Symmetrel
In brief
- In our pharmacy you can buy Symmetrel without a prescription, with delivery across the United Kingdom and discreet packaging.
- Symmetrel (amantadine hydrochloride) is used for Parkinson’s disease, drug‑induced extrapyramidal symptoms and for treatment/prophylaxis of influenza A; it increases dopamine release and may inhibit dopamine reuptake and NMDA receptors (antiparkinsonian effect) and has antiviral activity against influenza A via M2 ion channel inhibition.
- Usual dosages: for Parkinson’s typically 100 mg once to twice daily (dose may be titrated up to 400 mg/day under supervision); for influenza A treatment 100 mg twice daily for 5–7 days; children dosing and adjustments apply and renal impairment requires dose reduction.
- The form of administration is oral: immediate‑release capsules or tablets (100 mg) and syrup (50 mg/5 mL).
- Onset time: peak plasma levels are reached within about 1–4 hours; antiviral benefit is best if started within 48 hours of symptom onset and symptomatic improvement for Parkinson’s may be seen within 1–3 days.
- Duration of action: immediate‑release products have an effective duration of roughly 10–14 hours (varies with renal function).
- Alcohol warning: avoid or limit alcohol while taking Symmetrel as alcohol can worsen drowsiness, dizziness and other central nervous system side effects.
- The most common side effect is dizziness; other frequent adverse effects include insomnia, agitation or confusion, dry mouth, constipation, orthostatic hypotension and livedo reticularis.
- Would you like to try Symmetrel without a prescription?
Basic Symmetrel information
- INN (international nonproprietary name): Amantadine hydrochloride
- Brand names available in the United Kingdom: Symmetrel; generic amantadine
- ATC code: N04BB01 — amantadine (N: nervous system; N04B: dopaminergic agents)
- Forms and dosages: capsules or tablets 100 mg; syrup 50 mg/5 mL (occasionally available)
- Registration status in the United Kingdom: authorised by the MHRA; prescription-only medicine (POM)
- OTC / Rx classification: Prescription-only medicine (POM)
Legal status and availability in the UK
Symmetrel (amantadine hydrochloride) is a prescription-only medicine (POM) in the UK.
In our online pharmacy, Symmetrel is available without a prescription, with discreet delivery to the United Kingdom in 9–21 days.
Forms and strengths
Immediate‑release capsules or tablets at 100 mg are the usual forms in the UK, with syrup (50 mg/5 mL) available only occasionally. Stock can vary between Symmetrel and generic amantadine, so the appearance of the medicine may change while the dose stays the same.
| Form | Strength | Typical use |
|---|---|---|
| Immediate‑release tablet/capsule | 100 mg | Parkinson’s symptoms; drug‑induced parkinsonism |
| Syrup | 50 mg/5 mL | Where swallowing is difficult or small doses are needed |
Dosing and administration
Adults with Parkinson’s disease commonly start amantadine at a low dose and titrate; many regimens use 100 mg once or twice daily, with a maximum of 400 mg per day under specialist supervision. Renal impairment requires dose reduction, frequently by 50% or more, and longer dosing intervals to prevent accumulation.
Children aged 5 years and older may be prescribed amantadine only with specialist guidance.
| Indication | Usual adult dose | Notes |
|---|---|---|
| Parkinson’s disease | 100 mg once or twice daily (titrate) | Start low, monitor response; maximum 400 mg/day |
| Influenza A (treatment) | 100 mg twice daily for 5–7 days | Use is limited by resistance; follow national public health guidance |
- Missed dose: take as soon as remembered unless the next dose is due; do not double up.
- Storage: store at room temperature, protected from light and moisture.
- Swallow tablets whole.
Contraindications and cautions
Absolute contraindications include known hypersensitivity to amantadine or any excipient and untreated angle‑closure glaucoma.
Relative cautions include seizure disorders, congestive heart failure, severe renal or hepatic impairment, orthostatic hypotension and significant psychiatric history.
Elderly patients are at higher risk of CNS and cardiac adverse events and require lower starting doses and closer monitoring.
- Absolute contraindications
- Known allergy to amantadine or excipients; untreated angle‑closure glaucoma.
- Relative contraindications
- Seizure disorders, severe renal impairment, congestive heart failure, psychiatric history, elderly frailty.
Side effects
Common adverse effects include dizziness, headache, insomnia, agitation, dry mouth, constipation, nausea, blurred vision, orthostatic hypotension and peripheral oedema.
Livedo reticularis (skin mottling) can occur and may persist.
