Taking Over-the-Counter (OTC)
Medicines Safely
his chart contains information about some of the more frequent drug interactions that may occur when
you are taking over-the-counter (OTC) medicines with prescription medicines. In order to take all of
your medicines safely and effectively, always check the active ingredients of your OTC medicines, located
on the label. Many OTC medicines contain more than one active ingredient, any of which may interact with
your prescription or other OTC medicines that you may be taking.
T
The information is provided for educational purposes only and should not replace the advice of your doctor.
If you have any questions about these medicines, or before making changes to your drug regimen talk to your
doctor or pharmacist.
Acid reducers for the temporary relief of indigestion, inflammation of the esophagus, acid
reflux or ulcers
OTC Medicine
cimetidine
(Tagamet HB®)
continued on next page
Interacts with
alprazolam,
amitriptyline,
imipramine
nortriptyline,
paroxetine,
Risperdal®,
sertraline
Effects of Interactions
Safety tips/ possible side effects
Tagamet HB may increase the effects of OTC medicine:
®
of these medicines and may cause
unwanted side effects. Check with
your doctor or pharmacist before
taking together to review potential
side effects of these medicines.
cyclosporine
metformin, glipizide
warfarin
Acid reducers
Tagamet HB® may lead to confusion
in older adults and is not usually
recommended as the acid reducer
of choice.
Tagamet HB® may interact with many
different medicines. Always check with
your doctor or pharmacist before taking
with your other medicines.
Flomax®
dofetilide (Tikosyn®)
Cranberry products may reduce the
effectiveness of acid reducers.
The use of these medicines together is
not recommended and is usually
avoided since it may have a harmful
effect on the heart.
Acid reducers
Acid reducers for the temporary relief of indigestion, inflammation of the esophagus, acid
reflux or ulcers (continued)
OTC Medicine
Interacts with
Effects of Interactions
cimetidine
(Tagamet HB®)
alcohol
Tagamet HB may increase the
negative effects of alcohol.
from previous page
carvedilol,
diltiazem,
flecainide,
labetalol,
metoprolol,
pentoxyphylline,
propranolol,
Tagamet HB® may increase the effects
of these medicines and may cause
unwanted side effects. Check with
your doctor or pharmacist before
taking together to review potential
side effects of these medicines.
Demerol®,
morphine
Dilantin®
theophylline
Zomig®
®
Safety tips/ possible side effects
of OTC medicine:
Cranberry products may reduce the
effectiveness of acid reducers.
Tagamet HB® may lead to confusion in
older adults and is not usually
recommended as the acid reducer
of choice.
Tagamet HB® may interact with many
different medicines. Always check with
your doctor or pharmacist before taking
with your other medicines.
Acid reducers for the temporary relief of indigestion, inflammation of the esophagus, acid
reflux or ulcers (continued)
OTC Medicine
Interacts with
famotidine (Pepcid AC )
®
cyclosporine
Sporanox®
Acid reducers
Effects of Interactions
When used together the effect of
the cyclosporine may be decreased.
Check with your doctor before taking
these medicines together because
additional monitoring may be
necessary.
Famotidine may decrease the effects
of Sporanox®. If taken together, it is
recommended to take Sporanox®
with a cola beverage.
Safety tips/ possible side effects
of OTC medicine:
Cranberry products may reduce the
effectiveness of acid reducers.
If you have kidney disease consult your
doctor before taking Pepcid AC®. Special
dosing may be necessary.
Acid reducers
Acid reducers for the temporary relief of indigestion, inflammation of the esophagus, acid
reflux or ulcers (continued)
OTC Medicine
omeprazole
(Prilosec OTC®)
Interacts with
carbamazepine
diazepam
digoxin
methotrexate
Pletal®
Effects of Interactions
Safety tips/ possible side effects
Prilosec OTC® may increase the effects of OTC medicine:
of these medicines and may cause
unwanted side effects. Check with
your doctor or pharmacist before
taking together to review potential
side effects of these medicines.
warfarin
ginkgo biloba,
St John’s Wort
These herbal supplements may
decrease the effectiveness of Prilosec
OTC®. Check with your doctor before
taking together.
