Ototoxic Drugs Exposed
We've been learning a lot about the impact of various drugs on
hearing loss, but the information has been scattered and not very
accessible. Dr. Neil Baumann's SHHH workshop entitled "Ototoxic
Drugs Exposed" did a wonderful job of consolidating this
information. Here's the report on this workshop from Cheryl Heppner,
Executive Director of NVRC.
~~~~
Dr. Neil Bauman's workshop on Ototoxic Drugs was standing room only,
and many of those in the room had personal experience with hearing loss
due to ototoxic drugs. Bauman's presentation was wide-ranging and he
answered numerous questions from the audience.
The FDA warns that there is no such thing as a completely safe drug.
All have risks; some are worse than others. Unfortunately, doctors are
often too busy treating you to read books that would provide information
about drugs.
Eighty three percent of the top 200 drugs prescribed in the year 2000
can be ototoxic. An ototoxic drug is one that can damage your ears in a
number of ways -- causing damange to the cochlea, the vestibular system,
balance, the nerve going to the brain, the ear canal, inner ear, etc.
The most common ototoxic effect is tinnitus, causing you to hear a
sound such as ringing, roaring, clicking, buzzing, hissing, clanging,
chirping, buzzing, glass breaking, an owl hooting, etc. Dr. Bauman knows
of 400 drugs known to cause tinnitus. He queried those in the audience
to see how many have this condition and half of them raised their hands.
Auditory hallucination is another side effect where you hear things
that are not there. Dr. Bauman feels it's a product of our damaged ears.
Dr. Bauman shared that his hearing loss is hereditary. Ten years ago
he took a coping skills course, and later taught speechreading and
coping. He set out to write a book that would tell everything you need
to know as a person with hearing loss. One section of the book was
intended to deal with ototoxic drugs, but as he did more research it
grew to 640 pages. It ended up with its own book, "Ototoxic Drugs
Exposed".
Doctors think that the incidence of hearing loss caused by drugs is
rare. Typically hearing is tested from 300 Hz to 3,000 Hz, but our
hearing goes up to 24,000 Hz. Special equipment is needed to test the
higher frequencies. Dr. Baumann has "reverse slope" hearing
loss; he can't hear people close to him, but he can hear those speaking
in the back of the room. He thinks we should be given testing for the
higher frequencies. While professionals say speech is at 8,000 Hz, more
sounds go up as high as 20,000 Hz. Dr. Bauman would love to see a
comprehensive audiogram required before a patient is given any drugs.
Most of the early damage from drugs is at the highest frequencies you
can hear. If the hearing loss could be caught when it occurs at the
highest frequencies, you would at least know you're sensitive to the
drug and could prevent more damage.
Once drugs are released, drug companies don't do further studies.
Some drugs cause problems with discrimination. You hear, but what you
hear is garbled. Drugs can also cause hyperacusis, where normal sounds
seem too loud. Hyperacusis is a side effect of a lot of common
antidepressants.
Another warning sign can be a feeling of fullness in your ear. It may
feel stuffed or blocked. When you lose hearing, it often feels this way.
When you get sound back, that feeling goes away, unless it was caused by
a condition such as a cold.
Drugs affect the vestibular system. Dizziness can sometimes be caused
by ototoxic drugs. Dr. Bauman's book covers only dizziness in
combination with hyperacusis. Vertigo, where the room appears to spin or
you feel like you are spinning, is also a side effect of ototoxic drugs,
as is ataxia. The latter causes a staggering gait because you cannot
keep your balance. Another condition that can be caused by ototoxic
drugs is nystagmus. With this condition, if there is damage to your
ears, the eyes jerk horizontally and involuntarily.
Drugs can also cause central processing disorders, the production of
too much ear wax, ear pain (otalgia) and otitis media (middle ear
infections).
As soon as you sense one of these side effects may be happening, you
should contact your doctor to discuss it.
Certain people have higher risk for ototoxicity. Dr. Baumann listed
24 risk factors. The list includes people over age 60 or very young or
unborn children. Those with certain genetic factors seem to be more
sensitive to aminoglycoside antibiotics. Vancomycin, for example, can be
taken without problems by some people, while others will have hearing
loss. It's estimated that about 1/3 of the population has this genetic
defect.
