbines squaeel
Drug side effect of topiramate
drug-induced acute angle closure glaucoma, typically occurring within one month of treatment
P450 inducer too so worsening of contraceptive pill/implant
Foetal malformations
Drugs that affect levothyroxine
Iron, calcium carbonate, coffee
Drug that interacts with clopi
Omeprazole and esomeprazole
sulfasalazine cross reactivity
Patients who are allergic to aspirin may also react to sulfasalazine
SALA
p450 inducers
CRAP GPS induce rage
Carbamazepine Rifampicin (Reduces INR) bArbituates Phenytoin St Johns wort Grisiofalvin Phenobarbital Sulphonylurea, st John's wort
p450 inhibitors
Some Certain Silly Compounds Annoyingly Inhibit Enzymes, Grrrrrrr
Sodium valporate Ciprofloxacin Sulphonamide Cimetidine/omeprazole Antifungals, amiodarone Isoniazid (Increases INR) Erythromycin/clarithromycin Grapefruit juice
Side effects of isotretinoin
Dry eyes teratogenicity Nosebleeds Depression Hair thinning Raised triglycerides
Alcoholic comes in with persistent skin rash on his hands, arms, neck and face. The rash is red-brown in colour, symmetrical and scaly. He also complains of a poor appetite, nausea and diarrhoea…. What vitamin is he deficient in
Niacin (vit B3)
Pellagra is a caused by nicotinic acid (niacin) deficiency. The classical features are the 3 D’s -dermatitis, diarrhoea and dementia. Dermatits is brown scaly rash on sun-exposed sites (Casal’s necklace)
Isoniazid can trigger it
Patient with sore throat is treated then develops rash.
What antibiotic might he have been started on?
Amoxi.
Urti should be treated with treated with phenoxymethylpenicillin (pen V) because amoxi causes widespread erythematous rash in patients with infectious mononucleosis.
Purpose of desmopressin in Von Willebrand’s
desmopressin (DDAVP): raises levels of vWF by inducing release of vWF from Weibel-Palade bodies in endothelial cells
Anti malarial prophylaxis
atovaquone + proguanil (Malarone)
Mefloquine (Lariam, contraindicated in epilepsy)
doxycycline
Chloroquine (contraindicated in epilepsy, resistance in South East Asia)
Patient 75 NOF, what do you do to prevent further?
Treat with bisphosphonates…no need to wait for dexa
If not tolerated then strontium ranelate
Transient rise in Cr following UTI treated with trimethoprim
Competitively inhibits tubular secretion causing a temporary rise in creatinine.
Also interacts with methotrexate because both inhibit dihydrofolate reductase
What drugs are best for motion sickness
Hyoscine
Cyclizine (non sedating)
drug management of Alzheimer’s
Start on acetylcholesterase inhibitor (denepozil, galantamine and rivastigmine)
Second line is Memantine… so moderate alz you can add it in, or can use on it’s own in severe
Drugs to treat drug induced Parkinson’s
Anti muscarinic
Like procyclidine, benzotropine, trihexyphenidyl (benzhexol)
SE of ciclosporin
Ciclosporin side-effects: everything is increased - fluid, BP, K+, hair, gums, glucose
What can cycle does vincristine act on?
Metaphase
What is the toxic metabolite of Paracetamol
NAPQI (N-acetyl-p-benzoquinoneimine)
Bacterial static Vs ,-cidal
Core medical trainee (to) Specialist trainee.. mneumonic for bacteriostatic
Bacteriostatic: CORe - ChlORamphenicol Medical - Macro TRAinee - TeTRAcycline to SPecialty - SulPhonamide TRaInee - TRImethoprim
Treatment for Chlamydia paittaci - psittacosis
Doxy
Patient with IBD wants to pregnant, which meds are safe
Azathioprine, mesalazine and sulfasalazine (with folic acid) are safe to use in pregnancy and breastfeeding
Most dangerous tricyclic antidepressants in overdose
amitriptyline and dosulepin (dothiepin) are considered the most dangerous in overdose
Patient with true confirmed IgE mediated pen allergy… What other drugs should you be cautious of
Cephalosporins i.e. cefalexin
And carbapenems I.e. mero, erta
Convert oral morphine dose to subcut
Divide by 2
Drug causes of intracranial hypertension
Lithium, tetracyclines, vitamin A, oral contraceptive pill
What type of drug are exenatide and liraglutide
glucagon-like peptide-1 (GLP-1) mimetic, so increase insulin secretion and decrease glucagon,..
