Dinetrel
Dopaminergic Agent for Parkinson’s Disease
Quick Facts About Dinetrel
Key Takeaways About Dinetrel
- Dopaminergic action: Dinetrel enhances dopamine release in the brain and inhibits its reuptake, helping to improve motor function in Parkinson’s disease patients
- Gradual dose increase: Treatment typically starts with 100 mg daily for the first week, then increases to 200 mg daily, with a maximum of 400 mg in certain cases
- Never stop abruptly: Sudden withdrawal can cause severe worsening of symptoms and, if taking antipsychotics, may trigger neuroleptic malignant syndrome
- Kidney function matters: Amantadine is primarily excreted by the kidneys – dose reduction is required in patients with renal impairment
- Effectiveness may wane: Some patients notice reduced benefit after several months of use – inform your doctor if this occurs rather than adjusting the dose yourself
What Is Dinetrel and What Is It Used For?
Dinetrel contains amantadine hydrochloride, a dopaminergic agent that increases levels of dopamine and other chemical messengers in the brain. It is used to treat Parkinson’s disease by improving muscle control, reducing stiffness, tremors, and shuffling gait.
Amantadine belongs to a class of medications known as dopaminergic agents. Its mechanism of action involves multiple pharmacological effects: it promotes the release of dopamine from presynaptic nerve terminals in the brain, inhibits the reuptake of dopamine back into nerve cells, and acts as a weak antagonist at N-methyl-D-aspartate (NMDA) receptors. These combined actions enhance dopaminergic neurotransmission in the basal ganglia – the region of the brain responsible for coordinating movement – which is impaired in patients with Parkinson’s disease.
Parkinson’s disease is a progressive neurodegenerative disorder characterised by the loss of dopamine-producing neurons in the substantia nigra of the brain. This dopamine deficiency leads to the characteristic motor symptoms of the disease: resting tremor, muscular rigidity (stiffness), bradykinesia (slowness of movement), and postural instability. By increasing the availability of dopamine in the brain, amantadine helps to alleviate these motor symptoms and improve the patient’s ability to carry out daily activities.
Dinetrel is typically used as an adjunct therapy in combination with other anti-Parkinson medications such as levodopa/carbidopa. It can be particularly useful for managing levodopa-induced dyskinesias – involuntary, jerky movements that can develop as a side effect of long-term levodopa therapy. The NMDA receptor antagonist properties of amantadine are thought to be particularly relevant for this anti-dyskinetic effect. Several randomised controlled trials have demonstrated that amantadine can reduce dyskinesias by 20–50% without worsening Parkinson’s symptoms.
Amantadine was originally developed in the 1960s as an antiviral agent for influenza A, and its anti-Parkinson properties were discovered serendipitously when a patient taking amantadine for influenza noticed an improvement in her Parkinson’s symptoms. Since then, amantadine has become an established treatment option in movement disorder clinics worldwide. The European Medicines Agency (EMA) and the American Academy of Neurology (AAN) recognise amantadine as an evidence-based treatment for Parkinson’s disease and levodopa-induced dyskinesias.
Amantadine may also be authorised for the treatment of other conditions not mentioned in this product information. Always consult your doctor, pharmacist, or other healthcare professional if you have additional questions, and always follow their instructions.
What Should You Know Before Taking Dinetrel?
Before starting Dinetrel, inform your doctor about all your medical conditions, especially kidney or liver disease, heart problems, epilepsy, psychiatric disorders, or glaucoma. Dinetrel is contraindicated in several conditions and should never be taken during pregnancy or breastfeeding.
Contraindications
You should not take Dinetrel if any of the following apply to you:
- Allergy to amantadine hydrochloride or any other ingredient in Dinetrel – symptoms of an allergic reaction may include skin rash, itching, swelling, or difficulty breathing
- Seizures (convulsions), such as epilepsy – amantadine may lower the seizure threshold and increase the risk of convulsions
- History of stomach or duodenal ulcers – amantadine may worsen or cause recurrence of peptic ulcer disease
- Severe kidney disease – since amantadine is primarily excreted unchanged by the kidneys, severe renal impairment can lead to dangerous drug accumulation in the body
- Pregnancy or trying to become pregnant – animal studies have shown that amantadine can cause harm to the developing foetus
- Breastfeeding – amantadine passes into breast milk and may harm the nursing infant
If any of the above apply to you, or if you are unsure, speak to your doctor or pharmacist before taking Dinetrel.
