8 - Pharmacology of AntiHT's Flashcards
What drug based on MOA?
Selectively block a1-adrenoreceptors
@arterioles & venules
↓Arterial pressure
by dilation of resistance/capacitance BVs
Vasodilation –> HypoTensive effect
- *a1-adrenoceptor Antagonists**
- *Prazosin / Terazosin / Doxazosin**
orthostatic hypotension
What drug based on MOA?
**Inhibit NaCl Reabsorption in the DCT** in luminal (urine-side) epithelium
Direct effect:
Block Na+/Cl- Transporter
Enhances Ca2+ Reabsorption
THIAZIDES
Chlorthiazide / HCTZ / Methylclothiazide
Non-thiazide Sulfonamide:
Chlorthalidone / Indapamide / Metolazone
Fenoldopam
Class / MoA / ADR
Parenteral Vasodilator
- *Dilates Arterioles**
- not veins*
D1 Agonist –> also produces natriuresis
↑Intraocular pressure = do NOT use in GLAUCOMA pts
ADRs:
TachyCardia & Provokes ANGINA
What drug based on MoA?
- *Dilates Arterioles**
- no vein effect*
TachyPhalaxis
develops rapidly, limits use in MONOtherapy
Usually used for:
Combination Therapy for Severe HTN
HYDRALAZINE
Oral Vasodilator
may provoke ANGINA
Which Beta Blockers have
Intrinsic Sympathomimetic Activity = ISA
Partial AGONIST @ B2-Ne Receptors
but is overidden by:
B1-NE blockade
ISA BB’s = PAP
Pindolol / Acebutolol / Penbutolol
What drug based on MoA?
- *Dilates Arterioles**
- no vein effect*
Metabolite: opens K+ channels in smooth muscle
of arterioles
Topical
- *MINOXIDIL**
- *Vasodilator**
Used for HAIR GROWTH = Rogaine
- may provoke ANGINA*
- *Headache / Sweating / Hirsutism**
What drug based on MoA?
- *Blocks AT2 Effects**
- antagonism of* AT2 type 1 receptor
- *ARBS**
- artans
NO COUGH, NO EFFECT ON BRADYKININ
clinically similar effects to ACE-i’s
- *ADR’s of BETA BLOCKERS**
- olols
BradyCardia / ↓cardiac contractility & excitibility
CNS = sedation / depression / sleep disturbance
REBOUND SYMPATHETIC STIMULATION
upon abrupt withdrawal = nervousness / tachycardia / HTN
HYPOGLYCEMIA
may exacerbate hypoglycemic episodes in insulin dependent diabetics
BetaBlockers may MASK hypoglycemia in diabetic pts
CCB ADR’s
- *CARDIAC DEPRESSION**
- *Greater in Non-DHP’s (Verapamil/Diltiazem)** > DHP’s (amlodipine)
- *BradyCardia / AV block / HF**
Short Acting Nifedipine = ↑risk of MI –> use LONG ACTING
Dizziness / Constipation / Peripheral Edema
FLushing / Nausea
Diazoxide
Class / MoA / ADR
Parenteral Vasodilator
- *Dilates Arterioles**
- not veins*
Opens K+ channels = stabilize smooth muscle membranes of arterioles
ADRs:
TachyCardia & Provokes ANGINA
Which Beta Blockers have
a-NE-blocking Activity
Stereoisomers have BOTH:
B-NE & a-NE antagonist activity
LABETOLOL
CARVEDILOL
What drug based on MOA?
Inhibits synthesis of AT2
↓vasoconstrictor activity
↓aldosterone release –> Na+ & H2O Retension
Blocks breakdown of BRADYKININ
↑bradykinin = vasoDilation
↓PVR
ACE INHIBITORS
↓BP by ↓PVR
CO & HR are UNCHANGED
no reflex tachycardia
ADRs of ARBS
- *similar to ACE-inhibitors**
- EXCEPT FOR:*
- *COUGH_ & _ANGIOEDEMA**
What drug based on MOA?
Direct agonist of a-adrenoreceptors @medulla:
↓sympathetic outflow / ↓BP / ↓Bradycardia
↑ParaSympathetic Tone
Initially, ↑BP
- > due to stimulation of peripheral a-receptors on arterioles
- when given IV = transient vasoconstriction*
- *CLONIDINE**
- *Guanzbenz** & Guanfacine
CNS-Acting Sympathoplegics
Special Uses for
BETA BLOCKERS w/ ISA
ISA BB’s = PAP
Pindolol / Acebutolol / Penbutolol
↓PVR –> ↓BP
LESS depression of CO & HR
due to greater B2 agonist > B2 antagonist activity
Useful in pts with:
Bradyarrhythmias & Peripheral Vascular Disease
do NOT use in patients with ANGINA