Virtual Medical Centre

Drugs

Symmetrel

Generic Name: Amantadine hydrochloride
Product Name: Symmetrel

• Indication of Symmetrel
• Action of Symmetrel
• Dose Advice of Symmetrel
• Schedule of Symmetrel
• Common side effects of Symmetrel
• Uncommon side effects of Symmetrel
• Reference

Indication of Symmetrel:

Symmetrel contains the active drug amantadine which is currently used for two very different uses:

1. Treatment of Parkinson's disease- Parkinson's is a disorder of movement characterised by symptoms such as shaking of the limbs, stiffness and slowness of movement. Parkinson's disease and syndromes are caused by abnormal amounts of dopamine and acetylcholine within the brain. Symmetrel either alone or in combination with other medications helps to restore this balance of chemicals. Thus it releives many of the symptoms of Parkinson's disease but does not cure the disease.
2. Prevention of influenza (the flu)- Symmetrel is given to people who are at risk of serious disease from the flu who have not been immunised. This includes patients with disorders such as chronic respiratory diseases or diabetes mellitus. Symmetrel only covers one strain of influenza (type A). It can only be used to prevent the flu and is of no benefit if you have already caught the infection.

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Action of Symmetrel:

The exact mechanism of Symmetrel is not entirely understood. However, as previously mentioned, it is thought to act by restoring the abnormal levels of dopamine and acetylcholine in the central nervous system. These are both important chemicals that control movement. Symmetrel works by increasing the production of dopamine from specialised nerve cells and by blocking acetylcholine receptors. This improves the signs and symptoms of Parkinson's disease and will help restore your functional ability. These effects usually occur one to two days after starting the drug.

To prevent influenza, Symmetrel acts by inhibiting replication of the virus and preventing the viral RNA from entering cells. It only prevents the disease and does not change the immune response your body makes when treating the infection.

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Dose Advice of Symmetrel:

Precautions

• You should not take Symmetrel if you are pregnant as it may have adverse effects on the growing fetus. In addition, Symmetrel is not recommended during breast feeding as it can pass from the milk to your baby.
• You should not take Symmetrel if you allergic to amantadine hydrochloride or any of the non-active ingredients of the capsules (rape seed oil, lecithin, wax blend of white beeswax, soya and vegetable oils, sodium ethyl hydroxybenzoate, gelatin, glycerol, iron oxide red, sorbitol, sodium propyl hydroxybenzoate, titanium dioxide).
• Before taking Symmetrel, tell your doctor of any medical condidtions you have, in particular kidney disease, liver disease, epilepsy, mental disorders, heart disease, stomach ulcers, low blood pressure, glaucoma, prostate trouble or recurring eczema. These conditions may increase your risk of side effects so your doctor may need to prescribe a lower dose or provide extra precautions throughout your treatment.
• Let your doctor know all medications you are taking (including those bought in supermarkets and chemists) as some drugs can interact with Symmetrel. In particular, drugs affecting the central nervous system such as alcohol can interact.
• Be careful driving and operating machinery whilst taking Symmetrel as it can cause dizziness and affect your vision. It is best to avoid these activities until you are sure of the effects of the drug on your body.
• Whilst taking Symmetrel try to stand or rise slowly. If you stand up quickly, you may fell faint or lightheaded due to a rapid fall in blood pressure.
• Also try to avoid excessive sunlight and wear sunscreen in the sun as Symmetrel can increase your skin's sensitivity and may cause a skin rash, itching, redness or severe sunburn.
• Always take Symmetrel as prescribed by your doctor (see below). Do not stop this drug suddenly as you may ge withdrawal symptoms such as fever, muscle rigidity, sweating, agitation, rapid breathing and increased heart rate. If you do need to cease this medication, your doctor will help you gradually reduce your dose before stopping it completely.

Dosage

Symmetrel is currently available as soft brown gelatin capsules containing 100mg of the active component- amantadine hydrochloride. Packets contain 100 capsules. The usual doses vary according to age and your estimated renal function (as this alters the eliminations of the drug):

• For Parkinson's disease in adults up to 65 years the usual starting dose is one capsule (100mg) each day, increasing after a week to one capsule twice each day.
• For Parkinson's disease in adults over 65 years the dose is one capsule (100mg) daily.
• For Type A influenza in children and adults aged 10 to 65 years, the usual dose is one capsule twice each day. This should be commenced as soon as possible after exposure to the flu virus and continued for 10 days. If side effects occur your dose may be reduced to one capsule each day. Children aged 5 to 9 and adults over 65 years old usually take only one capsule each day.
• If you have impaired kidney function, your doctor will alter your dosing interval to one capsule every 2-7 days. This should reduce side effects from the drug.

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