Warnings and Precautions
Talk to your doctor or pharmacist before taking Dinetrel if you have or have had any of the following conditions:
- Liver disease – although amantadine undergoes minimal hepatic metabolism, liver impairment may affect the overall handling of the drug and could require additional monitoring
- Kidney disease (mild to moderate) – your doctor may need to reduce your dose because amantadine is almost entirely excreted by the kidneys. Even mild renal impairment can significantly affect drug clearance
- Cardiovascular disease or a history of heart problems – amantadine can cause orthostatic hypotension (a drop in blood pressure when standing up), which may worsen pre-existing cardiovascular conditions
- Heart failure – amantadine may cause fluid retention and peripheral oedema (swollen ankles), which can exacerbate heart failure symptoms such as breathlessness and ankle swelling
- Psychiatric disorders, such as schizophrenia or dementia – amantadine can worsen psychotic symptoms, cause confusion, hallucinations, or agitation. Close psychiatric monitoring is essential
- Raised intraocular pressure (glaucoma) – due to its mild anticholinergic properties, amantadine can increase intraocular pressure and should be used with caution in patients with narrow-angle glaucoma
Cases of suicidal thoughts and suicidal behaviour have been reported in patients treated with amantadine. If you have thoughts of harming yourself or attempting suicide, seek medical attention immediately. Inform your doctor about any history of depression or mental health conditions before starting treatment.
Pregnancy and Breastfeeding
Dinetrel must not be taken during pregnancy or if you are trying to become pregnant. Preclinical animal studies have demonstrated that amantadine can cross the placental barrier and cause developmental abnormalities in the foetus. Although controlled human studies are limited, the available evidence is sufficient to classify amantadine as contraindicated in pregnancy.
Dinetrel must also not be taken while breastfeeding. Amantadine is excreted into breast milk and could potentially cause adverse effects in the nursing infant, including irritability, feeding difficulties, and skin rash. If you require treatment with amantadine, your doctor will advise you to discontinue breastfeeding. Discuss alternative treatment options with your doctor if you are breastfeeding or planning to breastfeed.
Driving and Operating Machinery
You are responsible for assessing whether you are fit to drive a motor vehicle or perform work requiring heightened attention. One of the factors that may affect your ability is the use of medicines, due to their effects and side effects. Dinetrel can cause blurred vision and dizziness. If you experience these symptoms, you should not drive or operate machinery until the symptoms have resolved. Read all the information in this leaflet for guidance and discuss any concerns with your doctor or pharmacist.
Lactose Content
Dinetrel capsules contain lactose monohydrate as an excipient. If you have been told by your doctor that you have an intolerance to some sugars, contact your doctor before taking this medicine. Patients with rare hereditary problems of galactose intolerance, total lactase deficiency, or glucose-galactose malabsorption should not take this medicine.
How Does Dinetrel Interact with Other Drugs?
Dinetrel can interact with several commonly used medications, including anticholinergic drugs, levodopa, antipsychotic agents, and certain diuretics. Always inform your doctor or pharmacist about all medicines you are taking, including over-the-counter products and herbal supplements.
Drug interactions can alter how Dinetrel works or increase the risk of side effects. Some interactions may require dose adjustments or additional monitoring, while others may mean that certain drug combinations should be avoided entirely. Below is a comprehensive overview of the most clinically significant interactions.
