Drug-Induced Priapism And Levitra (Vardenafil)

Priapism: What It Is

» Priapism is a prolonged (lasting four hours and more), undesired erection of the penis. It is not related to sexual arousal or sexual stimulation, and it is usually painful. Most practitioners view priapism a medical emergency because the condition can lead to sexual dysfunction, impotence or penile infection.

To understand the nature of priapism, it’s essential to grasp the mechanics of an erection that happens when the blood vessels in the penis relax and then open. ED drugs, such as Levitra, don’t initiate erection — a man needs some sort of sexual stimulation — but they certainly set the stage by boosting enzyme action in the erection chambers. As soon as the stage is set, the spongy tissues (corpora cavernosa) along the penis length become filled with blood and harden, while the veins carrying blood from the penis shrink.

PriapismSadly, in the small percentage of men prone to priapism, this system goes out of order, and they cannot get rid of the erection once it is in place. Long story short, blood can flow in, but it cannot flow out.

If an erection continues for 12 hours or longer, the tissue in the erection chambers can be irreversibly damaged, and this can lead to serious erectile dysfunction. Such men may not be able to get a full erection in the future, only a partial erection.

The Causes Of Priapism

A healthy erection happens in response to sexual stimulation. Priapism happens when certain parts of the system — the blood vessels, nerves or smooth muscles — modify normal blood flow. As a result, the erection persists. Although the underlying reasons of priapism are not easily defined, certain conditions can play a role.

Medical conditions that can lead to priapism:

  • Haematological disorders (g., leukemia, sickle cell disease, multiple myeloma, thalassemia and others)
  • Metabolic disorders (g., gout, amyloidosis)
  • History of malignancy (cancer involving the penis)

Trauma as a trigger of priapism:

  • Direct trauma to the penis, perineum, or pelvis
  • Injuries of spinal cord

Medications (selected drugs enlist priapism as one of the side effects):

Medications recognized as increasing the risk of priapism:

  • Antidepressants and antipsychotics (risperidone [Risperdal], olanzapine [Zyprexa], clozapine, quetiapine, chlorpromazine, sertraline, citalopram, escitalopram, fluoxetine, lithium, pericyazine, trifluoperazine)
  • Antihypertensive drugs (propranolol, hydralazine)
  • Blood thinners (warfarin, heparin)
  • Recreational drugs (alcohol, cocaine, cannabis, methamphetamine, ecstasy, crystal meth)

Medications that have reported cases of priapism

  • Medicines injected straight into the penis in order to treat ED (alprostadil, phentolamine, papaverine, )
  • ED medications of PDE5 family (sildenafil [Viagra], tadalafil [Cialis], vardenafil [Levitra])
  • Medications used for ADHD treatment (methylphenidate, atomoxetine [Strattera])

Other factors:

  • A scorpion sting,
  • A spider bite
  • Other toxic infections

Priapism And Levitra

You are probably familiar with those warning messages at the end of Levitra, Viagra or Cialis advertising about seeking immediate help if you have an erection persisting for four hours or longer.

Rough statistics from the adverse event reporting system in the United States (AERS) regarding the erectile dysfunction (ED) drugs Viagra, Cialis and Levitra show a total number of 93 cases of prolonged erection of four hours and longer or painful erection lasting six hours and beyond (priapism) for the year of 2007 — 74 for Viagra, 16 for Cialis, and three for Levitra.

Specifically for Levitra, the statistics show that out of 8,524 patients who reported to have side effects when taking Levitra over the last 14 years (2003-2016), 58 people (0.68%) had priapism. 41% of those people were men of 50 years and older.

Viagra, the most popular ED drug, and Levitra`s PDE5 counterpart, has demonstrated a similar pattern in respect to the percentage of priapism cases in the total amount of side effect cases reported — the share constitutes 0.67%. 45% of Viagra takers who reported priapism were men of 50 years and older.

Cialis, the second most popular PDE5 drug, with 134 reported priapism cases out of 16,971 total reported side effect cases, over the same period of time, yields 0.79% share of priapism — only slightly more than for Viagra and Levitra.

As US data shows, PDE5 inhibitors are very unlikely to cause priapism in patients (less than 1% of all side effect cases reported), with less than 500 people affected over the last 14 years. We can safely extrapolate these statistics patterns on other geographies.

“Priapism caused by ED drugs is pretty rare,” says Dr. Ira Sharlip, spokesperson for the US Urological Association and professor of clinical urology at the University of California at San Francisco. He adds that — although he had taken care of priapism cases at the emergency room — it is really rare. After 10 years of prescribing PDE5 drugs to dozens of thousands of patients, Sharlip has never witnessed a case in his patient and therefore stopped discussing priapism as a potential complication altogether.

