B10 Flashcards

1
Q

Enalapril,
Lisinopril,
Ramipril,
Captopril

A

ACE inhibitors

Competitive inhibitor of angiotensin-converting enzyme.

MoA: They prevent conversion of angiotensin I to angiotensin II (ATII). ATII regulates blood pressure and is a key component of the renin-angiotensin-aldosterone system (RAAS).

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2
Q

How does angiotensin II increase blood pressure?

A

ATII increases blood pressure using several mechanisms:
♣ Stimulation of secretion of aldosterone from the adrenal cortex
♣ Stimulation of Vasopressin secretion from the posterior pituitary gland
♣ Through direct arterial vasoconstriction
♣ ATII induces the thirst response via stimulation of hypothalamic neurons

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3
Q

ACEis involved in deactivation of bradykinin

Inhibiting deactivation of bradykinin increases bradykinin levels causing what?

A

Increased vasodilation and decreased blood pressure

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4
Q

Amiloride

A

Sodium channel blocker (ENaC antagonist)

It is an antihypertensive, potassium-sparing diuretic often used in conjunction with thiazide or loop diuretics.

MoA: Antikaliuretic-diuretic:
o Directly inhibit epithelial Na+ channel (ENaC) in late DCT + CD
o Reduces Na+ reabsorption hyperpolarisation of apical membrane
o Makes luminal potential more positive + inhibits K+ secretion

Use: Due to its potassium-sparing capacities, hyperkalaemia (high blood potassium levels) are occasionally observed.

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5
Q

There are 5 targets of the nephron. List them.

A
  1. Carbonic anhydrase inhibitorr - Proximal tubule
  2. Osmotic diuretics (e.g. Mannitol) - thin descending limb of the loop of henle
  3. Na-K-Cl co-transporter inhibitor - thick ascending loop of henle
  4. Na-Cl transport inhibitor - Distal convoluted tubule
    - Thiazides, Chlorothiazides, Hydrochlorothiazides
  5. Mineralocorticoid receptor antagonist, ENaC antagonist, ADH antagonist (K-sparing) - Collecting duct
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6
Q

Bendroflumethiazide

A

Thiazide diuretic

Acts on distal tubule like all thiazide diuretics.

MoA:
• Inhibiting carbonic anhydrases in the smooth muscle
• Activating the large-conductance calcium-activated potassium (KCa) channel, in the smooth muscle

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7
Q

Chlorthalidone

A

A monosulfonamyl diuretic

It form other thiazide diuretics in that a double ring system is incorporated into its structure

MoA: Chlorthalidone inhibits Na+ transport across the renal tubular epithelium in the ascending limb of LoH. By increasing the delivery of sodium to the distal renal tubule and collecting duct, Chlorthalidone indirectly increases potassium excretion via the sodium-potassium exchange mechanism

Use: Chlorthalidone is used alone or with atenolol in the management of hypertension and edema

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8
Q

Spironolactone

A

Mineralocorticoid nuclear hormone receptor antagonist

A potassium sparing (weak) diuretic

MoA: Spironolactone inhibits the effect of aldosterone by competitively competing for intracellular aldosterone receptor in the distal convoluted tubule cells.

Spironolactone bind to this mineralocorticoid receptor, blocking the actions of aldosterone on gene expression.

Note: Spironolactone has a slow onset of action, taking several days to develop and similarly the effect diminishes slowly.

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9
Q

Acetazolamide

A

A reversible carbonic anhydrase inhibitor (proximal tubule) –> Increases Na/H/CO3 excretion

MoA: Acetazolamide inhibits carbonic anhydrase leading to a reduction in the availability of hydrogen ions for active transport in the renal tubule lumen.

This leads to alkaline urine and an increase in the excretion of bicarbonate, sodium, potassium, and water

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10
Q

Doxazosin

A

A selective alpha-adrenergic inhibitor

MoA: Doxazosin is a selective inhibitor of the alpha1 subtype of alpha adrenergic receptors.