Weight loss!
Treatment for homocystinuria
vitamin B6 (pyridoxine)supplements
Half life of amiodarone
20-100 days!
Hence the loading dose
Pancreatitis caused by antiretroviral
didanosine
Mechanism of action: heparin
Activated antithrombin III
Rivaroxiban mechanism
Direct X inhibitor
how often should lithium levels be checked once a stable dose has been achieved?
Li-three-um
What antibiotics are contraindicated in preg
doxy, metronidazole,
management of complicated / severe falciparum malaria
IV artesunate
what drug can cause pellagra?
Isoniazid - as it inhibits conversion of tryptophan to niacin
do you treat B12 or folate deficiency first?
treat B12 def first to avoid precipitating subacute combined degeneration of the cord
drug that can cause dilated cardiomyopathy
Doxorubicin
which drugs can reactivate TB?
TNF-alpha inhibitors like etanercept
Patient started on statin, three months later, what blood result would make you stop them?
Treatment with statins should be discontinued if serum transaminase concentrations rise to and persist at 3 times the upper NORMAL limit of the reference range.
Terlipressin - method of action
constriction of the splanchnic vessels
Drug interactions with levothyroxine
iron, calcium carbonate, caffeine all reduce absorption
What increases absorption of iron?
Vitamin C (ascorbic acid) And gastric acid
Decreased by tea, PPI, tetracycline
Do macrolides inhibit the subunit 50S or 30S of ribosomes
buy AT 30, ‘CCEL’ at 50
(Aminoglycosides, Tetracyclines bind to 30S, Clinda, Chloramphenicol and Erythromycin bind to 50S
Common side effect of ticagrelor to remember
Dyspnoea in 15%
hypothesised that dyspnoea in is trigge ticagrelor inhibits adenosine clearance, thereby increasing its concentration
What receptor does Trastuzaumab (herceptin) act on?
HER2
T-two(2)–Trastuzaumab
What is side effect of cyclophosphamide and how do you prevent it
Haemorrhagic cystitis
Prevent it with hydration and Mesna
Management of patient on warfarin before dental surgery
check INR 72 hours before procedure, proceed if INR < 4.0
Patient with asthma has essential tremor. What is drug of choice?
Propranolol would be first line but given asthma, use primidone
What is a common side effect of Trastuzumab (Herceptin)
Cardiotoxicity, so usually get echo beforehand
Clopidogrel mechanism
Inhibits ADP binding to it’s platelet receptor
What is filgrastim used for and MOA
Filgrastim is a granulocyte-colony stimulating factor used to treat neutropenia
Contraindication of beta carotene
Can increase lung ca risk in smokers
MOA of amiodarone
Blocks potassium channels, which inhibits repolarisation so prolongs action potential,,
Diagnosis if taking anti malarials and then develop blood in urine, jaundice, bilirubinuria
Schistocytes and spherocytes on blood film
Haemolytic anaemia can be triggered by malaria prophylaxis in G6DP def
Nicorandil MOA
Potassium channel activator, through activation of guanylyl cyclase increasing cGMP
Patient in smoking cessation clinic. What are contraindications for bupropion?
norepinephrine and dopamine reuptake inhibitor, and nicotinic antagonist
Contra: seizures, preg, breast feeding
Oral morphine to SC syringe driver?
Oral morphine dose /3 = diamorphine dose
Which antibiotics inhibit 30S and 50S subunit of ribosomes, respectively?
