pharmacology Flashcards

(44 cards)

1
Q

Describe Volume distribution

A

apparent volume into which the drug would have to distribute to achieve the measured concentration. The higher the VD the higher the loading dose of medication needed.

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2
Q

What is the formula for volume distribution

A

Amount of medication in mg/ plasma concentration of given medication

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3
Q

Define clearance

A

the ability of the body to remove a drug from the plasma or blood and is the sum of drug clearances of each organ (usually kidney + liver)

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4
Q

What formula is appropriate for calculating dosage of drugs given intravenously ?

A

(target concentration (mg/L)) x (clearance (L/hr/kg))

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5
Q

How does volume distribution relate to Neonates?

A

Neonates have higher body water, therefore they have a lower Vd for fat-soluble drugs and higher Vd for water-soluble drugs (see below).

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6
Q

Grapefruit juice contains potent inhibitors of what?

A

Cytochrome P450

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7
Q

Grapefruit juice increases the bioavailability of what medications?

A

MidazolamCarbamazepine Cyclosporin

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8
Q

What antibiotic groups require therapeutic drug monitoring and why?

A

Aminoglycosides -For gram negativeGlycopeptides- for gram positiveBoth can cause oto/mephro toxicity

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9
Q

What is MOA of aminoglycosides?

A

bactericidal and works by irre­versibly binding the 30S subunit of the bacterial ribos­ome, and interfering with bacterial protein synthesis.

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10
Q

What is MOA of Glycopeptides?

A

Affect cell-wall synthesisi in gram positive bacteria. They bind to the end of the pentapeptide chains that are part of the growing cell wall structure. This inhibits the transglycosylation reaction and prevents incorporation.

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11
Q

Describe Red Man syndrome

A

Caused by Vanc. Flushing and erythematous skin usually of the upper body and face. Caused by a non-specific mast cell degranulation. Avoided with a slow infusion rate.

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12
Q

What are the phase 1 drug metabolism pathways?

A

OXIDATIONhydrolysis reduction hydration

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13
Q

What are the phase 2 drug metabolism pathways?

A

GlucuronidationMethylationSulfation Acetylation

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14
Q

What medications are metabolised by CYP3A4?

A

CarbamazepineDiazepamErythromycinFentanylMidazolamNifedipineOndansetronRifampicin

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15
Q

What medications are metabolised by CYP2D6

A

AmitriptylineCodeineSelective serotonin reuptake inhibitors

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16
Q

What medications are metabolised by glucuronidation?

A

ParacetamolMorphine

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17
Q

What medications are metabolised by CYP1A2?

A

CaffeineTheophylline

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18
Q

What medications are metabolised by CYP2C9?

A

Phenytoin Ibuprofen

19
Q

What medications are metabolised by sulfation?

20
Q

What common group of enzymes control oxidation.

A

CYP450 phase 1 baby

21
Q

How does Cystic fibrosis affect drug clearance?

A

Increases it. Will need higher doses of medicationThink Tobromycin

22
Q

In what population of ceftriaxone prohibited?

A

premature infantsfull-term infants with jaundiceany child recieving calcium

23
Q

Viral illness + what type of medication causes Reye’s syndrome?

A

Salicylates (Aspirin)

24
Q

What is MOA of paracetamol?

A

Inhibition of COX enzymes prevents the metabolism of arachidonic acid to prostaglandins. In the central nervous system, inhibition of COX enzymes reduces concentrations of prostaglandin E2, which lowers the hypothalamic set-point to reduce fever, and activation of descending inhibitory serotonergic pathways to produce analgesia.

25
Where is paracetamol not effectively absorbed?
Gastric mucosa Therefore give rectally/ IV to kids with poor gastric emptying.
26
How is paracetamol metabolised?
Glucuronide conjugation (accounting for 40–60% of a dose in adults), sulfate conjugation (20–40%), and N-hydroxylation via the cytochrome P450 isozyme CYP2E1 (<15%). This latter mecha­nism produces a highly toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI), which requires conjugation with glutathione to form a non-toxic metabolite that can be excreted.
27
What is mechanism of paracetamol overdose?
glucuronidation and sulfation pathways become saturated. More CYP2E1 metabolism, glutathione stores become depleted, resulting in excess quantities of NAPQI resulting in hepatotox­icity.
28
What is the treatment for paracetamol overdose?
The treatment of paracetamol poisoning, N-acetylcysteine, increases the glutathione stores so that the buildup of NAPQI can be conjugated and excreted.
29
how do NSAIDs treat inflammation?
Inhibit cyclo-oxygenase, the enzyme that transforms arachidonic acid to prostaglandins and thromboxanes
30
How do NSAIDs treat fever?
Inhibition of prostaglandin E2 (PGE2) synthesis, which normally triggers the hypothalamus to increase body temperature during inflammation.
31
How is morphine metabolised?
Morphine is extensively metabolized by the gut wall and the liver. Glucuronidation by the liver enzyme UGT2B7 converts morphine to morphine-3-glucuronide (M3G) (70%) and morphine-6-glucuronide (M6G) (10%).
32
What are the 3 types of antibiotics?
Cell wall inhibitors Protein synthesis inhibitors Nuclei synthesis inhibitors
33
What are the classes and MOA of cell wall inhibitors?
β-Lactams are bactericidal and act by binding to enzymes known as penicillin binding proteins (PBPs) and inhibiting cell wall synthesis.Glycopeptides -bind to the end of the pentapeptide chains that are part of the growing cell wall structure. This inhibits the transglycosylation reaction and prevents incorporation.
34
What are the classes and MOA of protein synthesis inhibitors?
Aminoglycosides - bactericidal and works by irre­versibly binding the 30S subunit of the bacterial ribos­ome.Chloramphenicol - blocks the action of peptidyl transferase thereby preventing peptide bond synthesis and subsequently inhibiting bacterial protein synthesisMacrolides - primarily bacteriostatic and act by binding to the 50S subunit of the ribosomes.
35
What are the classes and MOA of Nucleic syntheis inhibitors?
Sulphonamides - bacteriostatic and act as competitive inhibitors of the enzyme dihydropteroate synthetase (DHPS) which is involved in bacterial folate synthesis.Quinolone - inhibiting the activity of DNA gyrase and therefore preventing supercoiling of the bacterial chromosome. This prevents the bacterial cell from putting DNA into its cell
36
Give an example of Quinolone and what is it used for?
Ciprofloxacin Pseudomonal infections in children with CF or complicated UTIs
37
Give an example of Macrolides and what is it used for?
clari/azithro/erythro -mycinatypical respiratory tract infections
38
Give an example of sulphonamides and what is it used for?
Trimethoprim Gram negative e.coli in UTIs
39
Give an example of Glycopeptides and what is it used for?
Vancomycin and teicoplaninGram positive staphylococci. MRSA/ c.diff
40
Give an example of Aminoglycosides and what is it used for?
Gentamycin + tobramycinSevere gram negative infectionsgent synergises with β-lactams to treat group B strep hence benpen + gent.
41
What are the types of β-lactam antibiotics?
PenicillinsCo-amoxiclav2nd + 3rd generation cepholasporins
42
Give an example of 2nd generation cephalosporins and what is it used for?
CefuroximeHaemophilus influenzae or where there is resitance/ severity.
43
Give an example of 3rd generation cephalosporins and what is it used for?
CefoTAXime, CefTRIaxoneGram-negative infections, such as Neisseria meningitides.
44
What class of antibitic is ceftazidime and what does it have good action against?
third-generation cephalosporinGood against pseudomonas