Description
Quadmix Injection is a custom-compounded intracavernosal injection (ICI) used to treat moderate to severe erectile dysfunction (ED), particularly in patients who are unresponsive to oral PDE5 inhibitors (e.g., sildenafil, tadalafil) or standard monotherapy agents like Alprostadil. The term Quadmix refers to the inclusion of four pharmacologic agents, each targeting different physiological pathways involved in penile erection.
- Alprostadil (Prostaglandin E1) – 10–40 mcg/mL: A potent vasodilator that increases intracellular cAMP, leading to relaxation of corpus cavernosum smooth muscle and enhanced arterial inflow.
- Papaverine Hydrochloride – 30–60 mg/mL: A non-selective phosphodiesterase (PDE) inhibitor that raises cAMP and cGMP, enhancing smooth muscle relaxation and vasodilation.
- Phentolamine Mesylate – 1–2 mg/mL: A non-selective alpha-adrenergic antagonist that reduces sympathetic vasoconstriction and supports arterial dilation and venous occlusion.
- Atropine Sulfate – 0.1–0.2 mg/mL: An anticholinergic agent that may reduce inhibitory parasympathetic tone and enhance erectile response in select neurovascular ED cases.
Mechanism of Action:
- Alprostadil activates prostaglandin E1 receptors → increases cAMP → smooth muscle relaxation.
- Papaverine inhibits PDE enzymes → increases cAMP and cGMP → prolonged vasodilation.
- Phentolamine blocks alpha-1 and alpha-2 adrenergic receptors → reduces sympathetic tone → improves blood retention in erectile tissue.
- Atropine blocks muscarinic acetylcholine receptors → may reduce parasympathetic inhibition → additional smooth muscle relaxation.
Together, these agents result in enhanced cavernosal blood inflow, maintenance of penile rigidity, and venous outflow restriction.
