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Dangerous Drug Combinations
What are dangerous drug
combinations?
Dangerous drug combinations may include
mixing of any of the following:
• alcohol
• tobacco
• illegal drugs
• prescription medications
• non-prescription medications
• natural health products
• dietary supplements
Some interactions are minor, but others can
be dangerous and possibly life-threatening.
How do drug combinations
work?
When drugs are combined, there are three
possible effects:
1) They act independently of one
another. For example, alcohol does
not seem to interfere with vitamins
or oral contraceptives (birth control
pills), or vice versa.
2) They can increase each other’s
effects. This could happen because
they affect the brain in the same
way or because one drug increases
the concentration of the other in
the body. For instance, alcohol and
antihistamines are both central
nervous system depressants.
This means they slow the central
nervous system down. Mixing
them can make both the wanted
effects of the drugs (e.g., decreasing
self-consciousness) as well as
the side-effects (e.g., drowsiness)
stronger. Some drugs become more
dangerous when they are mixed.
This is because their effects are
compounded, increasing the way
they affect the body and the risk of
side effects or overdose.
3) They can decrease each other’s
intended effects. This could occur
when one drug “blocks” or prevents
another drug from working. It
could also happen when two drugs
have opposite effects on the brain
(e.g., drowsiness caused by alcohol
versus alertness caused by caffeine).
When prescription medication is
mixed with other drugs or alcohol,
the medication may not work as it
should.
It is…common for people to
use an unsafe combination of
drugs without realizing what
they are doing.
Primer Fact Sheets | 2008 | Dangerous Drug Combinations | www.heretohelp.bc.ca
How common is it for people
to use dangerous drug
combinations?
People sometimes mix drugs on purpose
to make the effects stronger, or to offset
unwanted side-effects. Combining heroin
and cocaine in a “speedball” is a common
example of this.
It is also common for people to use an unsafe
combination of drugs without realizing what
they are doing. This is widespread among
older people who are more likely to be on
prescription medications. For example,
someone may take sleeping pills after
drinking alcohol without understanding that
using these drugs together is dangerous.
Recent studies show that interactions
between alcohol and medication may be a
factor for a significant number of the people
who are admitted into emergency at hospitals
in Canada.
What are the risks of dangerous
drug combinations?
Drugs can act together in unexpected ways.
It is important to remember this whenever
you are taking more than one drug at a
time. Awareness helps to lower the risk
of dangerous drug interactions, but the
ways drugs interact with each other are
unpredictable. Sometimes negative effects
do not show until a drug has been used for a
long time. This applies to therapeutic drugs
(like medications), as well as to drugs taken
for non-medical purposes.
There is always some danger associated with
mixing drugs, but the actual risks involved
depend on the kind of drugs being combined
and the amounts being used. Alcohol is
perhaps most often mixed with other drugs.
It is also among the most dangerous when
combined with other substances.
Possible results of some drug combinations
with alcohol are:
Combination
Possible Results
alcohol + depressants (benzodiazepines such
as Valium, Xanax and Ativan)
alcohol + anti-depressants (e.g., Prozac,
Elavil, Nardil)
alcohol + antibiotics (especially
Metronidazole, Tinidazole, furazolidone
(Furoxone), griseofulvin (Grisactin),
Erythromycin, Linezolid, Co-trimoxazole, and
Antimalarial Quinacrine (Atabrine))
alcohol + prescription medications
Slow down of central nervous system, loss of coordination, coma, high
risk of overdose and death.
Increased central nervous system depression, massive blood pressure
increases which can result in brain hemorrhage and death.
In general, alcohol may cause antibiotics to be sent out to the body
more quickly or take longer to break down in the bloodstream. With the
specific drugs listed, combining alcohol may cause headaches, irregular
heart rate, low blood pressure, breathlessness, nausea, and vomiting.
alcohol + opiates (heroin, codeine)
alcohol + tobacco
alcohol + cannabis
alcohol + stimulants
Cancelled benefits of antibiotics and other medications. Side effects
such as cramps, vomiting and headaches (even aspirin can increase
the absorption of alcohol and irritates stomach lining. This can lead
to gastrointestinal pain and bleeding. Alcohol mixed with anti-alcohol
medication can cause headache, nausea, convulsions, coma and death).
Serious central nervous system depression, which can lead to respiratory
arrest (when a person stops breathing) and death.
More than doubles the effect of tobacco, and increases the absorption of
toxins.
