Pharmacology Flashcards

1
Q

Half life of mifepristone

A

25-30hours

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2
Q

Structure of heparin

A

Polysaccharide (repeating disaccarides)

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3
Q

Amount of hormone released in LNG in 24 hours (mirena)

A

20 micrograms/ 24 hours

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4
Q

MOA Fluconazole

A

Inhibits synthesis of ergosterol from lanosterol, inhibiting cell wall synthesis

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5
Q

MOA labetalol

A

Competitive alpha-1 (selective) and non-selective beta-1 blocker (antagonist)

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6
Q

MOA warfarin

A

Competitively inhibits vit K epoxide reductase complex 1. Interferes with synthesis of vitamin K dependent clotting factors (X, IX, VII and II- 1972)

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7
Q

MOA dalteparin

A

Factor Xa and thrombin inhibitor

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8
Q

MOA raltegavir

A

Integrase inhibitor

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9
Q

Metabolism of isoniazid

A

N-acetylation of its hydrazine in the liver

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10
Q

MOA of methotrexate

A

Dihydrofolate reductase inhibitor

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11
Q

MOA of clomiphene citrate

When should it be taken? Dose?

A

Selective estrogen receptor modulator:
Induces LH/FSH release by occupying oestrogen receptors in hypothalamus, promoting FSH release.
Stimulates ovarian aromatase activity and up regulate of granulosa LH receptors.

Stimulates ovulation

D2-6 of cycle. 50-100mg.

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12
Q

Dinoprostone MOA

A

Prostaglandin E2- stimulates uterine contractions

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13
Q

Contraceptive implant MOA

A

Ovulation inhibition and increase in viscosity of cervical mucus.

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14
Q

Teratogenic effect of ACEi

A

Fetal renal damage
Oligohydramnios
Skull defects

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15
Q

Most common side effect of oxybutynin

A

Dry mouth (antimuscarinic)

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16
Q

Absolute contraindications to COCP

A

<21 days post partum with other risk factors for VTE

0-6 weeks post partum and breastfeeding

Age >=35 and smokes >=15 cigarettes per day

Hypertension with BP >160 systolic or >100 diastolic

Vascular disease, heart disease, stroke/ TIA

History of VTE or current VTE

Major surgery (>30 mins) with prolonged immobilisation

Known thrombogenic mutation e.g. factor V Leiden

Antiphospholipid syndrome

Complicated valvular/ congenital heart disease (e.g. pulmonary hypertension)

Cardiomyopathy with impaired cardiac function

AF

Migraine with aura

Current breast cancer

Severe (decompensated) liver cirrhosis

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17
Q

MOA penicillins

A

Beta-lactam: inhibit peptidoglycan cross-links in bacterial cell wall synthesis (bactericidal)

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18
Q

MOA cephalosporins & examples

A

Beta lactam: inhibit peptidoglycan cross-links in bacterial cell wall synthesis (bactericidal)

Cefalexin, Ceftriaxone, Cefuroxime

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19
Q

MOA macrolides and examples

Excretion

A

Peptidyltransferase inhibitor. Reversibly bind 50S ribosome, block peptide elongation (bacteriostatic)

Erythromycin, Clarithromycin, Azithromycin

Excreted by liver

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20
Q

MOA fluoroquinolones and examples

A

DNA gyrase inhibitor- required to supercoil DNA = inhibit nucleic acid synthesis

Ciprofloxacin, Levofloxacin, Moxifloxacin, Ofloxacin

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21
Q

MOA Tetracyclines and examples

A

Bind to 30S subunit of microbial ribosomes, blocking attachment of aminoacyl-tRNA to the A site on the ribosome

Lymecycline, Oxytetracycline, Doxycycline

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22
Q

MOA Nitrofurantoin

A

Damages bacterial DNA via multiple reactive intermediaries

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23
Q

MOA Trimethoprim

A

Dihydrofolate reductase inhibitor (thus inhibiting bacterial DNA synthesis)

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24
Q

ACEi/ ARBs adverse effect on fetus/ neonate

A

Congenital Malformations
Renal dysgenesis
Oligohydramnios as a result of fetal oliguria
Pulmonary hypoplasia
IUGR
Neonatal anuric renal failure

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25
Q

Carbimazole adverse effect on fetus/ neonate

A

Choanal atresia
GIT defects
Omphalocoele
Aplasia cutis (missing section of skin)

