Editing Priapism (section)

===== Intracavernosal α-adrenergic injection =====
* </span>'''<span style="color:#ff0000">MOA of α-agonists: vasoconstrictors (cause smooth muscle contraction of the cavernous artery and arterioles)'''
* </span> '''<span style="color:#ff0000">Options: phenylephrine''', etilefrine, ephedrine, epinephrine, norepinephrine, metaraminol)
**<span style="color:#ff0000">'''Phenylephrine is the'''</span> '''<span style="color:#ff0000">α-agonist of choice in ischemic priapism</span>'''
***'''Has less systemic side effects compared to other alpha-agonists due to its relatively selectivity for α1-adrenergic receptors with minimal β-mediated ionotropic and chronotropic cardiac effects'''
***Use in this context is off-label

====== Technique<span style="color:#ff0000">[https://pubmed.ncbi.nlm.nih.gov/35536142/ ★]</span> ======
*The optimal regimen for phenylephrine dosing, frequency, and method of administration has not been clearly defined
** '''<span style="color:#ff0000">Phenylephrine diluted in normal saline to a concentration of 100-500 mcg/mL</span>''' (0.1-0.5 mg/mL) (optimally premixed by pharmacy to minimize risks of miscalculation/overdose)
***Dilute 10mg/mL vial of phenylephrine with 19mL of normal saline to get 10mg/20mL volume = 0.5mg/mL = 500mcg/mL
** '''Administered intracavernosally (not subcutaneously)'''
** '''Administered laterally (3 or 9 o’clock position) near the base of the penile shaft'''
*** Small needles may be used (e.g., 27G) if not aspirating
** '''<span style="color:#ff0000">Doses administered ≥5 minutes apart'''
**'''<span style="color:#ff0000">May be continued for up to 1 hour'''
*** '''<span style="color:#ff0000">If the erection persists despite repeated attempts with injections and aspiration/irrigation > 1 hour,  proceed with more definitive therapy (i.e., shunting procedure).''' 
** '''In cases where the combination of phenylephrine and aspiration/irrigation are performed, aspiration should precede phenylephrine administration to permit fresh, oxygenated blood to fill the corpora and potentially improve the yield of phenylephrine administration'''
***'''The penis is aspirated between successive injections by tightly pinching the shaft at the penoscrotal junction, just below the site of needle insertion'''
** '''<span style="color:#ff0000">No recommendations can be made about maximum safe dosage.</span>''' 
***'''Although there is no upper limit to the number of injections which may be performed, injections should be stopped if blood pressure changes are detected.''' 
****'''<span style="color:#ff0000">Hypertensive stroke has been reported as a complication of cumulative administration of 2 mg</span> [20mL if 100 μg/mL; 10ml if 200 μg/mL]'''

====== <span style="color:#ff0000">Adverse effects of intracavernous sympathomimetics</span> ======
# '''<span style="color:#ff0000">Hypertension (most common)</span>'''
# '''<span style="color:#ff0000">Reflex bradycardia (most common)</span>'''
# '''<span style="color:#ff0000">Tachycardia</span>'''
# '''<span style="color:#ff0000">Irregular cardiac rhythms</span>'''
#'''<span style="color:#ff0000">Headache</span>'''
# '''<span style="color:#ff0000">Dizziness</span>'''

* '''Patients receiving intracavernosal injections with phenylephrine should be monitored for blood pressure and heart rate<span style="color:#ff0000">[https://pubmed.ncbi.nlm.nih.gov/35536142/ ★]</span>'''
** Blood pressure and heart rate monitoring seems especially prudent in patients with a history of cardiovascular disease, hypertension, prior stroke, and those using medications such as monoamine oxidase inhibitors (MAOIs).

====== <span style="color:#ff0000">Contraindications</span> ======

* '''<span style="color:#ff0000">Relative: Use in patients on Monoamine Oxidate Inhibitors (MAOIs) (e.g. isocarboxazid, phenelzine, selegiline, tranylcypromine)</span>'''
** '''No reports of toxicity when used for priapism in males using MAOI'''
**Potentiation of phenylephrine effects by prior administration of MAOI is most significant with use of oral phenylephrine, which is dissimilar from intracavernosal administration.
**Gradual dose escalation may be reasonable when treating priapism in men using these medications.