More than doubles the effect of cannabis, and increases the absorption
of toxins.
Can mask depressant effects of alcohol. Can increase blood pressure,
tension and jitters. When alcohol and cocaine are mixed, the body
converts their broken-down products into cocaethylene, a chemical more
deadly than cocaine, which increases the risk of overdose.
PrimerFact
2007
| Post| 2008
Partum
Depression
Factsheet
| www.heretohelp.bc.ca
Primer
Sheets
| Dangerous
Drug
Combinations
| www.heretohelp.bc.ca
Some other risky combinations include:
• Fentanyl and heroin or cocaine:
recently flagged as a dangerous drug
combination being used on the streets.
Fentanyl is 50 to 100 times stronger
than morphine. When mixed with
heroin or cocaine it can cause irregular
heartbeat, the inability to breathe, and
death.
• Warfarin (a blood thinner sold as
Coumadin) and Aspirin: can increase
the risk of bleeding. The risk is even
higher when taken with garlic pills.
• Lisinopril (a blood pressure drug) and
potassium: can cause abnormal heart
rhythms. Potassium is often prescribed
to rebuild low levels of this mineral
caused by some blood pressure drugs.
• Prescription cholesterol drugs called
statins and over-the-counter niacin
(a type of vitamin B that also lowers
cholesterol): increases the risk of
muscle damage.
Care should be taken when illicit drugs are
combined with prescription medications as
these combinations can be dangerous. The
most common toxic effects are:
• central nervous system depression,
which can range from drowsiness (at its
mildest) to coma (at its most severe)
• respiratory depression, which can lead
to a person not breathing
• cardiac effects, such as changes in
heart rhythm that can lead to the heart
stopping
• decreased seizure threshold, meaning
that the brain can have a seizure more
easily
• psychiatric effects, such as psychosis
Fast facts about dangerous
drug combinations:
• Government reports rank alcoholdrug combinations as the leading
cause of drug-related deaths in
the United States, and have for
decades.
• A majority of all the poisonings
and overdoses that take place
every year are accidents.
How to avoid dangerous drug
combinations
The only way to completely protect yourself is
to avoid mixing drugs altogether. When that
is not possible, make sure you know exactly
what you are taking, why, and how those
drugs could interact with one another.
Many medications can be taken together
safely. Talk to your doctor or pharmacist
before you start taking anything. Make
sure they are aware of the medications
you are already on. They will be able to
tell you the possible effects of combining
specific prescription medications, painkillers
or supplements. It is best not to rely on
information found on the Internet as it can be
unclear or wrong.
People using illegal drugs should also talk
to their doctor or pharmacist before taking
prescription medications. Illegal drugs can
dangerously change the effects of certain
medications.
SheetsDepression
| 2008 | Dangerous
Drug Combinations
| www.heretohelp.bc.ca
Primer 2007 | Primer
Post Fact
Partum
Factsheet
| www.heretohelp.bc.ca
www.heretohelp.bc.ca
DO:
• Know what you are taking, why and
what the possible side effects may be
• Check with your doctor or pharmacist
before mixing drugs or medications of
any kind (including dietary supplements
and natural health products)
DON’T:
• Swap prescription medications with
friends or family members
• Increase dosages of medications
or pain killers to try to increase the
effectiveness
What to do if you or someone
you know needs help
For information on treatment options and
resources throughout British Columbia, call
Alcohol and Drug Information Referral
Service
1–800–663–1441 (throughout BC)
604–660–9382 (in Greater Vancouver)
For information on ways to help yourself
with a substance use problem, see the “Tips”
section of the Here to Help website:
www.heretohelp.bc.ca. The website also
features detailed information on substances
and mental health disorders.
You can also find information on a wide
variety of substance use issues on the Centre
for Addictions Research of BC website:
www.carbc.ca.
The BC Partners are a group of nonprofit agencies working together to help
individuals and families manage mental health and substance use problems,
with the help of good quality information. We represent Anxiety Disorders
Association of BC, BC Schizophrenia Society, Canadian Mental Health
Association’s BC Division, Centre for Addiction Research of BC, FORCE
Society for Kid’s Mental Health, Jessie’s Hope Society, and Mood Disorders
Association of BC. The BC Partners are funded by BC Mental Health and
Addiction Services, an agency of the Provincial Health Services Authority.
Produced by the Centre for Addictions Research of BC.