Chapter 53: Male Sexal Dysfunction & Benign Prostatic Hyperplasia Flashcards
ED
Erectile dysfunction (ED), also known as impotence
Persistent inability to achieve or sustain an erection suitable for sexual intercourse
Affects up to 30 million men
Commonly associated with chronic illnesses
Risk for ED increases with advancing age
4% of men in 50s
17% of men in 60s
47% of men 75 years or older
1st Lin x for ED
smoking cessation, exercise, looking for drugs that contrib
Tx for ED
Drugs
Oral agents
Nonoral agents
Psychotherapy
Surgical implantation of penile prosthesis
Oral agents for ED
Phosphodiesterase type 5 (PDE-5) inhibitors:
Sildenafil, vardenafil, and tadalafil
Originally CV drug
PDE-5 inhibitors ADR
Hypotension (See 8.4 drop in SBP and 5.5 drop in DBP), priapism, headache, dyspepsia, flushing, nasal congestion, diarrhea, rash, dizziness, mild transient visual disturbances, intensification of obstructive sleep apnea
Rare side effects:
Nonarteritic ischemic optic neuropathy
Sudden hearing loss
PDE-5 inhibitors drug interactions
Nitrates (could cause life-threatening hypotension)
Alpha blockers (can cause symptomatic postural hypotension)
Inhibitors of cytochrome P450 (CYP3A4) (can suppress metabolism)
PDE-5 inhibitors precautions
Drug should be used with caution by men with the following conditions:
Myocardial infarction (MI), stroke, and life-threatening dysrhythmia within the past 6 months
Resting hypotension (BP below 90/50 mm Hg)
Resting hypertension (BP above 170/110 mm Hg)
Heart failure
Unstable angina
Should not be prescribed for men taking nitroglycerin or any other drug in the nitrate family
Sildenafil (Viagra)
Only enhances normal erectile response in the presence of stimuli, No significant impact on men who do not have ED, Approved in 2005 as Revatio to treat pulmonary arterial hypertension
Available in 25-, 50-, and 100-mg tablets
Usual dose: 50 mg 1 hour before sexual activity
PDE-5 inhibitors II
Relaxes arterial and trabecular smooth muscle in the penis
Vardenafil [Levitra], Tadalafil [Cialis], Avanafil [Stendra]
Vardenafil [Levitra]
Prolongs QT interval; Dosing: 10 mg 60 minutes before intercourse; maximum dose 20 mg
Tadalafil [Cialis]
Effects last up to 36 hours; Dosing: PRN: 5 to 20 mg no more than once per day; Daily: 2.5 to 5 mg daily (if activity anticipated twice weekly)
Avanafil [Stendra]
Effects begin about 15 minutes after dosing and last about 2 hours; Dosing: 100 mg 30 minutes before intercourse
Papaverine (smooth muscle relaxant) plus phentolamine (alpha-adrenergic blocking agent)
Increases arterial flow and decreases venous outflow in the penis
Administration and dosing: Injected directly into the corpus cavernosum
Desired effect achieved with as little as 0.1 mL.
Usual concentration: 30 mg/mL paperverine and 1 mg/mL phentolamine
Adverse effects: Priapism, painless fibrotic nodules in the corpus cavernosum, orthostatic hypotension
Alprostadil (prostaglandin E1)
Increased arterial flow and decreased venous outflow in the penis
Administration and dosing:
Intracavernous: max 3 times per week; 5 to 40 mcg until erection achieved -Adverse effects: burning, priapism, penile fibrosis
Transurethral: Alprostadil pellets [Muse]; maximum twice in 24 hours; dosage determined in prescriber’s office; available in 125, 250, 500, and 1000 mcg
BPH
Nonmalignant prostate enlargement
Caused by excessive growth of epithelial (glandular) cells and smooth muscle cells
BPH s/sx
Urinary hesitancy, urgency, frequency
Dysuria
Nocturia
Straining to void
Postvoid dribbling
Decreased force and caliber of urinary stream
Sensation of incomplete bladder emptying
BPH tx
Surgery
Watchful waiting
Drug therapy
5-Alpha-reductase inhibitors (mechanical obstruction)
Finasteride
Dutasteride
Alpha1-adrenergic antagonists (dynamic obstruction)
5-Alpha-Reductase Inhibitors
Finasteride [Proscar]
Dutasteride [Avodart]
Finasteride [Proscar]
Most effective in patients with a very large prostate (mechanical obstruction)
Adverse effects
Decreases ejaculate volume and libido
Gynecomastia
Decreases levels of prostate-specific antigen (PSA) 30-50%
If patient on proscar for 6mon and PSA is not declined, look for cancer
Dutasteride [Avodart]
Similar to finasteride but with three differences:
Reduction in circulating dihydrotestosterone (DHT) is more complete
Harmful to a developing male fetus
Extremely long half-life (5 weeks)
Alpha1-Adrenergic Antagonists
Approved for treatment of benign prostatic hyperplasia (BPH):
Terazosin [Hytrin]
Doxazosin [Cardura]
Tamsulosin [Flomax]
Alfuzosin [Uroxatral]
Silodosin [Rapaflo]
Blockade of alpha1 receptors relaxes smooth muscle in the bladder neck (trigone and sphincter)
alpha 1 antagonists ADR
Tamsulosin [Flomax] and alfuzosin [Uroxatral]
Less likely to cause the effects of terazosin and doxazosin
Tamsulosin can cause abnormal ejaculation
Terazosin [Hytrin] and doxazosin [Cardura]
Hypotension, fainting, dizziness, somnolence, and nasal congestion
These drugs do not decrease PSA levels
Alpha 1 antagonists drug interactions
Exercise caution with other medications that lower blood pressure
Organic nitrates, antihypertensive drugs, PDE-5 inhibitors used for ED
Inhibitors of CYP3A4
Cataract surgery: “Floppy-iris syndrome”
Other drugs and supplements for BPH
Saw palmetto
Used widely
Effectiveness not supported
Tolterodine [Detrol]
Botulinum toxin
Diminish s/sx for 1 year
A patient has been prescribed sildenafil [Viagra] for erectile dysfunction. Which instruction should the nurse include in the teaching plan?
A. Take the medication on an empty stomach.
B. Drink plenty of fluids to prevent priapism.
C. Avoid taking nitroglycerin with this drug.
D. Constipation is a common adverse effect.
Answer: C
Rationale: Taking nitrates with sildenafil may result in severe hypotension. Sildenafil can be taken with or without food. Patients who experience priapism (an erection lasting longer than 4 hours) should contact their health care provider immediately.
A patient is taking finasteride [Proscar] for benign prostatic hyperplasia (BPH). The nurse should explain that this medication has what effect?
A. Decreases the size of the prostate gland
B. Relaxes smooth muscle of the prostate gland
C. Reduces the risk of prostate cancer
D. Improves sexual performance during intercourse
Answer: A
Rationale: Finasteride [Proscar] promotes the regression of prostate epithelial tissue and decreases the size of the mechanical obstruction.
The nurse should instruct a patient prescribed sildenafil [Viagra] to avoid taking this medication with what?
A. Grapefruit juice
B. Milk
C. Crackers
D. Eggs
Answer: A
Rationale: Inhibitors of CYP3A4 (e.g., ketoconazole, itraconazole, erythromycin, cimetidine, saquinavir, ritonavir, and grapefruit juice) can suppress metabolism of sildenafil, thereby increasing its levels.
