Istin

What is Istin?

Istin is a type of medication called a calcium channel blocker used to treat high blood pressure. It helps to keep your blood pressure under control in the long term and prevents a heart attack or stroke from occurring in the future. Also known as amlodipine, it can be used to help treat angina and the chest pain associated with it too.

How does Istin work?

Istin works by relaxing the blood vessels, allowing them to widen so that blood can flow more freely around the body, lowering the blood pressure. It helps angina by widening the arteries so that the heart receives an adequate blood and oxygen supply. This prevents chest pain from occurring. 

How long does Istin take to work?

Istin will begin to work on the first day you start taking the medication. High blood pressure often does not produce symptoms so taking Istin may not make you feel any different. This does not mean the medicine isn't working so it's important to keep taking it. For angina, Istin will take a couple of weeks to take effect and you should feel a reduction in your chest pain after this time period. 

Active ingredients

Amlodipine besilate is the active ingredient within Istin.

Inactive ingredients

The other ingredients are microcrystalline cellulose, calcium hydrogen phosphate, magnesium stearate and sodium starch glycolate.

Which ingredients can cause an allergic reaction?

While a serious allergic reaction to Istin is rare, if you notice facial or lip swelling, a rash, severe dizziness or difficulty breathing you should seek immediate medical attention. If you have previously taken Istin and experience these symptoms, you should not take this medication again and let your prescribing doctor know.

How to start taking Istin?

Always follow the instructions given by your doctor or pharmacist on how to take Istin as the dosage will vary depending on why you are taking it. You can take Istin at any time of the day but it's best to stick to the same time each day. The tablets should be swallowed with a glass of water and can be taken with or without food. A liquid version can be prescribed if you have trouble swallowing pills. Always measure out the liquid correctly using the plastic measuring spoon provided as a teaspoon or tablespoon is not accurate. 

Istin dosage

The standard dose of Istin is 5 mg per day which can be increased up to 10 mg depending on the severity of your symptoms. Your doctor will help you find the most suitable dose.

Istin side effects

Not everyone will experience the side effects listed, and some are more common than others. 

Common or very common side effects include:

• Dizziness
• Flushing
• Headaches
• Drowsiness
• Stomach pain
• Feeling or being sick 
• Swelling of the ankles
• Skin reactions
• Palpitations (the sensation of a pounding or faster-than-normal heartbeat)
• Constipation or diarrhoea
• Indigestion
• Breathlessness
• Muscle cramps
• Disorders of vision

More than 1 in 100 people will experience these side effects, which usually subside after the first few weeks. 

Uncommon side effects (occur in less than 1 in 100 people) include

• Angioedema (a rapid onset swelling of the skin)
• Erectile dysfunction
• Gum swelling
• Numb extremities
• Fainting
• Hair loss
• Anxiety
• Arrhythmia (unusual heart rhythm)
• Chest pain
• Cough
• Dry mouth
• Gynaecomastia (breast enlargement)
• Increased sweating
• Low blood pressure
• Difficulty sleeping
• Tiredness
• Changes in mood, including depression
• Runny nose
• Changes in taste
• Tinnitus (a ringing in the ears)
• Tremor
• Urinary disorders
• Weight change

Rare or very rare side effects include:

• Confusion
• Liver dysfunction
• High blood sugar
• Hypersensitivity
• Changes to blood counts
• Heart attack
• Pancreatitis
• Sensitivity to sunlight
• Stevens-Johnson syndrome (a skin disorder characterised by a blotchy rash)
• Vasculitis (inflammation of the vessels, causing a rash)

Serious side effects, which would necessitate medical attention include: 

• Severe stomach pain, bloody diarrhoea, feeling sick, and vomiting are signs of pancreatitis.
• Jaundiced skin (yellowing of the eyes or skin) 
• Chest pain
• Allergic reaction - which may involve an itchy rash, wheeze, trouble breathing, tightness in the throat or chest, or swelling of the face

Contraindications

Istin is not suitable for the following groups of people:

• Those who are allergic to amlodipine or any of the excipients
• Children younger than six
• Pregnant women or women who are breastfeeding
• Those with severe low blood pressure (hypotension)
• Those with unstable heart failure following a heart attack
• Those with certain heart valve problems (e.g. aortic stenosis)
• People with liver or kidney disease or if you have suffered from a heart attack recently or have heart failure.

