3rd Annual Jefferson Urology Symposium: Men’s Health Forum

© The Canadian Journal of Urology TM : International Supplement, August 2020 commonly used injectable agents administered either as monotherapyor combination therapy in clinical practice. ICI is an alternative treatment for oral ED therapy with better satisfaction rates up to 94%andminimal systemic side effects. 27,28 However, ICI therapy presents some barriers for patients or partners. Its administration is more challenging compared to other options. Also, it causesmore anxietydue to the fear of injecting the penis. The first dose should be administrated in the clinic to determine the optimal dosage to achieve a good erection that does not last longer than 1 hour. Additionally, a man and his partner may feel more confident with the method and facilitate adherence to the treatment after a self-injection training session. The most commonly used medication for ICI is PGE1, also known as alprostadil, which is the only FDA approved medication to be used for ICI. The overall satisfaction rate of alprostadil monotherapy for ICI approximates 80% with dose titration from 1.25 to 20 m g. 29 Combination therapies are also recommended by clinical guidelines as an alternative to monotherapy to achieve higher efficacy and a more favorable side-effect profile by using lower dosages of each agent. Alprostadil can be combined with papaverine and phentolamine and called “tri-mix.” When two medications are combined, it is called “bi- mix.” Acombination of papaverine and phentolamine is widely used as a bi-mix for injection even though it is not FDAapproved for ICI in ED treatment. Papaverine is a nonspecific phosphodiesterase inhibitor and increases intracellular levels of both cAMP and cGMP. Phentolamine is an alpha-adrenergic receptor blocker and reduces sympathetic tone in the penis, thereby opposing vasoconstriction. Papaverine was the first medication discovered to be used for ICI. However, it is rarely used as monotherapy due to lower overall efficacy and higher AEs such as corporal fibrosis, high potential of priapism, and liver toxicity. Phentolamine also shows limited efficacy as a monotherapy. It is usually combined either with alprostadil or papaverine. Bi-mix utilizes the synergistic actions of cAMP elevation by alprostadil (20 m g/mL) with phosphodiesterase inhibition by papaverine (30 mg/ mL) or alpha-adrenergic blockage by phentolamine (0.5 mg/mL), resulting in a response rate of 68.5%. 30 In combination with three mediations called tri- mix, and its overall success rate reported 72.6%. 31 Concentrations of each component vary widely in the literature, but ratios of 12-30 mg papaverine: 10-20 μg alprostadil:1 mg phentolamine are common. 8 Patients should be counseled regarding the potential AEs of ICI therapy. The most serious AE is priapism. Several studies reported a mean rate 31 The medical and surgical treatment of erectile dysfunction: a review and update of 6.3% for prolonged or painful erections and 1.8% for priapism using alprostadil, 8.9% for prolonged or painful erections and 5.5% for priapism using bi- mix (papaverine and phentolamine), and 2.8% for prolonged or painful erections and 3.1% for priapism using tri-mix. 8 Penile and genital pain is one of the common AEs with bruising. The highest rates of pain have been reported in patients who were using either alprostadil or papaverine as a monotherapy. Additionally, penile fibrosis, plaques, and penile deformities have been reported with the use of ICI. Clinical guidelines suggested that clinicians should document the preexistence of any of these conditions before initiating ICI. Regular patient follow ups are essential for assessing the progression or onset of these conditions. The contraindications of the use of ICIs include Peyronie’s disease, a history of recurrent priapism, and bleeding disorders. Penile prosthesis implantation The penile prosthesis is a surgically implanted device that has beenused for EDtreatment over the last 40years. The device has undergonemultiple improvements over the years to minimize device failure and infection risk and optimize device function tomaximize the patient’s and his partner’s satisfaction. There are a variety of forms of penile prostheses, including malleable and inflatable devices. The malleable device contains two semi-rigid cylinders that are implanted into the penile corpora. It is an ideal option for patients who are physically handicapped with poor hand dexterity. While malleable device has poor concealment, it has lower mechanical failure rates due to its minimal components. 32 There are two types of implantable penile prosthesis (IPP) that consist of either two or three pieces. The two-piece IPP can provide full rigidity. However, the cylinders prefill with fluid due obviating the need for a reservoir, which achieves some degree of tumescence. It can be a good option for patients with the hostile pelvis. The three-piece inflatable penile prosthesis device consists of two fluid-filled cylinders that are implanted into the penile corpora, along with a pump that is placed in the scrotumand a fluid reservoir that is situated in the abdomen. It is considered a better option than the malleable prosthesis producing better penile rigidity and more flaccidity that closely replicates normal erection. The patient satisfaction rates of IPP are 86% that is higher than oral medication or ICI [guideline]. The 5 and 10 year overall survivals of modern prosthetics are estimated to be 90.4% and 86.6%, respectively. 33