Consumer Medicine Information
What is in this leaflet
This leaflet answers some common questions about Isoptin.
It does not contain all the available information.
It does not take the place of talking to your doctor or pharmacist.
All medicines have risks and benefits. Your doctor has weighed the risks of you taking
Isoptin against the benefits they expect it will have for you.
If you have any concerns about taking this medicine, talk to your doctor or pharmacist.
Keep this leaflet with the medicine.
You may need to read it again.
What Isoptin is used for
There are two types of Isoptin:
Isoptin tablets (available as 40 mg and 80 mg tablets)
Isoptin SR (available as 180 mg and 240 mg tablets)
The letters SR in the name Isoptin SR stand for "sustained release". This means the
medicine is released into the blood over an extended period of time, usually allowing
the medicine to be taken once a day.
Depending on your condition, your doctor will prescribe Isoptin or Isoptin SR.
In most parts of this leaflet, the name Isoptin is used to refer to both Isoptin tablets
and Isoptin SR tablets. Where there is information specific to the type of Isoptin,
the separate names are used.
Isoptin and Isoptin SR are used in the treatment of:
high blood pressure, also called hypertension
angina (chest pain)
Isoptin tablets are also used to treat irregular heartbeats, also called arrhythmias
Your doctor may have prescribed Isoptin for another reason. Ask your doctor if you
have any questions about why Isoptin has been prescribed for you.
Isoptin and Isoptin SR belong to a group of medicines called calcium channel blockers
or calcium antagonists. They work by opening up blood vessels, which lets more blood
and oxygen reach the heart and at the same time lowers high blood pressure. Isoptin
tablets also help to control fast or irregular heartbeats.
Isoptin does not change the amount of calcium in your blood or bones. Calcium in your
diet or in calcium supplements will not interfere with the way Isoptin works.
Isoptin SR is not recommended for use in children under the age of 18, as there have
been no studies of its effects in this age group.
Isoptin is available only with a doctor's prescription.
There is no evidence that Isoptin is addictive.
Before you take Isoptin
When you must not take it
Do not take Isoptin if you have an allergy to verapamil hydrochloride or any of the
ingredients listed at the end of this leaflet.
Some of the symptoms of an allergic reaction may include:
shortness of breath
wheezing or difficulty breathing
swelling of the face, lips, tongue or other parts of the body
rash, itching or hives on the skin
Do not take Isoptin if you:
have certain heart conditions (such as heart failure, a very slow heart rate, heart
conduction problems, some irregular heartbeats or disease of the heart muscle)
have low blood pressure, also called hypotension
are taking any of the following medications, or medications containing these ingredients:
Direct Oral Anticoagulants (DOACs) such as dabigatran (in certain situations)
Do not use Isoptin after the expiry date (EXP) printed on the pack.
If you take this medicine after the expiry date has passed, it may not work as well.
Do not use Isoptin if the packaging is torn or shows signs of tampering.
If you are not sure whether you should start taking Isoptin contact your doctor.
Before you start to take Isoptin:
Tell your doctor if you have allergies to:
any other medicines
any other substances, such as foods, dyes or preservatives.
Tell your doctor if you have or have ever had any medical conditions especially the
any other heart problem
blood vessel (circulatory) disease or a stroke
liver or kidney problems
muscle conditions such as Duchenne muscular dystrophy, myasthenia gravis, Lambert-Eaton
Tell your doctor if you are pregnant or plan to become pregnant.
Isoptin may affect your baby if you take it in pregnancy. Your doctor will discuss
the possible risks and benefits of taking Isoptin during pregnancy.
Tell your doctor if you are breastfeeding or plan to breastfeed.
Isoptin passes into breast milk. Your doctor will discuss the possible risks and benefits
of taking Isoptin when breastfeeding.
If you have not told your doctor about any of the above, tell them before you start
Taking other medicines
Several medicines can cause unwanted reactions if used with Isoptin.
Ask your doctor or pharmacist for advice before taking this medicine.
