Patient leaflet - Securon SR
1. What Securon SR / Half Securon SR is and what is it used for
Securon SR and Half Securon SR contains the active substance verapamil hydrochloride.
Securon SR and Half Securon SR tablets belong to a group of medicines called calcium channel blockers. Calcium channel blockers change the amount of calcium getting into the muscle cells in your heart and blood vessels. This can change the strength and speed with which your heart beats. It also opens up the blood vessels so blood can be pumped around the body more easily. This helps more oxygen to get to your heart muscle and can lower your blood pressure.
Securon SR and Half Securon SR tablets are used to treat hypertension (high blood pressure) and to prevent angina (chest pain) attacks. The tablets may also be prescribed following a heart attack, to prevent another attack occuring.
2. What you need to know before you take Securon SR / Half Securon SR
Do not take Securon SR / Half Securon SR:
If you are allergic to verapamil hydrochloride or any of
the other ingredients of this medicine (listed in section 6).
- If you have had a heart attack with shock.
If you had a heart attack, particularly if a slow
heartbeat, low blood pressure or a type of heart failure called ‘left ventricular failure’.
If you have an abnormally slow or irregular heartbeat.
If you have second- or third-degree atrioventricular block or sino-atrial block. This is a disorder where parts of your heart may beat at the wrong time causing it not to pump blood around the body very well (unless a permanent pacemaker is in place).
If you have a problem where your heart beats very
slowly (bradycardia), unless you have been fitted with a pacemaker.
Do you have or have you ever suffered from heart
problems such as heart failure or the heart condition called Wolff-Parkinson-White syndrome?
If you are currently being treated with ivabradine (for
heart conditions)?
Warnings and Precautions
Talk to your doctor or pharmacist before using Securon SR and Half Securon SR
If you are pregnant or planning to become pregnant,
or you are breast feeding.
- If you have liver or kidney problems.
- If you have very low blood pressure.
If you are currently receiving lipid lowering agents
(e.g., simvastatin, atorvastatin or lovastatin)
If you have a condition where the nerve to muscle
transmission is affected e.g. myasthemia gravis, Lambert-Eaton syndrome, advanced Duchenne muscular dystrophy.
Take special care with Securon SR and Half Securon SR
Tell your surgeon or dentist that you are taking Securon SR or Half Securon SR if surgery is planned as it may affect the anaesthetic used.
Other medicines and Securon SR and Half Securon SR Tell your doctor or pharmacist if you are taking any medicines with or without a prescription or have recently taken any of the following medicines:
beta-blockers such as atenolol, propranolol and
metoprolol (used to treat high blood pressure and heart conditions)
alpha blockers such as prazosin and terazosin (used
to treat high blood pressure and heart conditions)
- diuretics (also called ‘water pills’)
medicines known as "statins" such as atorvastatin,
lovastatin, simvastatin (used to lower cholesterol levels)
quinidine, flecainide, disopyramide, digoxin and
digitoxin (used to treat high blood pressure or an abnormal heart beat (arrhythmia))
Dabigatran (used to thin blood) and direct oral
anticoagulants (DOACs)
- Ivabradine (used to treat certain heart diseases)
medicines used to treat depression, anxiety or
psychosis. These include the herbal product St John’s Wort or imipramine, buspirone and lithium
- medicines known as immunosuppressants such as cyclosporine, sirolimus, everolimus and tacrolimus (used to prevent organ transplant rejection)
- glyburide (glibenclamide), medicine used to treat certain types of diabetes
aspirin (a non-steroidal anti-inflammatory painkiller
(NSAID) used to relieve pain and reduce fever)
- almotriptan (used to treat migraine)
- midazolam ( used as a sedative or anaesthetic)
- theophylline (used to treat asthma)
- doxorubicin (an anti-cancer medicine)
- cimetidine (used to treat indigestion or stomach ulcers)
- rifampicin (used to treat tuberculosis and other types of infection)
carbamazepine, phenytoin or phenobarbital
(phenobarbitone), medicines used as anti-convulsants
- ritonavir (used to treat HIV)
- erythromycin, clarithromycin and telithromycin (used to treat types of infection)
- colchicine or sulfinpyrazone (used to treat gout)
- metformin. Verapamil may decrease the glucose-lowering effect of metformin.
- antihypertensives (used to treat hypertension)
- vasodilators (open (dilate) blood vessels) Securon SR and Half Securon SR with drink and alcohol
Do NOT drink grapefruit juice whilst taking Securon
SR and Half Securon SR as it can affect the absorption of this medicine. This does not occur with other fruit juices such as orange, apple or tomato juice.
- Securon SR and Half Securon SR will increase the time your body takes to get rid of alcohol. This means that you may not have to drink as much for your blood alcohol levels to be above the legal limit to drive. It will also take you longer to sober up.
Pregnancy, breast-feeding and fertility
If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor for advice before taking this medicine.
Sodium
Securon SR: This medicine contains 37.1 mg sodium (main component of cooking/table salt) in each tablet. This is equivalent to 1.9 % of the recommended maximum daily dietary intake of sodium for an adult.
BACK
Date: Time:
Description
Sign-offs
Securon SR, 120 mg, 240 mg, 28
Helvetica Neue 8 pt
8 pt
28-AUG-2026 10:30
N.A.
N.A.
Notes
V6 APR 2025
Half Securon SR: This medicine contains less than 1 mmol sodium (23 mg) per tablet, that is to say essentially ‘sodium-free’.
Driving and using machines
Do NOT drive, operate machinery or do anything that requires you to be alert, until you know how the tablets affect you.
Securon SR and Half Securon SR can make some people feel dizzy, especially when they first start to take the tablets.
