Isosorbide Mononitrate

What is this medication for?

Isosorbide 5-Mononitrate Controlled Release (ISMN CR) belongs to a class of medications called Nitrates. Nitrates are used to prevent and treat the symptoms of angina. Angina is a condition caused by a lack of blood supply and oxygen to your heart. 

Symptoms of an angina attack may include:  

• Chest pain or chest tightness
• Shortness of breath
• Heavy sweating, or pain that spreads to your jaw, arm or back 

Nitrates work by relaxing blood vessels so that more blood and oxygen is supplied to the heart.

When you take this medication regularly on a long-term basis, it can help to reduce the number of angina attacks that occur.

Nitrates can also be used with other medications for the treatment of heart failure, a condition where the heart is weak and is unable to pump enough blood to the rest of the body.

How should I take or use this medication?

• Do not stop taking your medication without checking with your healthcare professional. Stopping your medication suddenly may cause angina attacks. Ask your doctor for recommendations on how to reduce the dose slowly before stopping completely.
• You may take this medication with or without food. The medication may be halved, but do not crush or chew the tablets.
• This medication is used to reduce the number of angina attacks that occur. They should not be used for immediate relief for chest pain.

What should I do if I forget to take or use this medication?

If you miss a dose, take the missed dose as soon as you remember. If it is almost time for your next dose, take only the usual dose. Do not double your dose or use extra medication to make up for the missed dose.

What precautions should I take when taking or using this medication?

Inform your healthcare professional if:

• You are allergic to this medication or any of the other ingredients of this medication
• You are pregnant, planning to become pregnant, or breastfeeding
• You are taking any other medications, including supplements, traditional medications and herbal remedies.
• You are planning to start or are taking Sildenafil, Tadalafil or Vardenafil. 

What are some common side effects of this medication? ​

Side effects may include:

• Dizziness, lightheadedness or faintness
  • This may occur especially when you get up quickly from lying or sitting down. Getting up slowly or changing posture slowly may help. Take a rest by sitting or lying down if you feel dizzy.
  • This is also more likely to happen if you drink alcohol, stand for a long period of time, exercise or when the weather is hot. Do limit the amount of alcohol you drink while you are on Nitrates. Do take extra care during exercise, when the weather is hot or if you need to stand for long periods of time.
• Temporary headache
  • This is a common side effect that will go away after taking the medication for a while. You may choose to take painkillers such as Paracetamol at the start of using Nitrates, to relieve the temporary headaches. Consult your healthcare professional if the headaches do not go away or become worse.
• Flushing or redness of the skin
• Fast heartbeat
• Nausea and Vomiting

What are some rare but serious side-effects that I need to seek medical advice immediately? 

It is very important that you are on regular follow-up with your doctor to monitor for any possible side-effects. Inform your healthcare professional if you have any of the following side-effects: 

• Very bad dizziness
• Fast or slow heartbeat
• Chest pain that is new or worse

The symptoms of a drug allergy include one or more of the following:

• Swollen face/eyes/lips/tongue
• Difficulty in breathing
• Itchy skin rashes over your whole body

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

What food or medication should I avoid when I take or use this medication?

Do not take Sildenafil (Viagra®), Tadalafil (Cialis®), Vardenafil (Levitra®) if you are taking this medication. When Sildenafil, Tadalafil or Vardenafil is taken with Nitrates, your blood pressure can lower greatly, resulting in dizziness, lightheadedness or fainting. 

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children. 

How do I throw away this medication safely? ​

Pack this medication into a black trash bag and seal it tightly before throwing into the rubbish chute or bin.