| Combination of | |
|---|---|
| Alprostadil | prostaglandin |
| Papaverine | vasodilator |
| Phentolamine | alpha blocker |
| Clinical data | |
| Routes of administration | injection, intraurethral, topical |
| Legal status | |
| Legal status |
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| Identifiers | |
| ChemSpider |
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Trimix is a prescription combination drug containing alprostadil, papaverine, and phentolamine. It is used to treat erectile dysfunction. [1] [2] [3]
Trimix is available in several different formulations, including a gel that can be used topically, a gel that can be administered into the urethra, and an injectable form that is administered via intracavernosal injection (an injection at either side, not the base, of the penis). [2] [4] [5] [6]
Adverse effects from injecting Trimix may include pain, fibrosis, hematoma, and priapism (a prolonged erection of the penis). [3]
Trimix is a combination of three drugs: alprostadil, papaverine, and phentolamine. These medications work in combination to increase blood flow to the penis, resulting in an erection. [1] [2] [3] Alprostadil is a prostaglandin vasodilator that allows more blood to flow into the area by relaxing the smooth muscle in the blood vessels of the penis. [3] [7] Papaverine is a smooth muscle relaxant that acts by increasing blood flow to the penis. [3] [8] Phentolamine is an alpha blocker that relaxes blood vessel muscles, allowing more blood to flow to the penis. [3] [9]
While the active drugs in Trimix have all been individually approved by the U.S. Food and Drug Administration (FDA), Trimix as a combination drug has not been approved by the FDA and is only available from compounding pharmacies. [1] [3] [10] Trimix is typically prepared by the compounding pharmacy in a sterile environment and then frozen. [11] The compound is stable for up to six months while stored frozen and for one month if stored refrigerated beginning at the time of manufacture. [12]
The vasoactive potential of phentolamine was discovered in 1978, with early animal studies suggesting effective blockade of the epinephrine pressor response and a smaller sympatholytic effect (63). An alpha-adrenergic antagonist with equal affinity for α1 and α2 receptors, monotherapy with phentolamine has been disappointing. It is hypothesized that although intracavernous injection of phentolamine increases corporal blood flow, a concurrent increase in norepinephrine prevent sinusoidal relaxation.