What is Invokana used for?

• Type 2 diabetes (non-insulin dependent diabetes) in adults aged 18 years and over.
• Invokana tablets can be used on their own to improve blood sugar control in people whose blood sugar is not controlled by changes to their diet and exercise alone, and who can't take an antidiabetic medicine called metformin.
• Invokana tablets can also be used for people with type 2 diabetes whose blood sugar is not sufficiently controlled by other antidiabetic medicines. It can be added to treatment with medicines such as metformin, a sulphonylurea such as gliclazide or glibenclamide, or to treatment with insulin.

How does Invokana work?

• Invokana tablets contain the active ingredient canagliflozin, which is a type of medicine called an SGLT2 inhibitor.
• In type 2 diabetes the cells in the body become resistant to the action of insulin. Insulin is the main hormone responsible for controlling the level of sugar (glucose) in the blood. It makes cells in the body remove sugar from the blood. When the cells are resistant to insulin this makes blood sugar levels rise too high.
• Canagliflozin works in the kidneys, where it allows the body to excrete excess glucose from the blood into the urine.
• Normally, when the kidneys filter and clean the blood, glucose is filtered out of the blood at the same time. The glucose is then reabsorbed back into the blood by a mechanism called the sodium-glucose co-transporter 2 (SGLT2). The kidneys normally reabsorb glucose back into the blood even when the levels of glucose in the blood are too high, as in diabetes.
• Canagliflozin works by inhibiting the SGLT2 transporter. This allows excess glucose to be filtered out of the blood and excreted in the urine. This will reduce blood sugar levels.
• Canagliflozin has two other effects that may be of benefit for people with diabetes. Firstly, it may cause weight loss due to the loss of sugar from the body. Secondly, it causes a small increase in the amount of water being filtered out of the blood into the urine (diuresis). This may help to reduce blood pressure.

How do I take Invokana?

• Invokana tablets should be taken once a day, preferably before breakfast. You can take the tablet with or without food. The tablet should be swallowed whole with a drink of water.
• If you forget to take your tablet at your usual time, take it as soon as you remember. Take your next dose as usual the following day. Do not take a double dose (two tablets on the same day) to make up for a forgotten tablet.

What should I know before taking Invokana?

• It is important that you continue to follow the diet and exercise advice given to you by your doctor or nurse while you are taking Invokana. This medicine only helps to control your blood sugar levels and should not be used as a substitute for eating healthily and taking regular exercise. 

Invokana should be used with caution by

• Elderly people.
• People with kidney problems.
• People taking medicines for high blood pressure who have a history of low blood pressure or feeling dizzy.
• People with heart disease.
• People with a high percentage of red blood cells in their blood.
• People with a history of frequent urinary tract infections.
• People with a history of frequent genital infections such as thrush.

Who should not take Invokana?

• People with type 1 diabetes.
• People with diabetic ketoacidosis.
• People with moderate to severely decreased kidney function.
• People with severely decreased liver function.
• Women who are pregnant or breastfeeding.
• People who are allergic to any ingredients of the medicine, for example people with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption (Invokana tablets contain lactose).
• Invokana is not recommended for people taking loop diuretics such as furosemide.
• Invokana is not recommended for people with low fluid volume or salt levels in the body, eg due to diuretic therapy, diarrhoea or vomiting.
• Invokana is not recommended for children and adolescents under 18 years of age, because its safety and effectiveness have not been studied in this age group.

Can I take Invokana while pregnant or breastfeeding?

• The safety of canagliflozin for use during pregnancy has not been established and Invokana should not be used during pregnancy. Diabetes mellitus is usually controlled using insulin during pregnancy, because this provides a more stable control of blood sugar. If you get pregnant while taking Invokana, or are planning a pregnancy, you should seek medical advice from your doctor.
• It is not known if canagliflozin passes into breast milk. The manufacturer states that Invokana should not be used by breastfeeding mothers. Seek medical advice from your doctor.

What are the possible side effects of Invokana?

Very common

• Low blood sugar levels levels (when used with a sulphonylurea such as glibenclamide, or with insulin – see what should I know above).
• Vaginal thrush.

Common 

• Inflammation of the penis and/or foreskin (candidal balanitis) due to thrush infection.
• Constipation.
• Feeling thirsty.
• Feeling sick.
• Increased production of urine (polyuria).
• Needing to pass urine at night (nocturia).
• Urinary tract infections.
• Increased percentage of red blood cells in the blood (increased haematocrit).
• Changes in the levels of cholesterol and other fats in the blood.

Uncommon

• Dehydration. Consult a doctor straight away if you experience symptoms of this, such as excessive thirst, a very dry or sticky mouth, dizziness, sleepiness, a fast heartbeat, or passing little or no urine. 
• Low blood pressure and dizziness, particularly when standing up from sitting or lying down. See what should I know above.
• Fainting.
• Skin reactions such as rash, itching, hives.
• Increased creatinine and urea (markers of kidney function) in the blood.
• Increased level of potassium or phosphate in the blood.
• Bone fractures.

If you want any more information about the possible side effects of Invokana you should talk to your doctor or pharmacist, or read the leaflet that comes with the medicine.

Can I take Invokana with other medicines?

This medicine may enhance the effect of diuretic medicines such as furosemide or bendroflumethiazide, which help to remove water from the body. Your doctor may change the dose of canagliflozin or the diuretic medicine to make sure that you do not lose too much fluid. Canagliflozin is not recommended for people who are taking loop diuretics such as furosemide or bumetanide.

The following medicines may reduce the amount of canagliflozin in your blood. As this could make the canagliflozin less effective, your doctor may prescribe you a higher dose of canagliflozin if you are taking one of these:

• carbamazepine
• barbiturates such as phenobarbital, amobarbital
• efavirenz
• phenytoin
• rifampicin
• ritonavir
• the herbal remedy St John's wort (Hypericum perforatum).

Taking this medicine in combination with digoxin can increase the amount of digoxin in the blood. Your doctor may need to monitor your digoxin levels and adjust your dose if necessary.

If you have been prescribed a bile acid sequestrant such as cholestyramine or colestipol as well as Invokana you should take your Invokana at least one hour before, or at least four hours after taking the cholestyramine or colestipol. This is because these medicines reduce the absorption of canagliflozin and make it less effective if they are taken at the same time.

Medicines that increase blood sugar levels as a side effect may make Invokana less effective at controlling blood sugar. Medicines that can increase blood sugar levels include the following:

• antipsychotic medicines, such as chlorpromazine, olanzapine, risperidone
• beta-2-agonists, such as salbutamol, salmeterol
• corticosteroids, such as prednisolone
• glucosamine
• oestrogens and progestogens, such as those found in oral contraceptives or HRT
• thiazide diuretics, such as bendroflumethiazide.

References:

https://www.medicines.org.uk/emc/medicine/28400#gref

https://www.netdoctor.co.uk/medicines/diabetic/a8900/invokana-canagliflozin/

https://www.invokana.com

https://www.medicines.ie/medicines/invokana-100-mg-and-300-mg-film-coated-tablets-32512/patient-info

https://www.webmd.com/drugs/2/drug-163874/invokana-oral/details

https://www.diabetes.co.uk/diabetes-medication/invokana-canagliflozin.html

https://www.rxlist.com/invokana-side-effects-drug-center.htm

https://www.drugs.com/invokana.html