Chapter 13: Adrenergic Drugs Affecting the ANS - Prototype Drugs Flashcards
Prototype Drugs
1
Q
Adrenergic Agent (Sympathomimetics) Prototype Drug
A
phenylephrine
2
Q
phenylephrine Therapeutic and pharmacologic Class
A
- Therapeutic Class: Nasal decongestant; mydratic drug; antihypotensive
- pharmacologic Class: Adrenergic drug (sympathomimetic)
3
Q
phenylephrine Actions and Uses
A
- stimulates the SNS directly/indirectly - (anticholinergic responses)
- primary use: depends on receptor activated
- Alpha 1 receptors: nasal congestion, hypotension, dilation of pupils for eye exam
- Alpha 2 receptors: Hypertension
4
Q
phenylephrine Admin Alerts
A
- Route: Intranasal, ophthalmic, IM, SubQ, IV
- Parenteral admin can cause tissue injury with extravasation
- ophthalmic drops - may damage soft contact lenses and can cause narrow-angle glaucoma secondary to their mydriatic effect
- intranasal can cause burning of the mucosa and rebound congestion if used for prolong periods
Pregnancy category C
5
Q
phenylephrine Adverse Effects
A
- Tachycardia, HTN, dysrhthmias, CNS excitation and seizures, dry mouth, N/V, anorexia
- lacks beta-adrenergic agonist activity - produces relatively few cardiac side effects at therapeutic doses
- high doses can cause reflex bradycardia d/t elevation of BP caused by stimulation of alpha 1 receptors
- anxiety, restlessness, and tremor may occur d/t stimulation effect on CNS
- patients with hyperthyroidism may experience a severe increase in basal metabolic rate, resulting in increased BP and ventricular tachycardia
6
Q
phenylephrine Black Box Warning
A
- Severe reactions, including death, may occur with IV infusion even when appropriate dilution is used to avoid rapid diffusion
- restrict IV use for situations in which other routes are not feasible
7
Q
Phenylephrine Contraindications
A
- Acute pancreatitis
- heart disease
- hepatitis
- narrow-angle glaucoma
8
Q
Phenylephrine Interactions
A
- use with MAOIs may cause HTN crises
- increased effects may occur with tricyclic antidepressants, ergot alkaloids, and oxytocin
- inhibitory effects occur with alpha blockers and beta blockers
- incompatible with iron preparations (ferric salts)
- may cause dysrhythmias when taken in combination with digoxin
9
Q
phenylephrine Treatment of OD
A
- OD may cause tachycardia and HTN
- treatment with an alpha blockedr such as phentolamine may be indicated to decrease blood pressure
10
Q
Adrenergic-blocking Agents (sympatholytics) Prototype Drug
A
prazosin
11
Q
Prazosin Therapeutic and pharmacologic class
A
- Therapeutic class: Antihypertensive
- Pharmacologic class: Adrenergic-blocking drug
12
Q
Prazosin Action and Uses
A
- inhibits the SNS
- majore action is a rapid decrease in peripheral resistance that reduces BP
Used for:
- HTN, dysrhythmias, angina, HF
- BPH
- Narrow-angle glaucoma
- most common use is in combination with other drugs such as beta blockers or diuretics in the pharmacotherapy of HTN
13
Q
Prazosin Adverse Effects
A
- Dizziness, drowsiness, headache, loss of energy and strength, palpitations, dry mouth
- Tends to cause orthostatic hypotension d/t alpha 1 inhibition in vascular smooth muscle
- reflex tachycardia may result from the rapid fall in BP
- tolerance to prazosin’s antihypertensive effect may occur
- has little effect on cardiac output or heart rate, and it causes less refelx tachycardia than some other drugs in this class
- alpha blockade may cause nasal congestion or inhibition of ejaculation
- monitor urinary hesitancy, incomplete bladder emptying, interrupted urinary stream
14
Q
Prazosin Admin Alerts
A
- Route: PO
- Give a low first dose to avoid severe hypotension
15
Q
Prazosin Interactions
A
- concurrent use of antihypertensives and diuretics result in extremely low BP
- avoid alcohol
- do not use saw palmetto or nettle root products - hypotensive response
