DRUG SAFETY IN PORPHYRIA
Drugs are the most common
factor precipitating the acute
attack of porphyria,
and it is essential that people
with the acute
porphyrias avoid taking
any drug which may induce
an acute
attack. (Of course,
if you have porphyria cutanea
tarda or erythropoietic protoporphyria,
you need not worry as these
conditions are not aggravated
by drugs.)
Our list contains
most drugs available in South
Africa at present. Note that
new drugs are constantly being
introduced, and the absence
of a drug from this list does
not mean that its safety can
be assumed.
The list is
presented in two ways: in
alphabetical order, and then
grouped together into common
indications for medication,
such as Asthma, Diabetes
etc. You can also print out
the entire list for your reference.
Check back from time to time
as we do update it as new
information becomes available.
GENERIC NAMES AND TRADE NAMES
Patients are
often confused by the names
of drugs. Every drug has two
names: an official or generic
name, and then one
or many trade
names which are the
names given to their products
by the different pharmaceutical
companies. Our drug lists
contain only generic names,
and it is therefore important
that you take the trouble
to read the package or to
ask your doctor or pharmacist
for the generic name before
consulting our list.
While we take every
precaution, we cannot accept
any responsibility for adverse
experiences arising from the
use of our lists.
See our disclaimer.
TOPICAL PREPARATIONS ARE SAFE
As a general
rule, all topical
preparations are safe. Thus
drugs which are applied directly
to the skin or into the ear
and eye, or used for gargling
without swallowing, are likely
to be safe. Our list omits
all agents used only by these
routes, and comprises only
those intended for systemic
use. Care should be taken
with rectal and vaginal preparations
and drugs which are inhaled,
as there may be significant
absorption.
KEY TO
STATUS TERMS
The following are
the status terms used in the
list.
| Use |
Likely
to be safe and may be
used freely. |
| Use,
but with caution |
Though
safety is not established
beyond doubt, the evidence
suggests that the drug
is unlikely to prove unsafe
in practice. It is usually
safe to take such a drug. |
| Use
only with extreme caution
and if no alternative |
There
is evidence to suggest
that the drug may yet
prove unsafe in practice,
or grounds to suspect
this may be so, or too
little evidence to suggest
that it may be safe. Such
drugs should only be used
if the expected benefits
strongly outweigh the
risks. If possible, use
an alternative. |
| Avoid:
high risk |
There
is evidence that such
drugs have precipitated
acute attacks in patients,
or other grounds for believing
that the risk of an acute
attack is high. |
| Unknown,
therefore avoid |
There
is too little evidence
to draw a conclusion,
and it is wisest to regard
the drug as potentially
hazardous and avoid its
use. |
CHOOSING
THE RIGHT DRUG
No porphyric
patient should take any medication
unless it is really necessary.
Many drug-related problems
involve medication which was
not strictly necessary in
the first place. Beware of
compound
medications: particularly
analgesics:one
of the ingredients may be
dangerous, even if the others
are safe.
When you do need
treatment, select drugs in the order
above. Before
you take any drug in the last three
categories, your doctor
must be sure that a real need for
the drug exists and that no safer
alternative is possible; you can
also expect to have the choice of
drug discussed with you, and you
should be properly informed of any
risks and give your consent before
you take any potentially risky medication.
THE NAPOS DRUG
DATABASE
The Norwegian
Porphyria Centre (NAPOS) has
designed an excellent database
(in English) detailing drug
safety in porphyria. We are
in the process of correlating
our own recommendations with
theirs, and we gratefully
acknowledge their work. Our
website contains a direct
link so that you can, if you
wish look up a drug on their
database directly.
CHOOSING
THE RIGHT DRUG FOR SPECIFIC
CONDITIONS
Please note
that information on prescribing
the right drug for some specific
conditions, e.g. hypertension,
malaria and family planning,
is available on the For professionals
pages.
HOW WILL
YOU KNOW IF YOU ARE REACTING
TO THE MEDICATION?
Symptoms of an incipient
acute attack
If you develop significant
abdominal pain, that is, deep, gnawing
pain and discomfort in your abdomen,
you need to contact your doctor.
This may be the first sign that
your porphyria is becoming more
active. Under these circumstances,
you must not take any more of the
medication until you have been absolutely
reassured that the pain is not due
to porphyria. If the symptoms are
compelling, then you should have
your urine tested for PBG,
but you should not wait for a result
before contacting your doctor.
Other symptoms
Any other symptom—heartburn,
dizziness, nausea, drowsiness etc.—is
unlikely to be as a result of porphyria.
Most drugs have side-effects, and
people with porphyria are no more
prone to these than are normal people.
Under these circumstances you may
safely continue our medication,
provided the side-effects are not
in their own right sufficiently
severe to force you to stop treatment.
WHEN YOU ARE FORCED TO TAKE
A POTENTIALLY DANGEROUS MEDICATION
Under some circumstance
your doctor may be forced
to prescribe treatment which
is not definitely safe, e.g.
if you develop TB or cancer.
Provided you and your doctor
are careful, this seldom gives
problems. You need to choose
the safest alternative, take
your medication as prescribed,
avoid taking other and unnecessary
potentially dangerous substances
at the same time (including
alcohol and cannabis), and
inform your doctor immediately
if you develop pain.
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