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26
Q

Warfarin adverse effect on fetus/ neonate

A

Warfarin Embryopathy:
- Hypoplasia of nasal bridge
- Congenital heart defects
- Ventriculomegaly
- Agenesis of the corpus callosum
- Stippled epiphyses (focal bone calcification)
- Risk of intracranial haemorrhage in 3rd trimester
-Diaphragmatic hernia

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27
Q

Metronidazole adverse effect on fetus/ neonate

A

Diarrhoea
Lactose intolerance

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28
Q

Gentamicin/ Erythromycin adverse effect on fetus/ neonate

A

Ototoxicity

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29
Q

Tetracycline adverse effect on fetus/ neonate

A

Yellowing of teeth
Suggested link with cleft palate

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30
Q

Lithium adverse effect on fetus/ neonate

A

Cardiac Defects- Ebstein’s anomaly

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31
Q

Sodium Valporate adverse effect on fetus/ neonate

A

Cardiac Defects

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32
Q

SSRIs adverse effect on fetus/ neonate

A

Withdrawal syndrome in neonates
Some linked to CVS defects and Pulmonary Hypertension but evidence conflicting

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33
Q

Highest risk time to take warfarin?

A

6-12 weeks
5% chance of Warfarin emyropathy

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34
Q

Can Warfarin be used during breastfeeding?

A

Yes.

Women converted to LMWH during pregnancy should be changed back 5-7 days after delivery

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35
Q

Licensed use of Tamoxifen

Contraindications

MOA

A

Oestrogen receptor positive breast ca & anovulatory infertility

CI: personal or FHx of VTE

MOA: Selective Estrogen Receptor Modulator
(Increases risk of endometrial ca.)

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36
Q

Max dose of lidocaine

A

3mg/kg (without adrenaline)
7mg/kg (with adrenaline)

1% lidocaine = 1g/100ml or 10mg/ml.
Max dose for 70kg patient is 210mg = 21ml of 1% lidocaine

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37
Q

MOA of cyclizine

A

Histamine H1-receptor antagonist

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38
Q

MOA of Promethazine

A

Histamine H1-receptor antagonist

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39
Q

MOA Ondansetron

A

Serotonin 5-HT3 receptor antagonist

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40
Q

Prochlorperazine MOA

A

Dopamine D2 receptor antagonist

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41
Q

Metoclopramide MOA

A

Dopamine D2 receptor antagonist
5-HT3 receptor antagonist
5-HT4 receptor agonist

42
Q

MOA Lincosamide Abx and example

A

Interfere with synthesis of proteins via binding 50S ribosomal subunit, inhibiting peptide bond formation

Clindamycin

43
Q

MOA Terbinafine and amorolfine (anti-fungals)

A

Inhibit squalene epoxidase- enzyme that catalyses conversion of squalene to lanosterol.
Lanosterol is a precursor to Ergosgterol- a vital component of fungal cell walls.

44
Q

How does clomiphene trigger ovulation?

A

It inhibits oestrogen receptors in the hypothalamus, inhibiting the negative feedback effect of oestrogen.

This results in more GnRH release, therefore more LH/ FSH release from the anterior pituitary, driving ovarian follicular activity

45
Q

Risk of using metoclopramide in young people

A

Can cause oculogyric crisis (spasmodic movements of eyeballs into a fixed position, usually upwards) and is not licensed for people under 20 years old.

Should be limited to 5 days use.

46
Q

How many times stronger than morphine is fentanyl?

A

80 to 100 times stronger

47
Q

Codeine/ tramadol MOA

A

Agonists of the Mu receptor, but also agonists at the Delta and Kappa receptors

47
Q

Morphine’s primary MOA

A

Mu receptor agonist

As is fentanyl and methadone

48
Q

Benefits of antenatal steroids vs risks

Who is offered them

A

Benefits: Associated with significant reduction in rates of neonatal death, RDS and intraventicular haemorrhage & safe for mother

Risks: may cause low blood sugars in baby after birth. Less information on long term implications for babies, may affect brain development leading to delay in reaching developmental milestones, but evidence is limited.