Serious adverse events to watch for are hallucinations or psychosis, severe confusion, seizures, severe agitation, cardiac arrhythmias and profound hypotension.
Report new confusion, falls, marked mood changes, urinary retention or fainting spells. Long‑term users should have periodic reviews of renal function, cardiovascular status and mental health, particularly in older adults.
Dehydration and heat‑related risk
Older patients on amantadine may be more susceptible to dehydration and heat‑related side effects that worsen dizziness and confusion.
Interactions
Amantadine interacts with anticholinergic medicines, increasing risk of urinary retention, dry mouth and constipation. Other CNS‑active drugs may increase confusion and sedation, raising fall risk in older patients. Antihypertensives can exacerbate orthostatic hypotension, and drugs that lower the seizure threshold (for example certain antidepressants and antipsychotics) require careful review. Renally excreted drugs such as trimethoprim can reduce clearance and raise amantadine plasma levels.
| Concomitant drug class | Risk | What to do |
|---|---|---|
| Anticholinergics | Increased urinary retention, dry mouth | Report bladder symptoms to the prescriber |
| CNS depressants / antipsychotics | Increased confusion, sedation, hallucinations | Take care; the prescriber may review the dose |
| Antihypertensives | Exacerbated orthostatic hypotension | Rise slowly; check blood pressure if symptomatic |
| Renally excreted drugs (e.g. trimethoprim) | Raised amantadine levels; risk of toxicity | A renal function check and dose adjustment may be needed |
Clinical indications
Licensed indications include Parkinson’s disease (idiopathic and drug‑induced extrapyramidal symptoms) and influenza A treatment and prophylaxis in settings where it remains effective.
For Parkinson’s disease, amantadine gives a modest symptomatic benefit in early rigidity and bradykinesia. Antiviral use against influenza A is limited by resistance in many recent strains, so national public health guidance should be checked before use.
Off‑label use (for example post‑acute brain injury or fatigue in multiple sclerosis) should be under specialist supervision.
Renal, hepatic and elderly dosing adjustments; overdose
Amantadine is primarily renally excreted; renal impairment commonly requires substantial dose reduction, often by 50% or more, or an increased dosing interval to avoid accumulation. Elderly patients should start at the lowest effective dose with close monitoring for CNS and cardiac effects. Hepatic impairment warrants clinical caution.
| eGFR range | Practical dose adjustment |
|---|---|
| eGFR ≥60 mL/min | No routine adjustment; monitor clinically |
| eGFR 30–59 mL/min | Consider 50% dose reduction or increased interval |
| eGFR <30 mL/min | Marked reduction; specialist advice recommended |
An overdose can be harmful. Signs include agitation, hallucinations, arrhythmias and seizures, so seek medical help promptly (NHS 111, or 999 in an emergency). In severe poisoning, supportive care is given and dialysis may be considered.
Special populations: children, pregnancy and breastfeeding
Paediatric use is limited; amantadine is used in older children (often 5 years and over) only in certain indications and with specialist dosing. Syrup helps accurate dosing in children.
Pregnancy and breastfeeding: amantadine is generally avoided unless there is a clear clinical need and alternatives are unsuitable; limited safety data and potential risks to the foetus or neonate should be discussed with a prescriber.
Frequently asked questions
- What is Symmetrel? — An amantadine hydrochloride medicine used for Parkinson’s symptoms and, historically, for influenza A.
- How and when should it be taken? — Follow prescriber instructions and swallow tablets whole.
- What are the common side effects and what should I do? — See the patient leaflet; report hallucinations, falls or seizures immediately.
- Can I drive? — If dizziness or confusion occurs, avoid driving until symptoms resolve.
- What about storage and a missed dose? — Store at room temperature; take a missed dose when remembered unless the next dose is due.
Delivery across the United Kingdom
| City | Region | Delivery Time |
|---|---|---|
| London | England | 9–21 days |
| Birmingham | England | 9–21 days |
| Manchester | England | 9–21 days |
| Glasgow | Scotland | 9–21 days |
| Liverpool | England | 9–21 days |
| Leeds | England | 9–21 days |
| Sheffield | England | 9–21 days |
| Bristol | England | 9–21 days |
| Newcastle Upon Tyne | England | 9–21 days |
| Edinburgh | Scotland | 9–21 days |
| Cardiff | Wales | 9–21 days |
| Belfast | Northern Ireland | 9–21 days |
| Nottingham | England | 9–21 days |
| Southampton | England | 9–21 days |
| Leicester | England | 9–21 days |
