Examples
| Generic Name | Brand Name |
|---|
| alprostadil | Caverject |
| papaverine hydrochloride | |
| phentolamine mesylate | Rogitine |
Some doctors have these three medications mixed together by a
pharmacist. This preparation is often called Trimix.
You inject this medication into the side of the penis with a tiny
needle. The shots usually are not very painful, but you
may find the thought of injecting yourself uncomfortable. Less commonly, these
medications also may be available in an auto-injector in which the needle is
hidden, making them easier to use. You can adjust the dose of medication to
create an erection that lasts the desired length of time.
See an illustration of an
injection
.
Your doctor may give you a trial use of this medication while you
are in the office. This allows the doctor to see how well the medication works
for you, see whether you can use it properly, and check for adverse reactions, such
as a painfully long-lasting erection (priapism) or an allergic reaction.
How It Works
The medications are injected into the penis before sex to relax the
muscles that surround the blood vessels in the penis, increasing the
blood
flow into the penis and producing an erection that lasts 30 minutes to
an hour or longer. How long the erection lasts depends on how much medication
you inject.
Why It Is Used
These medications may be prescribed for
erection problems (erectile dysfunction) caused by
psychological or physical factors.
How Well It Works
A success rate of 85% has been reported from injections.1
Side Effects
Injections occasionally can result in a painful, prolonged erection
(priapism). Call your doctor if an erection lasts longer than 4 hours. If the
erection isn't relieved, it may damage tissues inside the penis.
Other side effects of injections may include:
- Bruising.
- Pain in the penis
(usually mild to moderate). Pain in the penis was reported by about 50% of
users in one study.2 Injecting the medication slowly
may help prevent pain. Only a few men stop using the medication because of
pain.
- Formation of scar tissue in the penis (fibrosis).
See Drug Reference for a full list of side effects. (Drug Reference
is not available in all systems.)
What To Think About
When investigating injections for erection problems, it is
important to include your partner in your decision.
These medications are less likely to be effective for men in whom
blood flow into or out of the penis is severely impaired.
They may cause problems for men with severe mental illness or for
those who would have difficulty giving the injection. If you have vision
problems, your partner can learn to give you the injections. Make sure your
partner is comfortable with helping you and with using injections.
These medications can be used by men who are taking medication to
prevent blood clots (anticoagulants, such as warfarin [for example,
Coumadin]).
Medications that are injected into the penis can be given no more
than every other day. Excessive use may cause scarring.
Some men may find the idea of self-injections unpleasant, or they
may find self-injections difficult to do. The use of an auto-injector, in which
the needle is hidden, may make the shots easier for some men to use.
Couples trying to have children may prefer injections over a vacuum
device, because the vacuum device blocks ejaculation.
Up to 60% of men stop using the medications.3 Reasons include:3, 4
- Partner relationship issues (being able to have
erections doesn't solve relationship problems).
- The mechanical
nature of the process, which interferes with spontaneity.
- Fear and
discomfort about giving an injection into the penis.
- Concern about
effects of long-term use.
- Development of tolerance to the
medication (which rarely happens).
- Development of scar
tissue.
Complete the
new medication information form (PDF)
(What is a PDF document?)
to help you understand this medication.