Offered to women due to have planned CS between 37 and 39 weeks, probably reducing the chance the baby will need admission to neonatal unit for breathing problems

Also offered to those at risk of spontaneous vaginal birth 24+0 to 34+6 weeks gestation

49
Q

Regimens of antenatal corticosteroids

Who should receive them?

When are they most effective?

A

Dexamethasone IM 6mg x4 doses

Betamethasone 12mg IM x 2 doses 12h apart

Single course is recommended in women between 24+0 and 34+6 at risk of preterm delivery

Recommended for women having ELCS before 38+6

Most effective 24h- 7 days after administration

50
Q

MOA lidocaine

Lidocaine half life

A

Blocks fast voltage gated sodium channels

Half life 2h

51
Q

MOA metronidazole

A

Nitroimidazole class- inhibits nucleic acid synthesis by forming nitroso radicals, which disrupt the DNA of microbial cells

52
Q

Cabergoline and Bromocriptine are agonists of which receptor?

A

D2 –> reduce dopamine levels and milk production

53
Q

Half life of oxytocin

How long to respond following IV/ IM dose and when it subsides

A

5 minutes

Following intravenous administration, uterine response occurs almost immediately and subsides within 1 hour

Following intramuscular injection, uterine response occurs within 3 to 5 minutes and persists for 2 to 3 hours

Following iv infusion, steady state and maximal uterine activity is reached after 20-40 minutes hence oxytocin infusion is increased every 30 minutes

54
Q

Half life of Misoprostal

A

20-40 minutes

55
Q

Half life of ergometrine

A

30-120 minutes

56
Q

MOA of TXA

A

Plasminogen-activator inhibitor (Inhibits plasmin formation)

It inhibits the dissolution of thrombosis (and fibrin) that leads to menstrual flow.
It can reduce flow by up to 50%.

57
Q

MOA mefanamic acid

A

Works by inhibiting prostaglandin synthesis.

It reduces menstrual loss by around 25% in three quarters of women

58
Q

MOA heparin

A

Activation of Antithrombin III and inactivation of factor Xa

59
Q

MOA Mifepristone

A

Anti-progestogen: competes for progesterone receptors, acting as an antagonist

60
Q

Ulipristal (EllaOne) MOA

A

Selective anti-progesterone modulator

30mg single dose

Effective up to 5 days post SI

Inhibits ovulation

If vomiting within 3h repeat dose can be given

61
Q

Levenogestrel (Levonelle) MOA

A

Synthetic progesterone

1.5mg single dose ASAP after SI, licensed up to 72h post SI

If vomiting within 2h, repeat dose can be given

62
Q

Drug causes of hyperprolactinaemia

A

Atypical antipsychotics eg risperidone

Phenothiazines eg chlorpromazine

Butyrophenones eg haloperidol

Thioxanthenes

Metoclopramide

Dopamine synthesis inhibitors eg -Methyldopa

Catecholamine depletors eg Reserpine

Opiates eg Codeine

H2 antagonists eg Cimetidine, Ranitidine

Amitriptyline

SSRI’s eg Fluoxetine

Calcium channel blockers eg Verapamil

Oestrogens

Thyrotropin-releasing hormone (TRH)

63
Q

MOA Atosiban

A

Oxytocin receptor antagonist

64
Q

MOA traditional POP vs desogestrel only & brand names

A

Traditional POP: thickening of cervical mucus
- Norgeston
- Micronor & Noriday
- Femulen

Desogestrel POP: inhibits ovulation
- Cerezette
- Aizea
- Cerelle
- Nacrez

65
Q

Which local anaesthetic is an amide and which are esters?

A

Lidocaine = amide

Benzocaine/ Cocaine/ Procaine/ Tetracaine = esters

66
Q

Which neurotransmitter is used by the sympathetic/PS preganglionic neuron?

A

ACh

67
Q

MOA Methyldopa

A

Centrally acts as alpha 2 receptor agonist

68
Q

MOA Cyclizine

A

H1 antagonist

69
Q

Why is Vit D recommended in pregnancy?

A

Prevent rickets in neonate

70
Q

Which COCP is beneficial in PCOS?