Plavix®
Prilosec OTC® may decrease the effect
of Plavix® and may increase the risk of
blood clots. Check with your doctor
before taking Plavix® and Prilosec
OTC® together.
Cranberry products may reduce the
effectiveness of acid reducers.
Prilosec OTC® does not work immediately
to relieve symptoms. It may take a few
days for the effects to be felt.
Acid reducers for the temporary relief of indigestion, inflammation of the esophagus, acid
reflux or ulcers (continued)
OTC Medicine
ranitidine (Zantac 75 )
®
Interacts with
glipizide
triazolam, Risperdal®
warfarin
Sporanox®
Acid reducers
Effects of Interactions
Safety tips/ possible side effects
Zantac 75 may increase the effects of of OTC medicine:
®
these medicines when used together
and may increase unwanted side
effects. Check with your doctor or
pharmacist before taking together to
review potential side effects of these
medicines.
Zantac 75® may decrease the effects
of Sporanox® when used together. If
taken together, it is recommended to
take Sporanox® with a cola beverage.
Cranberry products may reduce the
effectiveness of acid reducers.
If you have kidney disease consult your
doctor before taking Zantac 75®. Special
dosing may be necessary.
Antacids
Antacids for the temporary relief of indigestion, heartburn and/or sour stomach
OTC Medicine
aluminum/magnesium
(Gaviscon®)
calcium carbonate
(Tums®)
magnesium hydroxide
(Milk of Magnesia®)
continued on next page
Interacts with
Allegra®
allopurinol
captopril
Cellcept®
Crestor®
digoxin
K-Phos®
Cipro®, Levaquin®,
tetracyclines
Effects of Interactions
Safety tips/ possible side
Antacids may decrease the effects of effects of OTC medicine:
these medicines if taken together. It
is best to speak with your doctor or
pharmacist to check when you
should take these medicines.
Check with your doctor or pharmacist
about how to take your antacids with
different medicines. Antacids may
decrease the effects of many different
medicines and may need to be taken at
different times of the day to avoid a
decreased effect.
Use caution when taking antacids
containing calcium if you have or have
had kidney disease or kidney stones.
Neurontin®
Antacids containing aluminum should not
be taken if you have bone problems (such
as osteoporosis) and should be avoided if
you have Alzheimer’s disease.
Prevacid®
Antacids containing:
propranolol
• Calcium carbonate may cause
constipation
levothyroxine,
Levoxyl®, Synthroid®
Sporanox®
ticlopidine
• Magnesium may cause diarrhea
Antacids for the temporary relief of indigestion, heartburn and/or sour stomach (continued)
OTC Medicine
aluminum/magnesium
(Gaviscon®)
calcium carbonate
(Tums®)
Interacts with
Prograf®
Effects of Interactions
Antacids may increase the effects of
Prograf®. Check with your doctor
before taking these medicines
together because additional
monitoring may be necessary.
magnesium hydroxide
(Milk of Magnesia®)
from previous page
Safety tips/ possible side
effects of OTC medicine:
Check with your doctor or pharmacist
about how to take your antacids with
different medicines. Antacids may
decrease the effects of many different
medicines and may need to be taken at
different times of the day to avoid a
decreased effect.
Use caution when taking antacids
containing calcium if you have or have
had kidney disease or kidney stones.
Antacids containing aluminum should not
be taken if you have bone problems (such
as osteoporosis) and should be avoided if
you have Alzheimer’s disease.
Antacids containing:
• Calcium carbonate may cause
constipation
• Magnesium may cause diarrhea
Antacids
Antihistamines
Antihistamines
for allergies or the common cold. Temporarily relieves symptoms such as:
runny nose, itchy eyes, itchy throat and/or sneezing
OTC Medicine
diphenhydramine
(Benadryl®)
Interacts with
metoprolol
Effects of Interactions
The use of these medicines
together may result in slowed heart
rate, low blood pressure and fatigue.
It is best to speak with your doctor
about whether it is safe to take
these medicines together.
Safety tips/ possible side
effects of OTC medicine:
Ask your doctor before using antihistamines if you are taking medicines such as
monoamine oxidase inhibitors (MAOI),
antidepressants or anti-psychotics.
