QuadMix is administered as a penile self-injection, typically considered to be the most powerful class of anti-erectile dysfunction agents. While the components of QuadMix (Papaverine, Phentolamine, Prostaglandin E1, Atropine) are, on their own, indicated for a vast number of different conditions, the practice of bringing them together in concert to treat erectile dysfunction has become commonplace in sexual medicine. and is now considered the go-to treatment if a patient is not responsive to conventional PDE5 inhibitors such as Viagra or Cialis. QuadMix is used in the treatment of erectile dysfunction in males. QuadMix contains four drugs from complimentary classes designed to act synergistically, mixed into a sterile injection. They are:
A drug that causes blood vessels to expand (vasodilator); it produces an erection by allowing for increased blood flow to the penis. Papaverine interacts with adenylate cyclase resulting in increased cyclic adenosine monophosphate (cAMP) production, ultimately resulting in increased erectile capacity by relaxation of penile smooth muscle. This drug was one of the first effective therapies for erectile dysfunction administered by penile injection. Papaverine works by inhibiting phosphodiesterase nonspecifically, there are also multiple other mechanisms by which this drug acts to improve erectile capacity. The current body of medical literature has not established the predominant mechanism by which papaverine works. The multi-mechanistic manner by which this drug acts may be concentration dependent. Experimental data, performed in-vitro, displays papaverine acting to relax the penile arteries, the cavernosal sinusoids, and the penile veins. Experiments carried out in dogs display papaverine’s ability to decrease the resistance to arterial inflow while also increasing the resistance to venous outflow. Papaverine’s ability to decrease resistance to venous outflow has been replicated in clinical studies. A veno-occlusive mechanism may be responsible for the aforementioned findings.