A

Yasmin (ethinylestradiol/ drosperinone)- beneficial for acne and hirsutism

Dianette (cyproterone acetate, ethinylestradiol)- not if high BMI- high risk of VTE

Both are anti-androgenic

71
Q

Medication for stress UI

A

Duloxetine

5HT and NA reuptake inhibitor- increases urinary sphincter tone

72
Q

Medication for urge UI/OAB, MOA & contraindications

A

Tolterodine (M1-4) (1st line)

Oxybutynin (M1-4) (1st line)

Darifenacin (1st line)

Solifenacin (Vesicare) (M2/3 receptors) (2nd line)

MOA: Both muscarinic receptor antagonists- inhibit detrusor contractions

CI: Closed angle glaucoma (pilocarpine eye drops are muscarinic receptor agonists), Myasthenia graves, paralytic ileus

Mirabegron can be used if anti-muscarinic is CI (selective beta3 adrenorecptor agonist)

73
Q

MOA anti-thyroids

A

Propylthiourcil and carbimazole

Prevent the peroxidase oxidation of iodide to iodine in the thyroid gland

Propylthiouracil also has a peripheral action (prevents deionisation of thyroxine)

74
Q

LMWH MOA

A

Inhibits factor Xa by binding to anti-thrombin, thereby inhibiting the conversion of prothrombin to thrombin

75
Q

Progestogens in contraception and their risk of VTE

A

COCs containing levonorgestrel, norethisterone and norgestimate carry the lowest risk of VTE.

Etonogestrel and norelgestromin are slightly higher

Highest risk: estrogen and drospirenone, gestodene, desogestrel, and co-cyprindiol (cyproterone/ethinylestradiol).

76
Q

Why can’t clomifene be used >6 months

A

Increased risk of ovarian cancer

77
Q

MOA glycopeptides and examples

G neg or positive bacteria?

A

Inhibit bacterial cell wall synthesis by binding to d-alanyl-d-alanine, preventing incorporation of new subunits

Vancomycin & teicoplanin
(associated with red man syndrome)

Only active agains gram positive bacteria

Not absorbed in GIT

78
Q

Aminoglycosides MOA and examples

G neg or positive bacteria?

Excretion

A

MOA: inhibit bacterial protein synthesis. Irreversibly bind to 30S ribosomal proteins (bactericidal)

Gentamicin, Tobramycin, Netilmicin, Streptomycin

Active against G negative bacteria

Excreted via kidneys

79
Q

Sulfonamides MOA and examples

Metabolism

A

MOA: inhibit bacterial synthesis of tetrahydrofolic acid= antimetabolite

Sulfasalazine, Sulfamethazine, sulfamethoxazole (in co-trimoxazole with trimethoprim)

Active orally, metabolised by liver, excreted by kidneys

Recognised cause of SJS

80
Q

Anti-retroviral medications
Classes, examples and MOA

A
  1. Nucleotide reverse transcriptase inhibitors (NRTIs)
    e.g. Zidovudine, Tenofovir, Lamivudine

MOA: Target HIV reverse transcriptase, disrupting creation of proviral DNA, halting HIV replication.

  1. Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
    e.g. Doravirine, Efavirenz, Etravirine, Nevirapine, Rilpivirine

MOA: bind directly to reverse transcriptase, blocking its action

  1. Integrase inhibitors
    e.g. Raltegravir, Elvitegravir

MOA: target HIV integrase, which is needed for viral replication. Integrase inserts viral genomic DNA into host chromosome.

  1. Entry inhibitors
    e.g. Maraviroc, enfuviritide

MOA: stop HIV from entering human cells. HIV must bind CD4 receptor and a co-receptor (CCR5 or CXCR4), entry inhibitors block one of these co-receptors.

  1. Protease inhibitors
    e.g. Atazanavir, Darunavir, Lopinavir

MOA: block activity of protease enzyme, which HIV uses to break up large poly proteins into smaller pieces to make new viral particles from.

  1. Post attachment inhibitors e.g. Ibalizumab

MOA: bind CD4 receptor, preventing HIV GP120 protein from changing shape to engage with co-receptors.

  1. Booster drugs
    e.g. Ritonavir, Cobicistat

MOA: boost effects of protease inhibitors- make the liver breakdown the PI more slowly, reducing clearance and increasing plasma levels.