Diphenhydramine may cause drowsiness,
dry mouth and/or dry eyes.
Aspirin containing products for upset stomach
OTC Medicine
bismuth subsalicylate
(Pepto-Bismol®)
Interacts with
doxycycline,
minocycline,
tetracycline
Effects of Interactions
Pepto-Bismol® may decrease the
effects of these antibiotics. If taken
together, it is recommended to take
the antibiotic 2-3 hours before the
Pepto-Bismol®.
Safety tips/ possible side effects
of OTC medicine:
Check with your doctor before using
Pepto-Bismol® if you have an allergy to
aspirin or nonsteroidal anti-inflammatory
drugs (NSAIDs) such as naproxen or
ibuprofen. It contains a form of aspirin
and may also cause an allergic reaction.
May cause a temporary darkening of stool
and/or tongue.
warfarin
Taking Pepto-Bismol® with warfarin
may increase the risk of bleeding.
Check with your doctor before using
these medicines together. Call your
doctor immediately if you have any
unexplained bruising, bleeding gums,
red or dark brown urine or black
stools.
Aspirin
Aspirin
Aspirin for heart attack prevention
OTC Medicine
Buffered aspirin
(Bufferin®)
Enteric coated aspirin
(Ecotrin®)
continued on next page
Interacts with
Celebrex®
diltiazem
diclofenac
Orudis®
citalopram,
Cymbalta®, Lexapro®
Effexor®, fluoxetine,
paroxetine, Pristiq®,
sertraline
gingko biloba
verapamil
Effects of Interactions
Taking aspirin with these medicines
may increase the risk of developing a To avoid upset stomach, take with food or
milk.
stomach bleed.
Enteric coated aspirin which has a special
coating) may reduce the risk of a stomach
ulcer or bleed.
Taking aspirin with these medicines
Do not crush, chew or break enteric
may increase the risk of bleeding.
coated tablets.
Call your doctor immediately if you
have signs of bleeding such as dark
Check with your doctor before starting
stools, bloody vomit, nose bleeds or aspirin therapy if you have an allergy to
unexplained bruising.
aspirin or nonsteroidal anti-inflammatory
drugs (NSAIDs) such as naproxen or
ibuprofen.
warfarin
ibuprofen
Safety tips/ possible side effects
of OTC medicine:
Taking ibuprofen with aspirin may
decrease the heart protection effects
of the aspirin. If you take them
together, it is recommended to take
aspirin 30 minutes before taking
ibuprofen or 8 hours after taking
ibuprofen.
Call your doctor immediately if you
experience:
• blood in your stool, vomit, or urine
• severe stomach pains
• trouble breathing
Aspirin for heart attack prevention (continued)
OTC Medicine
Buffered aspirin
(Bufferin®)
Enteric coated aspirin
(Ecotrin®)
Interacts with
dexamethasone,
methylprednisolone,
prednisone
Effects of Interactions
Taking aspirin with steroids may
increase the risk of stomach
upset, bleeding or ulcers.
Safety tips/ possible side effects
of OTC medicine:
To avoid an upset stomach, take with food
or milk.
Enteric coated aspirin (which has a special
coating) may reduce the risk of a stomach
ulcer or bleed.
from previous page
ranitidine
Taking ranitidine with aspirin may
decrease the heart protection effects
of the aspirin. Check with your
doctor before taking together.
Do not crush, chew or break enteric
coated tablets.
Check with your doctor before starting
aspirin therapy if you have an allergy to
aspirin or nonsteroidal anti-inflammatory
drugs (NSAIDs) such as naproxen or
ibuprofen.
Call your doctor immediately if you
experience:
• blood in your stool, vomit, or urine
• severe stomach pains
• trouble breathing
Aspirin
Cough Suppressant
Cough suppressant for a dry, non-productive cough
OTC Medicine
dextromethorphan
(Delsym®)
Interacts with
fluoxetine,
paroxetine
Zyvox®
Effects of Interactions
The use of these medicines together
may increase the risk of side effects
such as blurred vision, nausea,
vomiting, high blood pressure, fever,
nervousness, confusion and tremors.
Check with your doctor before
taking together. If taken together,
monitor for side effects.