In particular tell your doctor if you are taking any of the following medicines:
Medicines to treat heart problems or high blood pressure:
Beta-blockers e.g. atenolol, propranolol, metoprolol, etc
Any other medicines used to control an irregular heartbeat e.g. quinidine, flecainide,
Any medicines used to control high blood pressure (especially prazosin or terazosin)
Medicines used to lower cholesterol:
Statins such as atorvastatin or simvastatin
Medicines used to treat or prevent blood clots (sometimes referred to as "blood thinners")
Direct Oral Anticoagulants (DOACs) such as dabigatran
Medicines used to treat or prevent gout:
Medicines used to treat psychological problems
Any medicines to treat depression, or psychosis. Such as imipramine, buspirone, midazolam
Medicines to treat epilepsy or seizures:
Phenytoin, carbamazepine, phenobarbital.
Medicines to treat or prevent organ transplant rejection:
Cyclosporin, everolimus, sirolimus, tacrolimus
Medicines used to treat infections or tuberculosis:
such as erythromycin, clarithromycin, telithromycin or rifampicin
Medicines used in the treatment of Human Immunodeficiency Virus (HIV):
such as ritonavir
Medicines used in surgical procedures:
General anaesthetics used for inducing sleep
Other medicines that may react with Isoptin:
theophylline, a medicine used to treat asthma
doxorubicin, a medicine used to treat certain cancers
cimetidine, a medicine commonly used to treat stomach ulcers and reflux
glibenclamide, a medicine used to treat diabetes
Avoid alcohol while using Isoptin. You may experience greater blood pressure lowering
effects than usual.
Avoid grapefruit juice, as this may increase the blood levels of verapamil.
These medicines may be affected by Isoptin, or may affect how well it works. You may
need different amounts of your medicine or you may need to take different medicines.
Your doctor will advise you.
This is not a complete list of medicines which may interfere with Isoptin.
Tell your doctor or pharmacist if you are taking or have recently taken any other
medicines or herbal remedies, including those obtained without a prescription from
a pharmacy, supermarket or health food shop.
How to take Isoptin
How much to take
Your doctor will tell you how many tablets you will need to take each day and when
to take them. This depends on your condition and whether or not you are taking any
Isoptin tablets are usually taken two or three times a day.
The usual dose of Isoptin SR is once daily or they may be taken twice daily.
Follow all directions given to you by your doctor carefully.
If you do not understand the instructions on the pharmacist's label fixed on the box,
ask your doctor or pharmacist for help.
How to take it
Swallow Isoptin with a glass of water.
Isoptin 40 mg and 80 mg tablets are to be swallowed whole. They are not meant to be
Isoptin SR tablets can be broken in half if your doctor has prescribed half a tablet.
Do not crush or chew Isoptin SR tablets.
When to take it
Take Isoptin SR with food.
Isoptin 40 mg and 80 mg tablets can be taken with or without food.
If you forget to take it
If it is almost time for your next dose, skip the dose you missed and take your next
dose when you are meant to. Otherwise, take it as soon as you remember, and then go
back to taking your medicine as you would normally.
Do not take a double dose to make up for the dose that you missed.
This may increase the chance of you getting an unwanted side effect.
If you miss more than one dose, or are not sure what to do, check with your doctor
How long to take it
Treatment with Isoptin is usually long term. Keep taking Isoptin for as long as your
If you take too much (overdose)
Immediately telephone your doctor or the Poisons Information Centre (telephone 13
11 26) for advice, or go to Accident and Emergency at your nearest hospital, if you
think that you or anyone else may have taken too much Isoptin. Do this even if there
are no signs of discomfort or poisoning.
You may need urgent medical attention.
If you take too much Isoptin, you may have a slow heartbeat, chest pain, feel very
faint or collapse; however, if you are taking Isoptin SR (sustained release) tablets
the medicine is released into the blood over an extended period of time, so you may
not notice these symptoms immediately.
While you are taking Isoptin
Things you must do
If you become pregnant while taking Isoptin, tell your doctor.
Tell all doctors, dentists and pharmacists who are treating you that you are taking
If you are being treated for angina, tell your doctor if you continue to have angina
attacks or if they become more frequent while you are using Isoptin.
If you are going to have surgery including dental surgery, tell your doctor or dentist
that you are taking Isoptin.
Visit your doctor regularly so that they can check on your progress.
Your doctor may ask you to have blood tests to check your liver from time to time.
Things you must not do
Do not take Isoptin with grapefruit or its juice.
Do not give Isoptin to anyone else, even if they have the same condition as you.
Do not take Isoptin to treat any other complaints unless your doctor tells you to.
Do not stop taking Isoptin, or lower the dosage without checking with your doctor.
