Medications Flashcards
What is tocilizumab?
What are its current main uses in adults?
Interleukin-6 receptor antagonist. Leads to a reduction in cytokine and acute phase reactant production
Uses:
- Giant cell arteritis
- Rheumatoid arthritis as second line, if TNF fails or can’t be used
Main risk -> bowel perforation in previous diverticulitis
What is abatacept?
What are its current main uses in adults?
CTLA-4 fusion protein. Selective costimulation modulator, inhibits T-cell activation by binding to CD80 and CD86 on antigen presenting cells
Uses:
- Psoriatic arthritis
- Rheumatoid arthritis, may be used as monotherapy or in combination with other DMARDs
SEs: Infusion site reaction, headache, dizziness
What is Tofacitinib?
What are its current main uses in adults?
JAK inhibitor, preventing cytokine or growth factor-mediated gene expression and intracellular activity of immune cells
Uses:
- Psoriatic arthritis as second line after methotrexate or other DMARDs
- Rheumatoid arthritis, as monotherapy or in combination with methotrexate or other nonbiologic DMARDs) in adults who have had an inadequate response to, or are intolerant of, methotrexate
- Ulcerative colitis as second line after TNF inhibitors
SEs: High risk of shingles
What is Belimumab?
What are its current uses?
Monoclonal antibody that inhibits the soluble form of a B-cell survival factor (known as BLyS or BAFF). Inhibits survival of memory B cells and plasmablasts making autoantibodies
Uses:
- SLE that is treatment refractory
No data in CNS or renal disease
What is Trastuzumab?
What are its uses?
Monoclonal antibody against HER2 receptor
Used in HER2 positive breast cancer as adjuvant chemotherapy
What is the main mechanism of action of antipsychotics?
Dopamine D2 blockers or partial blockers
What is the most efficacious antipsychotic?
Clozapine
Which antipsychotic has highest risk of EPSE?
Which has the lowest?
Haloperidol
Clozapine
Which antipsychotic leads to most prolactin elevation?
Paliperidone
Which antipsychotic has highest metabolic / weight gain risk?
Olanzepine
Which antipsychotic is highest risk for QT prolongation?
Amisulpride
What substance has a higher risk of addiction than heroin?
Tobacco
What is the common pathway activated by many drugs of abuse?
Mesolimbic dopamine system
Which two neurochemical systems are involved in ETOH intoxication?
GABA
NMDA
What is the long-term treatment of choice for opioid replacement?
Suboxone -> buprenorphine + naloxone
Question A woman with metastatic breast cancer and painful bone secondaries develops nausea and vomiting. She is found to have a bowel obstruction and is admitted and made nil orally. She usually takes MS Contin 70 mg bd, and 2 mls of morphine mixture 10 mg/ml for breakthrough pain, usually twice each day. The bowel obstruction has not exacerbated her pain. The best estimate of the equivalent parenteral four hourly dose of morphine is: A. 2 mg. B. 10 mg. C. 5 mg. D. 50 mg. E. 20 mg.
B - 10mg (q4hourly)
Calcium Carbonate absorption would be most affected by the co-administration of: A. Alendronate B. Cholestyramine C. Hydrochlorothiazide D. Omeprazole E. Rifampicin
D. Omeprazole
- Correct, as above, reduces gastric acidity which reduces absorption of calcium carbonate
Which of the following will help most to improve systolic function in heart failure: A. ACE Inhibitors B. Beta Blockers C. Digoxin D. Hydralazine E. Spironolactone
B - beta blockers
Question 5. Medication withdrawal is frequently undertaken in elderly patients with polypharmacy. Which of the following medications can be stopped abruptly with minimal risk of a withdrawal syndrome in older people? A. Levodopa. B. Metoprolol. C. Oxazepam. D. Sertraline. E. Amlodipine.
E - amlodipine
Question 2010 A31
What is the main mechanism of action of the dihydropyridine calcium channel antagonists?
A. inhibition of the RAAS
B. Decreased sympathetic activity
C. Reduction in vascular smooth muscle tone
D. Decreased sodium excretion
E. Negative ionotropic effect
C. Reduction in vascular smooth muscle tone
Which of the following ratios best estimates the equivalent oral to parenteral morphine? A. 1:1 B. 2:1 C. 3:1 D. 4:1 E. 5:1
C - 3:1
Question 61. Which of the following drugs newly prescribed to a patient with stable and therapeutic lithium levels is most likely to produce an increase in his serum lithium? A. Fluoxetine B. Theophylline C. Captopril D. Hydrochlorothiazide E. Aspirin
D - thiazide
HCT → MAKES YOU HYPONATRAEMIC → BODY RELEASES ALDOSTERONE AND ADH → REABSORPTION OF NA THROUGH ENAC CHANNELS → INCREASING LITHIUM REABSORPTION THROUGH ENAC CHANNELS
What effect do changes in urinary pH have on drug metabolism?
i.e. If urine is more alkali, what effect will this have on acidic drugs and basic drugs?