Grapefruit products
Taking grapefruit products while
taking dextromethorphan may
increase the risk of side effects
such as dizziness, drowsiness and
fatigue. It is not recommended
to consume grapefruit with
dextromethorphan.
Haldol®
The use of these medicines together
may increase the risk of side effects
such as confusion, trouble breathing,
nervousness and tremors. Check with
your doctor before taking together. If
taken together, monitor for side
effects.
Safety tips/ possible side effects
of OTC medicine:
Dextromethorphan may cause dizziness,
drowsiness or weakness.
The use of a monoamine oxidase inhibitor
(MAOI) (such as Nardil®, Parnate® or
selegiline) with dextromethorphan may
cause severe confusion, headache, fever
or high blood pressure. The use of MAOIs
and dextromethorphan should be avoided.
Do not use dextromethorphan within
14 days of taking MAOI.
Iron supplementation for iron deficiency
OTC Medicine
ferrous fumarate
(Ferro-sequels®)
ferrous gluconate
(Fergon®)
Interacts with
Effects of Interactions
dairy products
Dairy products may decrease the
effect of iron. It is recommended
not to take iron with dairy products.
carbidopa/levodopa
Iron may decrease the effectiveness
of carbidopa/levodopa. Check with
your doctor before taking together.
Higher doses of carbidopa/levodopa
may be needed for the best effect.
ferrous sulfate
(Feosol®)
doxycycline,
Levaquin®,
minocycline,
tetracycline
Levoxyl®
Prilosec®
Safety tips/ possible side effects
of OTC medicine:
For best effect take iron on an empty
stomach, 1 hour before or 2 hours after a
meal. If stomach upset occurs, iron may
be taken with food.
Take iron with a full glass of water.
Iron may darken the color of your stool.
Always check with your doctor before
starting an iron supplement to be sure you
The effects of these medicines may be are taking the appropriate dose.
decreased if taken with iron. Check
with your doctor or pharmacist to find
out when you should take these
medicines.
Prilosec® may decrease the effect of
iron. Check with your doctor before
taking together. Your doctor may
have to monitor your iron levels more
closely and increase your iron dose for
the best effect.
Iron
Laxatives
Laxatives for relief of occasional constipation
OTC Medicine
senna (Senokot®,
ex-lax®)
Interacts with
digoxin
Effects of Interactions
The use of these medicines together
may increase the risk of digoxin side
effects such as nausea, vomiting,
vision changes (such as halos around
lights) and confusion. Check with
your doctor before taking together. If
used together you should monitor for
side effects and report side effects to
your doctor.
Safety tips/ possible side effects
of OTC medicine:
Ask your doctor before using laxatives if
you have:
• abdominal pain
• appendicitis
• bowel obstruction
• Crohn’s disease
• nausea, vomiting
These medicines are intended for short
term relief of constipation and should not
be used for more than 7 days without
consulting with your doctor.
Prolonged use may lead to laxative
dependency.
Excessive use may alter your sodium and
potassium levels.
Nasal decongestants for stuffy head and stuffy nose
OTC Medicine
phenylephrine
(Sudafed PE®)
Interacts with
amitriptyline,
desipramine,
doxepin,
imipramine,
nortriptyline
propranolol
pseudoephedrine
(Sudafed®)
Zyvox
®
Effects of Interactions
When these medicines are taken
together there may be an increased
risk of developing high blood
pressure, rapid heart rate and
irregular heartbeat. It is recommended
to avoid taking phenylephrine if you
are taking these antidepressants.
The use of these medicines together
may increase the risk of high blood
pressure, so check with your doctor
before using them together. If taken
together, monitor your blood pressure.
The use of these medicines together
may cause an increase in blood
pressure in people who don’t
normally have high blood pressure.
It is recommended to avoid using
pseudoephedrine and Zyvox® together.
Safety tips/ possible side effects
of OTC medicine:
Nasal decongestants may temporarily
cause sleeplessness, nervousness and restlessness. To prevent having trouble falling
asleep, take your last dose at least a few
hours before bedtime.
Nasal decongestants may also raise blood
sugar and blood pressure or cause heart
palpitations. If you are currently taking
medicine for high blood pressure or high
blood sugar, check with your doctor before
taking nasal decongestants.