81
Q

Chloramphenicol effect on fetus

A

Neonatal gray syndrome

82
Q

Carbamazepine effect on fetus

A

Diminished growth and hypospadias

83
Q

Sodium valproate effect on fétus

A

Neural tube defects

84
Q

Vitamin A/ retinoids effect on fetus

How long should be discontinued before conception

A

Skeletal deformity

Accumulates in skin/ fat therefore avoid conception for 2 years after treatment

85
Q

Diuretic effect on fetus

A

Neonatal thrombocytopenia

86
Q

Atenolol effect on fetus

A

IUGR
Neonatal hypohlycaemia
Bradycardia

87
Q

Prostin
Gemeprost
Carboprost
Misoprostol

What type of PG?

A

Prostin = PGE2

Gemeprost = PGE1 analogue (PV)

Carboprost = 15methyl PGF2alpha (IM)

Misoprostol = PGE1

88
Q

How many amino acids in Oxytocin?
Where is it synthesised?
What receptors does it work on?
How can it cause hyponatraemia?

A

9

Paraventricular nuclei

Acts through G protein couples receptor and allium-calmodulin complex

Has ADH like effects and can cause hyponatraemia, reflex hypotension and tachycardia

89
Q

Tocolytics & MOA

When should they be used?

A

Nifedipine or Atosiban to allow time for steroids to work +/- in utero transfer if needed 24w-33w gestation

Atosiban = oxytocin receptor antagonist (IV infusion)

Nifedipine (CCB)- PO & cheaper than above
20mg PO, then 10-20mg TDS/ DQS according to uterine activity for 48h

Terbutaline 250mcg SC (emergency) = beta 2 adrenergic receptor agonist

90
Q

Dose of MgSO4 for PET

A

4g loading dose
1g/h maintenance dose

91
Q

Prevention/ management of PPH
Drugs & doses

A

Active management of third stage:
- IM oxytocin (5u, 10u) OR 1ml syntometrine (500mcg ergo and 5u oxytocin- IM)
- IV oxytocin (5u at CS or f/u dose)
- Ergometrine 250-500mcg IM or slow IV
- IV infusion 40units oxytocin in 40ml saline at 10ml/h
- Carboprost 250mcg IM, repeated every 15min as needed. Total dose shouldn’t exceed 2mg (8 doses)
- Misoprostol 1000mcg PR

92
Q

Pethidine
- Dose
- Side effects
- When is it at its highest concentration in the foetus
- How does it cross the placenta

A
  • Dose: 50-100mg every 4h IM
  • Delays gastric emptying, resp depression and hypoventilation
  • Highest fetal concentration 2-3h post IM injection. Fetal concentrations are higher than maternal because its a weak base and more ionised in the acidic environment of the fetal circulation
  • Binds to alpha1 acid glycoprotein and readily crosses placenta by passive diffusion
93
Q

Drugs that suppress lactation

A

Bromocriptine (D2 agonist)
Cabergoline (D2 agonist)
Aspirin
Tetracyclines
Ciprofloxacin
Litium
DIazepam
Carbimazole
Caffeine
Nicotine

94
Q

Safe in breastfeeding

A

NSAIDs, codeine (check baby not drowsy), morphine, methadone

Penicilins, cephalosporins, macrolides

Labetalol, nifedipine, captopril, enalapril, metoprolol, atenolol, amlodipine

Phenytoin, carbemazepine, sodium valproate

SSRIs, TCAs

Warfarin
Heparin
Insulin

95
Q

Drugs that increase prolactin

A

Metoclopramide, Domperidone

Amisulpride & most other antipsychotics

Verapamil, Methyldopa

Estrogen and COC

96
Q

When is a Cu-IUCD appropriate for emergency contraception?

A

May be inserted within 5 days UPSI or not more than 5 days after known ovulation

Use instead of levonelle or Ellaone if patient also on Liver enzyme inducing medication, as this may affect their efficacy

97
Q

Examples of alkylating agents and how they work

A

Cylophosphamide
Chlorambucil

Form covalent bonds with DNA side chains, causing deprivation, strong breaks and cross linking

97
Q

How does diazepam cross placenta?

A

Can cross readily due to lipid solubility

98
Q

Anti-metabolite that is the pro-drug for 6-mercaptourine & MOA

A

Azathioprine

MOA: Antagonizes purine metabolism and inhibits synthesis of DNA, RNA, and proteins.

99
Q

Drug associated with haemorrhage cystitis

A

Cyclophosphamide

100
Q

Which SSRI should be avoided in first trimester and why?

A

Paroxetine- causes fetal heart defects