You should tell your doctor if any of the following apply:

• You have liver problems
• You have kidney problems
• You have had a heart attack recently
• You have any heart conditions including valvular heart disease or heart failure
• You have had a reaction to other medicines in the past
• You are over 65

Drug interactions

You should inform your doctor of any other medications you are taking, in particular: 

• Antibiotics e.g. erythromycin, clarithromycin and rifampicin
• Antifungals such as itraconazole or ketoconazole
• HIV or hepatitis C medications
• Anti-epileptics
• Tacrolimus or ciclosporin which reduce your immune response
• Simvastatin to reduce cholesterol
• St John’s Wort, a herbal remedy used for mental health problems

How to cope with Istin side effects?

You may experience headaches in the first week of taking Istin. These should disappear but staying hydrated and using painkillers will help. If you feel dizzy or experience a pounding heartbeat after taking it, sit or lie down until the symptoms ease off. Try to take it at times where you are able to sit down and rest. Reducing your caffeine, alcohol and smoking intake can help to ease a pounding heartbeat, as can eating smaller meals. Sitting with your legs raised will ease swollen ankles and staying cool and avoiding hot caffeinated drinks should reduce facial flushing.

Istin and pregnancy

Istin is not suitable for pregnant or breastfeeding women. If you are pregnant or planning a family, then discuss this with your doctor who will be able to prescribe a medication to treat high blood pressure that is safe for you to use.

Will Istin affect my fertility?

Taking Istin will not have an effect on your fertility. However, there is a possibility that calcium blockers like Istin may alter sperm parameters.

Lifestyle changes to make when taking Istin

There are many positive changes you can make alongside your Istin medication to help improve your blood pressure and maintain good health. Eating a healthy diet that's low in salt and saturated fats, stopping smoking, cutting down on alcohol and keeping active are some major examples. If you are overweight, a good diet and exercise can help you to reach a healthier weight, another factor which can help high blood pressure. 

Istin vs Amlodipine

Amlodipine is the generic version of the medicine. Istin is a branded version of Amlodipine. 

Istin vs other ACE inhibitors

Istin is a calcium channel blocker that works differently to ACE inhibitors. Both are effective in treating high blood pressure but there are several factors that will determine which type of medicine is most suitable for you. ACE inhibitors are more likely to be prescribed to patients under the age of 55.

Istin vs other high blood pressure medication

There are lots of factors that influence which type of high blood pressure medication is best for you. These include age, ethnicity, medical history and any other medical conditions you may have. Istin is a calcium channel blocker and the other types of medication available for high blood pressure include ACE inhibitors, angiotension receptor blockers, beta-blockers and diuretics.

Will I need to take Istin forever?

It's likely that you will need to take Istin for life as this is a long term treatment for managing high blood pressure and preventing a heart attack or stroke in the future. 

Is long term use of Istin safe?

Istin is designed for long term use so it is safe to take it in this manner. It's important to keep taking your medication, unless your doctor tells you otherwise, even if you feel well otherwise your blood pressure is likely to rise again. 

Can I stop taking Istin if my blood pressure is lower?

When your blood pressure lowers and reaches a normal level, you should continue to take your Istin medication. Stopping the medicine may reverse the effects and result in your blood pressure going up again. As a general rule, you should keep taking Istin unless you are told by your doctor to stop.

Can I stop taking Istin if I change my lifestyle?

Istin combined with a healthy lifestyle is the best thing you can do for high blood pressure. While you are taking Istin, your doctor will regularly monitor your blood pressure to find out how well the medicine is working. Most people will take Istin for life but your doctor will assess your condition and individual health to determine what is most suitable for you.

Is Istin addictive?

Istin is not addictive. 

Can I take Istin before surgery?

You can usually continue to take Istin as usual before surgery. If you are taking other types of medication for high blood pressure like ACE inhibitors and angiotensin receptor blockers then you may be asked to stop taking these 24 hours before you are due to have surgery.