The use of nasal decongestants with
a monoamine oxidase inhibitor (MAOI)
such as Nardil®, Parnate® or selegiline
is not recommended. Avoid using together
with, or within 14 days of, taking MAOI.
Nasal Decongestants
Non-aspirin pain relievers
Non-aspirin pain relievers for fever, headache and/or generalized pain
OTC Medicine
acetaminophen
(Tylenol®)
Interacts with
carbamazepine,
Dilantin®
Effects of Interactions
May increase the risk of liver damage
if these medicines are taken with
higher doses of acetaminophen
(greater than 1,300 mg per day) for
more than a few days.
Safety tips/ possible side effects
of OTC medicine:
Check with your doctor before using
acetaminophen or acetaminophen
containing products if you have liver
problems.
Do not exceed the recommended
acetaminophen maximum dose of 4,000
mg per day. Higher doses may increase the
risk of liver damage.
warfarin
Although acetaminophen is the
recommended pain reliever while on
warfarin, it is best to limit intake of
large amounts and prolonged use.
Taking warfarin with more than
2,000 mg of acetaminophen per day
for more than a few days may
increase the risk of bleeding.
Additional PT/INR blood tests may be
required.
Check with your doctor before using
acetaminophen if you have more than
3 alcoholic drinks per day on a regular
basis. Alcohol may increase your risk
of liver damage when taken with
acetaminophen.
Nonsteroidal anti-inflammatory drugs (NSAIDs) for headache, arthritis
and/or generalized pain
OTC Medicine
ibuprofen (Advil®)
naproxen (Aleve )
®
continued on next page
Interacts with
Effects of Interactions
Blood pressure
medicines or
diuretics (fluid pills)
When NSAIDs are used together with
these medicines, there may be a
decrease in the effects of blood pressure
medicines, and an increase in blood
pressure. If medicines are used together,
monitor your blood pressure closely.
cyclosporine
NSAIDs may increase the side effects
and blood levels of these medicines.
Close monitoring of side effects and
blood levels may be required.
Safety tips/ possible side
effects of OTC medicine:
Check with your doctor before using
NSAIDs if you have:
• anemia
• asthma
• aspirin allergy
• bleeding disorders
citalopram, fluoxetine, When NSAIDs are taken together with • heart failure
paroxetine,
these medicines there may be an
• high blood pressure
sertraline
increased risk of bleeding. Call your
• fluid retention
doctor immediately if you have signs of • kidney disease
ginkgo biloba
bleeding such as dark stools, bloody
• recent coronary artery bypass graft
Lovenox®, Plavix®,
vomit, nose bleeds or unexplained
surgery (CABG)
warfarin
bruising.
• ulcers or stomach bleeding
Dilantin®
lithium
tacrolimus
glyburide,
glipizide
It is best if you take NSAIDs with food.
Tell your doctor if you experience the
following symptoms while taking
NSAIDs:
• bloody vomit or dark stools
NSAIDs may increase the effects of these • stomach pain
medicines and may cause hypoglycemia • swelling of the feet
(low blood sugar). Close monitoring of
blood sugar is recommended.
NSAIDs
NSAIDs
Nonsteroidal anti-inflammatory drugs (NSAIDs) for headache, arthritis
and/or generalized pain (continued)
OTC Medicine
ibuprofen (Advil®)
naproxen (Aleve )
®
from previous page
Interacts with
ketorolac
Effects of Interactions
The use of NSAIDs with keterolac is
not recommended because of the
increased risk of stomach bleed or
ulcers. Talk to your doctor about use
of a different pain medicine.
Safety tips/ possible side effects
of OTC medicine:
Check with your doctor before using
NSAIDs if you have:
• anemia
• asthma
• aspirin allergy
• bleeding disorders
• heart failure
• high blood pressure
• fluid retention
• kidney disease
• recent coronary artery bypass graft
surgery (CABG)
• ulcers or stomach bleeding
It is best if you take NSAIDs with food.
Tell your doctor if you experience the
following symptoms while taking NSAIDs:
• bloody vomit or dark stools
• stomach pain
• swelling of the feet
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