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common injections, should the
acidity change to fall outside a fairly narrow range, significant pain
and tissue damage can result from use. With most eye drops, an expiry
date of one month after opening is accepted to minimize the potential
for dangerous bacterial contamination.
With any medication, once a specific threshold of
remaining active ingredient is passed, the medication can no longer be
relied upon to deliver accurate doses. This loss of reliability is
often exacerbated by the fact that the active ingredients can degrade
into various combinations of active, inactive or toxic breakdown
products. The common aspirin is for instance, known to react with
moisture to breakdown into salicylic acid, which is active, and acetic
acid, which is inactive and can lead to toxicity in excess.
While the expiry date provides a useful gauge of when to
stop using a medication, there are also many other factors that can
informally accelerate the expiry of a medication and make it dangerous
to use, chief among which is how the medication is stored. It is
oftentimes not just the medication that is affected by storage
conditions but also the storage container. Under inappropriate storage
conditions, certain containers can leech material into liquid
medication preparations, or medication particles can stick to the
container rather than remain separated. On average, a 10 degree rise in
temperature doubles the rate of chemical reactions that occur to a
medication product and can accelerate the rate of bacterial
contamination several fold. Just like an ice cream can simply melt or a
loaf of bread becomes mouldy much quicker if not refrigerated, many
medication products can easily expire much faster when not stored
appropriately.
With oral liquid and topical medications, potentially
dangerous changes associated with expiry can at times be detected by
color or consistency changes, component separations, altered smell or
taste (oral preparations). Should a suspicion of expiry arise, a
medication expert should be consulted regardless of whether or not the
labeled expiry date has been passed.
"Expiry" should also be understood to occur once a
supply of medications is no longer used appropriately for it's intended
purpose. Consultation with a medication expert is always advised to
prevent the inappropriate use of existing medication supplies.
Inappropriate use can often occur with self-medication and is harmful.
An unfinished supply of a previously used antibiotic may be tried to
treat a new infection that is actually untreatable by or resistant to
that antibiotic. This practice may not only delay recovery but can also
encourage the proliferation of "super bugs" that have resistance to
many antibiotics. Another incorrect purpose involves sharing
medications and this can be especially harmful if another is allergic
to the shared medication or a child or pet is medicated with an adult's
medication. Children often require dose adjustments to accommodate
their size while many human drugs are often unsuitable for pets. Even a
simple food like chocolate that we may enjoy can easily be toxic to a
pet dog.
Another mechanism whereby medication expiry is dangerous
occurs when an unfinished supply is used despite new information that
points to increased precautions associated with the medication or that
has led to it's recall. An example is obtaining pain relief from a
previous supply of a painkiller like Vioxx (rofecoxib) or Celebrex
(celecoxib) in spite of an existing heart condition that is now known
to relate to an increased risk of fatality under those circumstances of
consumption.
Expired medications that are kept instead of discarded
not only take up space but can actually discourage the appropriate use
of new supplies in the treatment of illness. A medication cabinet, if
not tended to regularly, could eventually contain more expired
medications than viable ones and this can lead to the accidental
consumption of an expired medication in place of a viable one. It is
definitely advisable to clear the medication cabinet of expired
medicaitons at least annually if not more often.
A further danger however, lies in how expired
medications are disposed of. Expired medications and pharmaceutical
byproducts can be harmful to the environment especially when they end
up in our rivers and drinking water supply. Hormonal compounds like
estrogen from birth control pills and patches as well as antibiotics
have been linked to being flushed by individuals and institutions into
sewage, draining largely unchanged and collecting in rivers and
streams, then returning in tiny amounts into drinking water. Traces of
antibiotics could worsen bacterial resistance while estrogens and other
steroids are known to change the reproductive characteristics of fish.
Even trace amounts of chemotherapy medications have emerged in tap
water and this could be severely detrimental to the unborn babies of
pregnant women who drink such water. The long-term impact on human
health of medications in our rivers and drinking water is as yet
unknown but no one would want to wait to find out. We can all play our
part by inquiring on and using pharmacy or state-run programs for the
disposal of expired medications instead of sending them down the sink
or the toilet bowl.
A pharmacist is the expert of choice to approach in
handling medication expiry and should be consulted if in doubt. As a
general rule, it is always best to safeguard your own health and that
of those around you by expeditiously and appropriately discarding all
expired medications.
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