Block 5: ED Flashcards
How do you diagnose ED?
- Failure to ejaculate
- Premature ejaculation
- Inability to achieve orgasm
- Loss of desire or libido
What are the types of ED dysfunction?
- Increased libido
- Erectile dysfunction (impotence)
- Delayed ejaculation
- Retrograde ejaculation
- Infertility
What is the MOA of ED?
- Sexual stimuli enhances production of nitric oxide which in turn stimulates production of cGMP
- cGMP is vasodilatory-relaxes smooth muscle in the arteries-enhances arterial flow to the penis
- Catabolism of cGMP is mediated by phosphodiesterase.
What are the types of ED?
Organic erectile dysfunction
Psychogenic erectile dysfunction
What is psychogenic ED?
Not receptive to sexual stimuli
What are the causes of ED?
What are the pharm tx?
PDE-5 Inhibitors:
* Viagra (Sildenafil)
* Levitra (Vardenafil)
* Cialis (Tadalafil)
Testosterone
Self-Injection Technique: Alprostadil, Caverject®
Urethral Suppositories: Alprostadil, Muse® (Medicated Urethral System for Erections)
Vacuum Devices
What is vacuum erection device?
CI
Vacuum pressure draws blood into the corpora cavernosa
CI: Sick cell, priapism
Tx of testosterone replacement?
Testosterone does not directly treat ED, but it improves libido which may be a cause of ED
ADR of testosterone?
Sodium (fluid) retention, which can cause weight gain, or exacerbate HTN, congestive heart failure, and edema
What is fist line for ED?
Silver Falls High School
What is the MOA of PDE5 inhibitors?
- Selective inhibition of phosphodiesterase (PDE)-type 5 isoenzymes
- Inhibits catabolism of cGMP
- cGMP = vasodilatory
Patient counseling PDE5 inhibitors?
- patients must engage in sexual stimulation (foreplay) for the best response
- sildenafil and vardenafil should be taken on an empty stomach
- pts who do not respond to the first dose should continue with the PDE-i for at least 5-8 doses before failure is declared, as increasing success rates are reported with sequential dose administration
How should vardenafil and sildenafil be taken?
Both have about 1-hour onset, short duration and PO absorption delayed when the drug is taken within 2 hrs of a fatty meal
how should tadalafil be taken?
Onset of 2 hours, prolonged duration (up to 36 hrs), and food does not affect absorption
ADR of PDE5is?
HA, facial flushing, dyspepsia, nasal congestion, DZ
Visual effects –loss of clor discrimination/ hearing loss(sildenafil, vardenafil)
Back pain/myalgia (tadalafil)
Priapism
What are the tx for PDE5i?
- Ice packs, hydration, phenylephrine injections, surgery
- If not treated can lead to permanent ED
What are the DDI of PDE5i?
- Nitrates
- a blockers (terazosin and doxazosin)
Alprostadil
MOA
PGE1: stimulates adenyl cyclase, resulting in increased prod. of cAMP-smooth muscle relaxation of the arterial blood vessels/sinusoidal tissues in corpora
Patient counseling of aprostidil injection?
- administered 5-10 min. before intercourse
- to avoid a/e pts should receive no more than 1inj. per day and 3 inj. per week
ADR of intracavernosal alprostidil?
- Cavernosal plaques or areas of fibrosis
- Penile pain
- Priapism
- Inj site hematomas and bruising
ADr of intraurethral alprostadil?
- Urethral injury and pain
- Priapism
- Female vaginal burning and pain
Counseling for intraurethral alprostadil?
- Patient should void first
- patient holds penis and with the other hand inserts the intraurethral applicator 0.5 inch into the urethra.
- drug pellet is then pushed into the urethra.
- penis should be massaged to enhance drug dissolution and drug absorption
What is penile prosthesis?
Malleable prostheses consist of two bendable rods that are inserted into the corpora cavernosa. patient appears to have permanent erection and is able to bend penis into position at the time of intercourse