Doxazosin inhibits the postsynaptic alpha (1)-adrenoceptors on vascular smooth muscle. Blocking the vasoconstrictor effect of circulating and locally released catecholamines. In the human prostate, Doxazosin competitively antagonized the pressor effects of phenylephrine (an alpha1 agonist) and the systolic pressor effect of norepinephrine

Use: Therefore is used to treat hypertension and benign prostatic hyperplasia.

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11
Q

Cisplatin

A

An alkylating agent used to treat cancer

MoA: Alkylating agents are cell cycle-nonspecific (cancer drugs) that can work via 3 mechanisms. These mechanisms affect the ability of DNA to uncoil and separate, preventing DNA replication and therefore cell proliferation, leading to cell death.

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12
Q

Methotrexate

A

An antineoplastic anti-metabolite

  • Antimetabolites are synthetic versions of purine or pyrimidines

MoA: Methotrexate inhibits folic acid reductase which converts folic acid to tetrahydrofolic acid.
Tetrahydrofolic acid is required for both purines and pyrimidine biosynthesis, Thus, DNA synthesis cannot proceed due to a lack of purine and pyrimidines. Given this effect on DNA, Methotrexate affects the most rapidly dividing cells.

Use: The management of severe, active, classical, or definite rheumatoid arthritis

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13
Q

Phenobarbital

A

A barbiturate which acts on GABA receptors, increasing synaptic inhibition

MoA: Phenobarbital acts on GABA receptors, increasing synaptic inhibition.

This has the effect of elevating seizure threshold and reducing the spread of seizure activity from a seizure focus.

The sedative-hypnotic effects of phenobarbital are likely the result of its effect on the polysynaptic midbrain reticular formation, which controls CNS arousal.

Use: Phenobarbital, the longest-acting barbiturate, is used for its anticonvulsant and sedative-hypnotic properties in the management of all seizure disorders except absence (petit mal)

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14
Q

Meperidine

A

Use: Meperidine is a synthetic opiate agonist recommended for relief of moderate to severe acute pain.

Note: The onset of action is more rapid than morphine, but has a shorter duration of action.

MoA: Meperidine is a kappa-opiate receptor agonist with local anaesthetic effects.

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15
Q

Mannitol

A

An osmotic diuretic

Mannitol is a metabolically inert osmotic diuretic which is present naturally in the diet. Mannitol elevates blood plasma osmolality, resulting in enhanced flow of water from tissues, including the brain and cerebrospinal fluid, into interstitial fluid and plasma.

MoA: Mannitol induces diuresis as it is not reabsorbed in the renal tubule, and therefore increases the osmolality of the glomerular filtrate. This aids water excretion.

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16
Q

Pethidine

A

A synthetic opiate agonist

It’s aka meperidine

17
Q

Amphetamine

A

A non-catecholamine sympathomimetic

Catecholamine (NA, 5HT, DA) releaser

MoA: Amphetamines acts in multiple manners dependent on the dose. They can act:
o By stimulating the release of norepinephrine from central adrenergic receptors.
o By stimulating the release of dopamine from the mesocorticolimbic and nigrostriatal systems.
o As a direct agonist on central 5-HT receptors
o By possibly inhibiting monoamine oxidase (MAO).
o In the periphery, amphetamines can cause the release of noradrenaline by acting on the adrenergic nerve terminals and alpha- and beta-receptors.

18
Q

Furosemide

A

A loop diuretic.

Acts on the thick ascending limb of the LoH

MoA: Acts on ascending limb of the LoH to increases water, K+, Cl- excretion.
♣ Furosemide, inhibits the Na-K-Cl cotransporter, via competitive inhibition of the Cl- binding site, in the thick ascending limb of the loop of Henle.
♣ This inhibition prevents sodium transport from the lumen of the loop of Henle into the basolateral interstitium.
♣ Therefore, as the lumen becomes more hypertonic, this alters the osmotic gradient, causing the retention of water within the lumen.