Buy AT 30
CEL at 50
Aminoglycocydes (gentamicin, neomycin)
Tetracycline (doxy)
Clindamycin
Erythromycin
Linezolid
Non sedating antihistamines
Loratidine (LORRYtidine, because youd give it to lorry driver)
Citirizine (but less so)
First and second line for beta blocker OD
atropine
Glucagon if that fails
Can temporary pace
Benefits of metoclopramide in treating migraines
It is anti emetic but also prokinetic.. this treats the delayed gastric emptying often found in migraines, so names analgesia more effective
Which TCA has lowest toxicity in overdose?
Lofepramine
LOWfepramine
Side effect of the anti epileptic Vigabatrin
V for visual field defect
In up to 40%! May be irreversible
Patient of Thai decent has gout. What should you do
Screen for HLA-B*5801 before starting allopurinol due to high risk of severe cutaneous adverse reactions
MOA pilocarpine
Pilocarpine is a muscarinic agonist… Pupillary constriction
What drug may reduce effectiveness of adenosine
Adenosine Antagonised by Aminophylline
Drug causes of urticaria
Aspirin
Penicillin
Opioids
NSAIDs
When do you measure lithium levels
12 HR post
Please don’t check, Call just before, I have a Date at 6 so I’ll be Late at 12
Phenytoin .. No need to monitor
Cyclosporin .. Trough just b4 the dose
Digoxin .. 6 hrs after
Lithium .. 12 hrs after
When do you measure digoxin levels
6hr post
Please don’t check, Call just before, I have a Date at 6 so I’ll be Late at 12
Phenytoin .. No need to monitor
Cyclosporin .. Trough just b4 the dose
Digoxin .. 6 hrs after
Lithium .. 12 hrs after
When do you check different drug levels?
Trough levels immediately before dose
Please don’t check, Call just before, I have a Date at 6 so I’ll be Late at 12
Phenytoin .. No need to monitor (trough if suspected tox)
Cyclosporin .. Trough just b4 the dose
Digoxin .. 6 hrs after
Lithium .. 12 hrs after
What electrolyte abnormality precipitates digoxin toxicity
Hypokalemia… It allows dig to bind to Na/K ATPase more easily so increased inhibitory effect
MOA amiloride
Potassium soaring diuretic…
Blocks epithelial sodium channels in DCT
Spiro also acts on distal conv tub
Drugs that can be cleared with haemodialysis -
BLAST Barbiturates Lithium Alcohol (inc methanol and ethylene glycol Salicylates Theophylline
leukotriene receptor antagonist examples
Monteleukast
Clearance
= urine conc X urine volume / plasma conc
Treatment for cholera
PO doxy
Test before starting azithro
ECG (Qt)
LFTs
Hiccups in palliative care
chlorpromazine or haloperidol
SE ACEi
Cough Angioedema Hyperkalemic First dose hypotension - esp in AS, or diuretics
Avoid in preg/Bfeeding
Patient just started ticagrelor. SE
Dyspnoea can occur in first week. Can last hours or days.
MOA warfarin
Competitively inhibits vit k epoxide reductase
5 HT 1, 2 and 3
5 HT 1 agonist Triptan
5 HT 2 antagonist Pizotifen
5 HT 3 antagonist Ondansetron
Secondary prevention in stroke and Mi
Stroke: clopi long-term, statin if >3.5
MI: aspirin and 1yr ticagrelor, +ACEi, statin, BB
…continue ticagrelor if high risk
Sulphasalazine side effect
Oligospermia (doesn’t happen w, mesalazine)
Drugs that are zero order kinetics
Heparin
Ethanol
Aspirin
Phenytoin
….they’re saturated
MOA tocilizumab and sarilumab
monoclonal antibodies against IL-6 receptor
How long might it take for finasteride to improve BPH
Up to 6 months
Where does spironolactone act
Cortical collecting ducts
Tacrolimus SE
Tremor
