Indications  

Symmetrel is a prescription medicine used for preventing and treating symptoms of infections caused by different strains of influenza A virus. 

Symmetrel may be prescribed as well in the treatment of Parkinsonism and drug-induced extrapyramidal reactions. 

Categorized as an adamantane antiviral, Symmetrel is believed to regulate movement issues by elevating dopamine levels in specific body regions. On the other hand, its action against the influenza A virus involves halting viral spread within the body. 

Uses and Dosage 

Before taking Symmetrel and with every prescription refill, carefully review its medication guide and patient information leaflet. Consult your healthcare provider or pharmacist for any questions or concerns. 

The dosage of this medication is determined according to the patient’s medical condition and treatment response, with consideration for body weight in children. 

Typically, Symmetrel is taken once or twice daily as prescribed by the doctor, without regard to food intake.  

If you’re on a twice-daily regimen and experience sleep difficulties post-dose, administer the second dose a few hours before bedtime. 

Optimal effectiveness of Symmetrel is achieved by maintaining a consistent level in the body. Administer this medication at evenly spaced intervals throughout the day and night. 

If this medication is taken for viral infection, take it as soon as possible and complete the full prescribed course, regardless of symptom improvement. Premature discontinuation may lead to infection recurrence. 

In Parkinson’s disease, noticeable effects from the medication might take several weeks to manifest. Abruptly discontinuing Symmetrel is not recommended, as it could exacerbate symptoms or side effects. Your physician might advise a gradual dose reduction.  

Prolonged use of this medication could potentially diminish its efficacy over months. Should its effectiveness decline, inform your doctor. 

Side Effects 

Listed below are the potential adverse effects of Symmetrel. Inform your doctor promptly if any of them persist or worsen. 

Common Side Effects 

• Dizziness 
• Nausea 
• Sleep problems (insomnia) 

Serious Side Effects 

• Breathlessness, even with slight exertion, along with hand or foot swelling 
• Painful or difficult urination 
• Depression, restlessness, or aggression 
• Altered behavior, hallucinations, self-harm ideation 
• Seizure occurrence (convulsions) 
• Pronounced nervous system reaction, including: 
  • Muscle rigidity 
  • Elevated fever 
  • Sweating 
  • Confusion 
  • Rapid or irregular heartbeats 
  • Tremors 
  • Near-fainting sensation 

Call your doctor right away if any of the serious side effects above are experienced. 

Allergic Reactions 

Although rare, a severe allergic reaction to Symmetrel may occur. Seek immediate medical help in case of any signs of an allergic reaction, such as: 

• Hives 
• Swelling of the face, lips, tongue, or throat 
• Difficulty breathing 

Not all possible side effects of Symmetrel are included in this list. Inform your doctor if any unlisted effects occur. 

Cautions 

Before starting treatment with Symmetrel, inform your doctor if you have any known allergies, particularly to: 

• Amantadine 
• Rimantadine 
• Other medicines 

Consult your pharmacist for more information about Symmetrel, as it may contain inactive ingredients that may cause allergic reactions or other complications. 

To ensure Symmetrel is safe for you, disclose to your physician your medical background, especially if you have a history of: 

• Glaucoma 
• Peripheral edema (swelling of arms/legs) 
• Heart issues (e.g., heart failure) 
• Blood pressure fluctuations (e.g., standing-related dizziness) 
• Kidney disease 
• Liver disease 
• Mental/mood disorders (e.g., depression, psychosis) 
• Seizures 
• Eczematoid dermatitis 

Inform all your healthcare providers of any current or recently started or stopped medications, including prescription/non-prescription drugs, vitamins, and herbal supplements, to lower the risk of drug interaction with Symmetrel. 

Consult your doctor before taking any diet pills, caffeine pills, or other stimulants (including ADHD medications), as combining them with Symmetrel may lead to adverse side effects. 

Symmetrel has the potential to impede the effectiveness of certain vaccines, including the nasal flu vaccine. However, a flu shot (injection-based flu vaccine) could be considered under your doctor’s guidance if advised. 

Symmetrel should not replace the annual flu shot, as its effectiveness can vary across flu seasons due to the potential resistance of certain influenza virus strains to the medication. 

The use of Symmetrel can lead to drowsiness and blurred vision. Avoid driving, operating machinery, or partaking in any potentially risky tasks until you have assessed the effects of this medication on your body. 

The use of Symmetrel may result in dizziness, lightheadedness, and fainting if one abruptly rises from lying down. This is particularly common during the initial stages of medication intake or when the dosage is raised. To prevent such complications, slowly get out of bed and rest your feet on the floor for a few minutes before standing up. 

While taking Symmetrel, heightened sexual impulses, uncommon gambling tendencies, or other intense urges might emerge. If such experiences arise, consult your doctor. 

Symmetrel should only be used when necessary during pregnancy. Consult your doctor to weigh the risks and benefits. 

Breastfeeding should be avoided while taking Symmetrel as its active ingredient (amantadine) has the potential to pass into breast milk and pose risks to the nursing baby.