Norvasc (Amlodipine besylate 5mg) Tablets

Norvasc general information

What is Norvasc used for?

Cardiovascular disease covers a range of heart and circulation problems, including hypertension (high blood pressure), heart failure, and angina. Coronary artery disease (CAD) is the most common form of heart disease.  It is the narrowing of blood vessels that supply the heart due to clogged arteries. Angina is a symptom of CAD, and if it gets worse, CAD can result in a heart attack.  If CAD is not treated, this can lead to heart failure, where the heart muscle becomes weakened and cannot pump efficiently.  Norvasc tablets 5mg are used to treat mild to moderate hypertension, in conjunction with other antihypertensive medicines like diuretics (water pills).  They are also used for long-term treatment of angina that has persisted for some time. 

High blood pressure

Blood pressure is a measure of the force of your heart as it pumps blood around the body, combined with the resistance of the artery walls to blood being pumped through the circulation.  Two blood pressure measurements indicate whether your blood pressure is within the normal range.  Systolic pressure measures the force generated by the heart contracting with each heartbeat to pump blood out into the arteries.  Diastolic pressure is the resting phase between each heartbeat when the heart muscle relaxes, and the heart fills with blood.  When your blood pressure is measured, it is expressed as systolic pressure (the highest measure) over diastolic pressure (the lowest measure). 

If the arteries become narrowed or constricted, this increases their resistance to blood flow, and more force is needed to pump blood around the body.  The extra strength of the blood against artery walls due to narrowing causes systemic hypertension, which is high blood pressure when your body is relaxed and at rest.  High blood pressure puts a strain on the heart by increasing its workload and its need for more oxygen.  The extra force of blood in the circulation can damage blood vessels, especially smaller blood vessels, such as those in the kidneys, leading to kidney damage.  Hypertension also increases the risk of cardiovascular disease, including stroke and heart attack.  There are usually no symptoms of hypertension, so you will only know if you have high blood pressure by having a check. 

Angina

Narrowing of the arteries is also known as atherosclerosis.  It is caused by a build-up of plaque, which is fatty deposits, mainly cholesterol.  Clogged arteries restrict blood flow to the heart, and the heart muscle becomes starved of oxygen.  However, because the arteries are not blocked completely, this does not cause permanent damage to the heart.  Angina pectoris is one of the first signs that your heart is not getting enough oxygen.  The symptoms of angina include chest pain, tightness or heaviness across the chest, breathlessness on exertion, and a feeling of discomfort like indigestion.  If this continues, the condition is known as chronic stable angina, and symptoms can be triggered by any form of exertion or emotional stress.  This condition is a warning sign that you are at increased risk of more serious problems such as a heart attack. 

Prinzmetal’s or variant angina is a rare form of angina that usually happens at night when you are at rest.  It is caused by spasm of the coronary artery, which temporarily cuts off the blood supply to your heart due to a sudden tightening of the artery wall muscle.  Symptoms can be severe but don’t usually last for long.  Triggers for Prinzmetal’s angina include exposure to the cold, drug use such as alcohol and cocaine, smoking, and certain medications like sumatriptan.

How does Norvasc work?

Norvasc tablets 5mg contain amlodipine, a calcium channel blocker that is used to treat mild to moderate hypertension and chronic stable angina. 

Calcium is needed for contraction of smooth muscle in artery walls (vasoconstriction) and also the heart muscle (myocardium).  Amlodipine in Norvasc tablets 5mg works by inhibiting calcium ions flowing into smooth muscle cells across specific calcium channels in their cell membranes.  If these calcium channels are blocked, the smooth muscle cells cannot contract as strongly, allowing arteries to relax and widen (vasodilation). 

Relaxation and widening of the arteries taking oxygenated blood to the rest of the body, decreases the resistance to blood flow in the peripheral arteries.  Reduced blood flow resistance directly affects blood pressure, allowing high blood pressure to return to normal levels.  The heart does not need to work so hard to pump blood around the body, reducing its workload and oxygen demand.  As the heart recovers its oxygen supply, angina symptoms like chest pain are also reduced, and exercise tolerance improves.

Amlodipine in Norvasc tablets 5mg also acts directly on the coronary arteries.  Widening of the heart's main arteries increases the oxygen supply to the heart, which relieves coronary artery spasm and reduces symptoms of Prinzmetal’s angina.

What does Norvasc contain?

Norvasc tablets 5mg contains the active ingredient amlodipine, a calcium channel blocker that is used to treat mild to moderate hypertension and chronic stable angina.  They also contain microcrystalline cellulose calcium hydrogen phosphate sodium starch glycollate magnesium stearate.

What are the side effects of Norvasc?

Most medications have some side effects, but they are not experienced by everyone.  Some side effects are commonly experienced when taking Norvasc, but others are not so common, and you should discuss any problems or concerns with your primary care physician. 

Common side effects when taking Norvasc include headache, oedema (swelling of the ankles, feet, face or hands), flushing, palpitations, tiredness, drowsiness, dizziness, abdominal pain, nausea.

When should Norvasc not be used?

Have a talk with your primary healthcare physician before taking Norvasc tablets 5mg so that you have a full understanding of what this medicine is for and how to use it.  There are some reasons for not taking a medication; these are called contraindications, and for Norvasc tablets 5mg you should consider the following before taking Norvasc:

• Have you ever had an unusual reaction or an allergy when taking Norvasc?
• Are you allergic to amlodipine, any other calcium channel blockers or any ingredients in Norvasc tablets?
• Are you pregnant or breastfeeding?
• Do you have any problems with your liver?
• Do you have heart problems including, congestive heart failure?
• Do you have severe hypotension (low blood pressure)?

What medications interact with Norvasc

Some medicines interact with Norvasc tablets 5mg and may affect the way it works, or are affected by Norvasc or increase side effects; you should discuss possible interactions with your primary care physician.  These may include ritonavir or telaprevir for HIV, antifungals like ketoconazole, alprostadil and sildenafil for erectile dysfunction, simvastatin for high cholesterol, antibiotics like erythromycin or clarithromycin.

If other medications may interact with Norvasc, your doctor will discuss these with you. 

How should Norvasc be taken and for how long?

You should take your Norvasc tablets 5mg swallowed whole with a glass of water, once daily, with or without food.  The dose you take and for how long should be as recommended by your doctor.  If required, your doctor may increase your dose. 

You should not drink grapefruit juice while you are taking Norvasc as this may increase the blood pressure lowering effects. 

Missed dose of Norvasc

If you miss a dose of Norvasc tablets 5mg take it as soon as you remember, unless it is time to take the next dose, then skip the missed dose.  Do not take a double dose.

How should Norvasc be stored?

You should store your Norvasc tablets 5mg below 25°C in a cool dry place.