Question

Alpha2 Agonists: Central -pharmacodynamics and pharmacotherapeutics (mainly look at Clonidine including clinical use and dosing, off label uses and patient ed.) Alpha, Antagonists-pharmacodynamics and pharmacotherapeutics (what does it do and what do you use this drug for?)-Example- antihypertensive, BPH, postural hypotension Beta-adrenergic Antagonists (Blockers)- pharmacodynamics and pharmacotherapeutics All sections especially clinical use and dosing and withdrawal of beta blockers and patient education. Interaction with clonidine and beta blockers. Combined Alpha and Beta Adrenergic Antagonists -pharmacodynamics and pharmacotherapeutics Muscarinic Agonists-pharmacodynamics (what is this and what do we use it for) Cholinesterase Inhibitors- pharmacodynamics, clinical use and dosing, and toxicity Cholinergic Blockers pharmacodynamics (what is and what do we use it for)

Answer 1

1. Alpha 2 agonists pharmacodynamics and pharmacotherapeutics :-

Inhibition of neurotransmitter release, decreased production of aqueous humor, analgesia.

- stimulation of central-presynaptiuc alpha-2 receptors cause a decrease in sympathetic outflow; vasodilation and bradycardia occur without the possibility of reflex tachycardia

Example :

# Clonidine

- A-2 agonist: stimulation of cps a-2 receptors cause a decrease in sympathetic outflow; vasodilation and brady occur without the possibility of reflex tachy

- hypertension, severe pain, opiate withdrawal

- high lipid soluble, 50% eliminated y kidneys

- CI: breast feeding (risk of hypotension and bradycardia for the baby)

- AE: hypotension, drowsiness, constipation, xerostomia, erectile dysfunction

- DI: antihypertensive agents. CNS depressants, drugs that cause bradycardia, drugs having alpha -1 agonist or alpha -2 antagonist activity

- Cautions: reduce gradually to avoid severe rebound hypertension, CVD, MI, severe heart failure, occupations require alertness, renal impairment, pregnancy category C.

2. Alpha 1 antagonist pharmacodynamics and pharmacotherapeutics :-

Activation of Alpha 1 receptors causes blood vessels to constrict

Pharmacology -

Prevent activation of alpha 1 receptors, leading to relaxation of blood vessels. These drugs also happen to relax muscles in the bladder neck and prostate, which is why drugs from this class can also be used to treat enlarger prostate (BPH)

Indications -

Hypertension, Benign Prostatic Hyperplasia (BPH)

Side Effects -

Orthostatic Hypotension (blood pressure drops quickly upon changing from sitting position to standing), Dizziness, Syncope

3. Beta - adrenergic antagonists - pharmacodynamics and pharmacotherapeutics :-

DRUGS THAT HELP LOWER BLOOD PRESSURE, LOWER PULSE RATE AND CARDIAC OUTPUT.

ALSO USED TO TREAT MIGRAINE HEADACHES AND OTHER VASCULAR HEADACHES.

CERTAIN PREPARATIONS OF THE BETA BLOCKERS ARE USED TO TREAT GLAUCOMA AND PREVENT MYOCARDIAL INFARCTIONS.

THESE DRUGS ACT BY BLOCKING THE SYMPATHETIC VASOMOTOR RESPONSE.

Examples :-

1. ACEBUTOLOL

BETA ADRENERGIC BLOCKER

BRAND/TRADE NAME: MONITAN, RHOTRAL, SECTRAL

ACTION/USE:

- Act by blocking sympathetic vasomotor response

2. ATENOLOL

BETA ADRENERGIC BLOCKER

BRAND/TRADE NAME: TENORMIN, APO-ATENOL, NOVA-ATENOL

ACTION/USE:

- Act by blocking sympathetic vasomotor response

3. ESMOLOL

BETA ADRENERGIC BLOCKER

BRAND/TRADE NAME: BREVIBLOC

ACTION/USE:

- Act by blocking sympathetic vasomotor response

4. PROPANOLOL

BETA ADRENERGIC BLOCKER

BRAND/TRADE NAME: INDERAL

ACTION/USE:

- Act by blocking sympathetic vasomotor response

# SIDE EFFECTS/ADVERSE REACTIONS

- ORTHOSTATIC HYPOTENSION (sudden BP fall when standing up or stretching)

- BRADYCARDIA

- NAUSEA/VOMITING

- DIARRHEA

- CONGESTIVE HEART FAILURE

- BLOOD DYSCRASIA

- MAY MASK HYPOGLYCEMIC SYMPTOMS

# NURSING CONSIDERATIONS

MONITOR THE CLIENT FOR CHANGES IN LAB VALUES THAT INDICATE NEPHROTIC SYNDROME:

- PROTEIN

- BUN

- CREATININE

MONITOR THE CLIENT'S BLOOD PRESSURE, HEART RATE AND RHYTHM.

MONITOR THE CLIENT FOR SIGNS OF EDEMA.

- Nurse should assess lung sounds for RALES and RHONCHI

TEACH THE CLIENT TO:

- RISE SLOWLY

- REPORT BRADYCARDIA, DIZZINESS, CONFUSION, DEPRESSION OR FEVER.

- TAPER OFF THE MEDICATION.

4. Combined alpha and beta adrenergic antagonist pharmacodynamics and pharmacotherapeutics :

# Pharmacodynamics of Alpha and Beta antagonists

alpha1 and non-selective beta blockade .Decrease BP thereby decreases cardiac workload

# Pharmacokinetics of Alpha and Beta antagonists

Absorption & Distribution: rapidly absorbed, epinephrine short duratoin.

Metabolism & Excretion: rapid first pass metabolism; bioavailability of 25%

Carvedilol - metabolized by CYP 2D6 and 2C9 .

Labetolol - not CYP meditated.

Excreted: Bile and feces.

Pharmacotherapeutics of Alpha and Beta antagonists -

- Precautions and Contraindications

epinephrine - used in emergencies; use with caution in people w/arrhythmias, heart disease, HTN, DM, or hyperthyroidism. CONTRAINDICATED: respiratory conditions sucha as bronchospasm.

NYHA class IV heart failure. -second or third degree heart block. -severe bradycardia

Use with caution in patients with liver disease - heavily metabolized by the liver.

elderly- monitor for adverse reactions: dizziness, increased risk for falls.

# Adverse Drug Reactions

fewer cardiac-related interactions.

lower incidence of CNS related reactions.

greater risk for orthostatic hypotension than with just BB.

# Food and Drug Interactions

Food: slows rate of absorption but not bioavailability. minimizes risk for postural hypotension. Labetalol should be taken consistently in regards to food. food increases absolute bioavailability.

Labetalol has produced a false-positive for amphetamine