Signs And Symptoms

Ischemic (low-flow) priapism

Ischemic priapism represents a type of compartment syndrome when the pressure in the corpora cavernosa area of the penis compromises blood circulation in the cavernous tissues. The key symptom is ischemic corpora, as indicated by dark blood visible during the corporeal aspiration procedure. At least 95% of all priapism cases occur by an ischaemic mechanism. If left without treatment, the loss of oxygen can impair erectile tissues, and lead to the formation of scar tissues and a permanent sexual function loss.

Recurrent or stuttering priapism, a variety of ischemic priapism, is a very rare condition. It happens in men who have an inherited disorder known as sickle cell anemia characterized by the red blood cells of abnormal shapes. Sickle cells may block some blood vessels in the penis. As the name suggests, recurrent priapism represents recurrent episodes of prolonged erections and frequently includes episodes of ischemic priapism. In most cases, the condition emerges with short painful and undesired erections and might develop over time into more persistent and more prolonged erections.

Non-ischemic (high-flow) priapism

This form of priapism is usually not painful and may occur in an episodic fashion. A man suffering non-ischemic priapism may have a semi-rigid penis for hours. Because the blood circulation has not been impaired, non-ischemic priapism is unlikely to cause pain and often goes away on its own without triggering long-term damage.

Attributes of high-flow priapism include the following:

  • Adequate arterial blood flow
  • Well-oxygenated corpora
  • Marks of trauma: penetrating or blunt injury to the perineum or penis (straddle injury is often the trigger event)


Lab tests

  • Complete blood count (CBC test): to detect if the patient has leukocytosis, anemia, or thrombocytosis
  • Blood type and hold: exchange transfusion might be needed to treat the cause of ischemic priapism — sickle cell disease (SCD),
  • Plasma thromboplastin or activated partial thromboplastin time: priapism may require surgical procedure if medical treatment fails to succeed
  • Penile blood gas (PBG test) measurement: allows differentiating between high- and low-flow priapism
  • Toxicology test: to screen for drugs that can cause priapism.

Imaging diagnostics

  • Penile duplex Doppler ultrasonography: needed to identify and locate fistulas in non-ischemic priapism patients. This exam can also reveal an injury that might have triggered priapism.
  • Pelvic angiography: used to help confirm the location of fistulas
  • Computed tomography (CT) scanning or chest radiography or: applied for patients with medical history indicative of a malignant or metastatic condition

Other tests

Execute an electrocardiogram (ECG) for the patients older than 55 years of age, who are a possible surgical candidate or have a history of cardiac disease.

Ways To Treat Priapism

The treatment of low-flow priapism suggests multiple modalities and will be subject to how long the priapism has been in place and the results of the above-mentioned tests. The procedures are performed in a stepwise manner with a surgery called in as a last resort. Sadly, some of the treatments of priapism can potentially lead to erectile dysfunction later on.

Steps of treatments for low-flow priapism include:

  • Medication: A medication that inhibits blood vessels carrying blood into the penis (Intracavernosal phenylephrine [Neo-Synephrine]) is injected directly, with a small (29 gauge) needle, into the corpora cavernosa of the penis.
  • Aspiration of the corpora cavernosa area: blood is drained away from the penis with a 16 or 18 gauge needle and syringe. This intervention is followed up by saline irrigation and, when needed, by injection of an alpha-adrenergic agonist.
  • Surgery: If medical procedures are not successful, a surgical procedure that reroutes blood needs to be performed. A procedure called unilateral shunt is usually sufficient. The bilateral shunt is carried out if necessary (usually apparent within 10 minutes).

It is worth noting that persisting low-flow priapism can bring up some extent of cavernosal fibrosis and a consecutive loss of penile length. If this is the case, insertion of a penile prosthesis could be required to maintain penile length.

Treatment for non-ischemic Priapism

High-flow priapism usually clears off without any treatment. Since there is virtually no risk of impairment to the penis, your physician is likely to suggest a watch-and-wait approach. Applying ice packs along with pressure on the perineum area might be helpful in ending the erection.

What advice about priapism must be provided to patients?

Although priapism, in all likelihood, is a rather rare side effect, all male patients taking medications that may trigger priapism must be advised on its symptoms.

As a rule of thumb, priapism or any erection staying four hours or longer accompanied or not accompanied by sexual stimulation demands immediate medical attention to prevent potential complications.