If you already have sensorineural hearing loss, you are predisposed
to be at risk for more hearing loss. Previous ear damage from noise
calls for caution. Aminoglycoside antibiotics can take a long time to
get out of the body, so even months after you stop taking them, you can
be at a higher risk of hearing loss from noise exposure. You should
caution your audiologist not to set your hearing aid levels too high
during this time.
There's a Chinese saying that the ears and kidneys are connected. If
you have problems with either your liver or kidneys, you are at higher
risk of drug ototoxicty.
If you previously found that you were sensitive to one drug that was
ototoxic, your ears are particularly sensitive and you may react to
others.
One disturbing finding was that doctors do not necessarily follow the
recommended dose for a drug. No tests have been done to show what
happens if you go beyond the recommended dose or use it longer than
recommended. The FDA in the past found that a lot of doctors prescribing
a particular drug were not following the recommended dose and that 85%
of prescriptions were written for doses greater than those recommended.
Some people experience problems with drugs when they are given an
adult dose. Unfortunately dosages are often based on total weight
instead of lean body weight.
There are a number of things you can do to reduce the risk of hearing
loss from drugs. Use the Physician's Desk Reference to learn more about
drugs. Drink lots of fluids. Don't take more than one ototoxic drug at a
time. Dr. Bauman has a fact sheet that lists 13 suggestions for reducing
risks.
Some drugs you can stop taking, but some you can't. Ask your doctor
what will happen if you stop. If you tell him you have a hearing loss he
may say "So?" You will have to explain that protecting your
remaining hearing is important to you.
Q: How can you know if hearing loss is age-related or drug-related?
A: They are related. Typically as you get older, you have taken more
drugs. Dr. Bauman believes hearing loss is often a combination of noise
and drugs, also it can be caused by reduced circulation.
Q: How is tinnitus different from auditory hallucinations? A:
Tinnitus is a simple sound that you hear repeatedly. An auditory
hallucination is more complex, like a piano playing up and down the
scale.
Q: Are there a lot of substitutes for ototoxic drugs? A: "Ototoxic
Drugs Exposed" has a table that lists ototoxic drugs and lists
others in the same class. There is also information about what other
drugs can be used that are not ototoxic.
Q: What about drugs that cause hearing loss but the doctor says
hearing will come back when you stop taking them? A: Doctors say hearing
loss from these drugs is temporary, but the hearing loss is not always
temporary.
Q: What about anti-inflammatory drugs? A: Lots of them are ototoxic.
Q: Is aspirin ototoxic? A: Taking 6 aspirin per day will cause your
ears to ring. In some people, less than 6 will cause tinnitus. You have
to make up your mind whether you are willing to risk it.
Q: Prednisone is often prescribed for hearing loss. Is it on your
list? A: Prednisone can cause hearing loss. It is often used because
doctors don't yet know what is happening in your ear. For those with an
autoimmune ear disorder who took prednisone, 1/3 had no hearing loss,
1/3 lost their hearing and then had it come back, 1/3 took it and the
hearing loss stayed the same.
Q: Are hormones a problem? A: Dr. Bauman has heard from women taking
estrogen who said they experienced hearing loss.
Q: Is it possible for medication to affect the nerve or something
that would make a cochlear implant stop functioning? A: It's possible
but something else that may be of concern is loss of the balance system.
Be watchful for signs like vertigo.
Q: Has any research been done on foods to see if they are ototoxic?
A: Many people who reported hearing loss were coffee drinkers. Caffeine
definitely causes tinnitus.
Q: I experienced tinnitus from my blood pressure medication. What if
I can't take it? A: You can look at switching to one of the medications
for blood pressure that doesn't affect you.
Q: Are there drugs that are toxic to the eyes? My vision is very
important to me now that I have hearing loss. A: "Ototoxic Drugs
Exposed" has a list of 117 drugs that can damage the eyes. Of those
77 can also damage the ears.
Q: Would it help to keep a diary listing any new things happening
when you take a medication? A: That is a good idea.
Q: What about drugs for colds -- are they a concern? A: You have to
balance what a drug might do to what a cold might do. Work with your
doctor, but work from a position of knowledge. Try to live as healthy as
you can and take drugs only as needed.
For a more detailed article on ototoxic drugs, you can go to Dr.
Bauman's website: http://www.hearinglosshelp.com/ototoxicdrugs.htm
You can write to him at neil@hearinglosshelp.com
-- Cheryl Heppner, NVRC Executive Director, NVRC