If urine is more acidic, what effect will this have on acidic drugs and basic drugs?
Alkaline urine: acidic drugs are more readily ionised
Acidic urine: alkaline drugs are more readily ionised
Ionised substances = polar = more soluble in water and so dissolve in the body fluids more readily for
excretion.
In alkali urine, acidic drugs have increased excretion
In acidic urine, basic drugs have increased excretion
QUESTION 3 28 year old woman admitted to high dependency unit 4 hours after an overdose of amitriptyline for cardiac monitoring. She is drowsy and nauseated. Her ECG shows a QRS length of 140msec. Which one of the following would help minimise risk of amitriptyline related cardiac toxicity? A. Activated Charcoal B. Haemodialysis C. Magnesium D. Metoprolol E. Sodium Bicarbonate
E - Sodium bicarb
Treatment/Antidote Sodium bicarbonate -> Serum alkalinisation for prolonged QRS o QRS >100ms is the indication o Reverses the toxic effects of TCAs -> 100mmol (2mmol/kg) every few mins
Q46 Serotonin syndrome is a potentially life threatening complication of SSRIs. Which class of drug when used with SSRIs is most likely to precipitate this syndrome? A. Benzodiazepine B. Dopamine agonist C. Dopamine carboxylase inhibitor D. Monoamine oxidase inhibitor E. Phenothiazine
D. Monoamine oxidase inhibitor - yes
QUESTION 2012 B59
A patient is undergoing cisplatin therapy for the management of metastatic testicular cancer. He is
given dexamethasone, metoclopramide and ondansetron prior to receiving his chemotherapy. He
suddenly complains of dizziness and nausea, feeling stiff and that his vision is funny. What is the
immediate management of this man’s problem?
A. Aspirin
B. IV hydrocortisone
C. IV benztropine
D. Cease cisplatin infusion
E. Do nothing & reassure
C - IV benztropine
Acute dystonic reaction / oculogyric crisis
QUESTION 2013 A1 What is the most appropriate treatment for severe lithium toxicity? A) Frusemide and normal saline B) Normal saline alone C) Haemodialysis D) Plasma exchange E) IV bicarbonate
C - HDx
Lithium is readily dialysable due to low molecular weight, negligible protein binding and small volume of distrubution
Q 53 Many drugs in drug overdose exhibit zero order kinetics. Which of the following is most correct regarding zero order kinetics? A- clearance is constant B- elimination is constant C- protein binding is saturated D- tissue distribution is saturated E- drug efflux proteins are saturated
B - elimination is constant
Question What factor of drug pharmacokinetics is most affected in obese individuals? A. Volume of distribution B. Maximum concentration C. Half life D. Protein binding E. Clearance
A - Vd
What is the equation for Vd (volume of distribution)?
Vd = amount of drug in the body / plasma drug concentration
What is the equation for clearance of drug?
Clearance = rate of drug elimination / plasma drug concentration
What is the formula for a drug’s half-life?
t1/2 = (0.693 x Vd) / Clearance
How do you calculate bioavailability?
Bioavailability is calculated from AUC(route)/AUC(IV)
How do you calculate the ideal dosing rate for a drug?
Dosing rate = (Clearance x Desired Plasma Concentration) / Bioavailability
If this is calculated per minute -> x 60 min/hour, x 24 hours/day for daily dose
Doses per day can then be determined by half-life
How is loading dose calculated?
Loading dose = (Vd x Desired Plasma Concentration) / Bioavailability
Botulinum toxin is a large protein molecule. Its action on cholinergic transmission depends on an intracellular action within nerve endings. Which one of the following processes is best suited for permeation of very large protein molecules into cells?
A - Aqueous diffusion B - Endocytosis C - First-pass effect D - Lipid diffusion E - Special carrier transport
B - endocytosis. Endocytosis is an important mechanism for transport of very large molecules across membranes. Aqueous diffusion is not involved in transport across the lipid barrier of cell membranes. Lipid diffusion and special carrier transport are common for smaller molecules. The first-pass effect has nothing to do with the mechanisms of permeation; rather, it denotes drug metabolism or excretion before absorption into the systemic circulation.
When in pregnancy should NSAIDs be avoided?
3rd trimester
- contraindicated in the 3rd trimester due to the risk
of premature closure of the ductus arteriosus due to the inhibition of prostaglandin synthesis