Things to be careful of
Be careful getting up from a sitting position.
Dizziness, light-headedness or fainting may occur, especially when you get up quickly.
Getting up slowly may help.
Be careful driving or operating machinery until you know how Isoptin affects you.
As with other medicines, Isoptin may cause dizziness, light-headedness or tiredness
in some people. If this occurs, do not drive, operate machinery or do anything else
that could be dangerous if you are tired, dizzy or lightheaded.
If you drink alcohol while taking Isoptin, dizziness or light-headedness may be worse.
Tell your doctor or pharmacist as soon as possible if you do not feel well while you
are taking Isoptin.
Like all other medicines, Isoptin may have unwanted side effects in some people. Sometimes
they are serious, most of the time they are not. You may need medical treatment if
you get some of the side effects.
As with most medicines, if you are over 65 years of age you may have an increased
chance of getting side effects. Report any side effects to your doctor promptly.
Ask your doctor or pharmacist any questions you may have.
Tell your doctor if you notice any of the following more common side effects and they
feeling sick, upset stomach
Tell your doctor immediately or go to Accident and Emergency at the nearest hospital
if you notice any of the following:
chest pain, fainting, collapse
slow, fast, or irregular heart beat
shortness of breath (sometimes with tiredness, weakness and reduced ability to exercise),
which may occur together with swelling of the feet and legs due to fluid build up
fever, upper stomach pain, feeling generally unwell
severe blisters, skin rash, itching or flaking skin
Other side effects not listed above may occur in some patients. Ask your doctor or
pharmacist for more information about side effects, as they have a more complete list
of side effects. Inform your doctor promptly about these or any other symptoms. If
the condition persists or worsens, seek medical attention.
Do not be alarmed by this list of possible side effects.
You may not experience any of them.
Tell your doctor if you notice anything that is making you feel unwell.
After using Isoptin
Keep your tablets in the pack until it is time to take them.
If you take the tablets out of the pack they will not keep well.
Keep Isoptin tablets in a cool dry place where the temperature stays below 25°C.
Do not store Isoptin or any other medicine in the bathroom or near a sink.
Do not leave it in the car on hot days or on window sills.
Heat and dampness can destroy some medicines.
Keep your tablets where children cannot reach them.
Medicines should not be disposed of via wastewater or household waste.
If your doctor tells you to stop taking Isoptin, or the tablets have passed their
expiry date, ask your pharmacist what to do with any tablets left over.
What it looks like
Isoptin is available as:
Isoptin 40 mg: White, biconvex film coated tablets, embossed "40" on one side and
the Knoll triangle on the other side.
Isoptin 80 mg: White, biconvex film coated tablet embossed "Isoptin 80" on the front
and "Knoll" above the score on the back.
Each pack of Isoptin 40 mg and Isoptin 80 mg contains 100 tablets.
Isoptin SR is available as:
Isoptin 180 SR: Light pink capsule shaped, scored, film coated tablets with "SR 180"
on one side and "KNOLL" on the other side.
Isoptin 240 SR: Light green, capsule shaped, scored, film coated tablets with a double
Knoll triangle on one side.
Each pack of Isoptin 180 SR and Isoptin 240 SR contains 30 tablets.
Isoptin tablets and Isoptin SR tablets are gluten free.
The active ingredient in Isoptin is verapamil hydrochloride.
Isoptin tablets contain 40 mg or 80 mg of verapamil hydrochloride.
These tablets also contain:
calcium hydrogen phosphate dihydrate
colloidal anhydrous silica
sodium lauryl sulfate
Isoptin 180 SR tablets contain 180 mg of verapamil hydrochloride.
These tablets also contain:
iron oxide red
glycol/butylene glycol montanate
Isoptin 240 SR tablets contain 240 mg verapamil hydrochloride.
Isoptin 240 SR tablets also contain:
glycol/butylene glycol montanate
Isoptin tablets are supplied by:
Mylan Health Pty Ltd
Level 1, 30 The Bond
30-34 Hickson Road
Millers Point, NSW 2000
Phone: 1800 314 527
Australian registration numbers:
Isoptin 40 mg - AUST R 65502
Isoptin 80 mg - AUST R 65503
Isoptin 180 SR - AUST R 54032
Isoptin 240 SR - AUST R 12801
This leaflet was prepared on 4 February 2020.