3. How to take Securon SR / Half Securon SR
ALWAYS take this medicine exactly as your doctor has told you. Check with your doctor if you are not sure.
TAKE YOUR TABLETS with a glass of water. You should swallow the tablets without chewing or crushing them. The tablets should preferably be taken with or shortly after meals. The number of tablets that you will need to take will depend on what you are being treated for:
ADULTS:
Hypertension (high blood pressure)
The recommended dose is one Securon SR 240 mg tablet a day. If you have not taken Securon SR 240 mg before, your doctor may prescribe a lower dose such as a Half Securon SR 120 mg tablet each day. The maximum dose to treat high blood pressure is 480 mg each day. This is usually taken as one Securon 240 mg tablet in the morning and one in the evening, leaving a gap of about 12 hours between each dose.
Angina (chest pain)
The usual starting dose for angina is one Securon SR 240 mg tablet taken twice a day. You should take one tablet in the morning and one in the evening, with a gap of about 12 hours in between them. Your doctor may prescribe a lower dose according to your symptoms. Following a heart attack
The usual dose following a heart attack is 360 mg each day. This may be taken as one Securon SR 240 mg tablet in the morning and a Half Securon SR 120 mg tablet in the evening or as one Half Securon SR 120 mg tablet
taken three times a day. The doctor will usually wait at least a week after your heart attack before prescribing these tablets.
CHILDREN:
Securon SR and Half Securon SR are NOT recommended for children under 12 years of age.
Elderly
The dose will be the same as that for adults. If you have kidney or liver problem, your doctor may lower your dose.
If you take more Securon SR and Half Securon SR than you should
If you take more tablets than prescribed (an overdose) you should contact a doctor or go to the nearest hospital casualty department IMMEDIATELY taking your tablets with you.
If you forget to take Securon SR and Half Securon SR
If you forget to take your tablets take them as soon as you remember, unless it is almost time for your next dose. If it is, do not take the missed dose at all. Do not take double dose to make up for a forgotten tablet.
If you stop taking Securon SR and Half Securon SR
If you stop taking your tablets your condition may get worse. It is important that you keep taking these tablets until your doctor tells you to stop. Do NOT stop just because you feel better.
Other things to remember about Securon SR and Half Securon SR
Securon SR 240 mg tablets may be broken in half if
your doctor advises you to do so (e.g. if a lower dose has been prescribed).
The tablets should NOT be crushed, chewed or
sucked, as this will affect the modified-release formulation of the product.
If you have any further questions on the use of this medicine, ask your doctor or pharmacist.
4. Possible side effects
As with all medicines, Securon SR and Half Securon SR can cause side effects, although not everyone will suffer from them. If you experience any other unusual symptoms whilst taking your tablets, tell your doctor or pharmacist.
Tell your doctor IMMEDIATELY if you experience any of the following side effects:
Yellowing of the skin or eyes, a fever or tenderness
around the middle. These are signs that your liver may not be functioning as well as usual
Palpitations, chest pains for the first time or chest
pains becoming more frequent, swollen ankles, hot and painful hands or feet
- Swelling of the limbs
Unexpected wheezing, difficulty breathing, swelling
of the mouth, lips or tongue or severe skin rash The most common side effect is constipation. Other side effects include abnormal heart beat, flushing of the face or neck, headaches, feeling or being sick, abdominal pain or discomfort, dizziness, vertigo, tinnitus (ringing or buzzing in the ears), tiredness, tremor, movement disorders, muscle weakness, aches and pains in the joints and/or muscles, skin rash or itching, a tingling or prickling feeling on the skin, numbness and hair loss. Impotence may occur rarely.
Other side effects might occur if Securon SR or Half Securon SR are used for a long time. Tell your doctor if you develop swollen gums which start to spread over your teeth, or if your breasts swell (males) or start to produce milk (males and females). These effects are rare and are resolved upon stopping taking the tablets. Reporting of side effects
If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
By reporting side effects you can help provide more information on the safety of this medicine.
5. How to store Securon SR / Half Securon SR
Do not use this medicine after the expiry date which is stated on the carton after EXP. The expiry date refers to the last day of the month. Keep them in the original pack, at normal room temperature (do not store them above 25 °C). Keep this medicine out of the sight and reach of children.
Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.
6. Contents of the pack and other information
What Securon SR and Half Securon SR contains
The active substance is verapamil hydrochloride.
Each tablet contains either 120mg or 240mg of verapamil hydrochloride, in a sustained release (slow release) formulation.
- The other ingredients are sodium alginate, microcrystalline cellulose, povidone, purified water, talc, titanium dioxide (E171), hydroxypropyl methylcellulose, magnesium stearate, polyethylene glycol 400, polyethylene glycol 6000 and montan glycol wax. In addition, Securon SR (240mg) tablets contain L-green lake (quinoline yellow (E104) and indigo carmine (E132)).
What Securon SR and Half Securon SR look like and contents of the pack:
Securon SR tablets are pale green, oblong in shape and marked with two triangles on one side and scored. Each tablet contains 240 mg of verapamil hydrochloride. Half Securon SR tablets are white, round, biconvex and marked with the word ‘KNOLL’ on one side and ‘120 SR’ on the other. Each tablet contains 120 mg of verapamil hydrochloride.
The tablets are available in calendar packs of 28.
Marketing Authorisation Holder:
Viatris Products Limited,
Station Close, Potters Bar, EN6 1TL, United Kingdom.
Manufacturer:
FAMAR A.V.E.
ANTHOUSSA PLANT
Anthoussa Attiki
15349, Greece
This leaflet was last revised in September 2026.
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