Major Interactions
The following interactions are considered clinically significant and require careful medical supervision:
| Interacting Drug | Drug Class | Effect of Interaction | Clinical Recommendation |
|---|---|---|---|
| Procyclidine | Anticholinergic | Increased anticholinergic side effects (dry mouth, constipation, urinary retention, confusion) | Monitor closely; reduce dose of one or both drugs if needed |
| Levodopa | Anti-Parkinson | Enhanced therapeutic effect but also increased risk of side effects such as dyskinesias and hallucinations | Often used in combination; dose adjustment may be required |
| Chlorpromazine, Haloperidol | Antipsychotics | Antipsychotics may reduce the effectiveness of amantadine; abrupt withdrawal of amantadine may trigger neuroleptic malignant syndrome | Avoid abrupt discontinuation of amantadine; monitor for NMS symptoms |
| Hydrochlorothiazide, Amiloride, Triamterene | Diuretics | Reduced renal clearance of amantadine, leading to increased blood levels and risk of toxicity | Monitor for signs of amantadine toxicity; dose reduction may be necessary |
Other Interactions
The following interactions are generally less severe but should still be discussed with your doctor:
- Anticholinergic antispasmodic agents (e.g. hyoscine): Used for treating stomach cramps and spasms. Combining with Dinetrel may increase anticholinergic side effects such as dry mouth, blurred vision, and constipation. Your doctor may need to adjust the dose of either medication.
- Other dopaminergic medications: If you are taking other drugs that increase dopamine levels in the brain, the combination with amantadine may enhance both therapeutic and adverse effects. Your doctor will carefully balance the doses of all dopaminergic medications.
- Drugs affecting renal function: Any medication that impairs kidney function can reduce the clearance of amantadine and lead to drug accumulation, increasing the risk of side effects. Examples include nonsteroidal anti-inflammatory drugs (NSAIDs), ACE inhibitors, and aminoglycoside antibiotics.
- Memantine: Both amantadine and memantine are NMDA receptor antagonists. Using them together may increase the risk of central nervous system adverse effects including confusion, hallucinations, and dizziness.
Alcohol
Do not drink alcohol while taking Dinetrel. Alcohol can significantly increase the risk of central nervous system side effects including dizziness, confusion, drowsiness, and impaired coordination. The combination of amantadine and alcohol may also increase the risk of overdose. If you have questions about alcohol consumption during treatment, consult your doctor or pharmacist.
What Is the Correct Dosage of Dinetrel?
Always take Dinetrel exactly as your doctor has told you. The usual starting dose for Parkinson’s disease is 100 mg once daily during the first week, increasing to 200 mg daily. Higher doses up to 400 mg daily may be used in some cases. Elderly patients typically take 100 mg once daily.
The dosage of Dinetrel is individualised based on your condition, response to treatment, kidney function, and whether you are taking other Parkinson’s medications. Your doctor will determine the most appropriate dose for you. Swallow the capsules whole with water – do not open, crush, or chew the capsules.
Adults
Standard Adult Dosage for Parkinson’s Disease
Week 1: 1 capsule (100 mg) once daily
From week 2 onwards: 2 capsules (200 mg) daily, usually taken as one capsule in the morning and one capsule in the afternoon or evening
Maximum dose: Up to 4 capsules (400 mg) daily in divided doses, in some cases as determined by your doctor
The gradual dose escalation is important to minimise the risk of side effects such as dizziness, confusion, and gastrointestinal disturbances. Your doctor will assess your response after the first week and decide whether to increase the dose. Do not increase your dose without medical advice.
Elderly Patients (Over 65 Years)
Elderly Dosage
Recommended dose: 1 capsule (100 mg) once daily
Elderly patients are more susceptible to the side effects of amantadine, particularly confusion, hallucinations, and falls due to orthostatic hypotension. A lower maintenance dose is therefore recommended, and dose increases should be made cautiously under close medical supervision.
Patients with Kidney Problems
Since amantadine is predominantly excreted by the kidneys in unchanged form, kidney function has a significant impact on how the body processes the drug. If you have kidney problems, your doctor may prescribe a lower dose or extend the interval between doses to prevent drug accumulation and toxicity. Your kidney function will be monitored through regular blood tests during treatment.
| Kidney Function | Creatinine Clearance | Recommended Dose |
|---|---|---|
| Normal | >80 mL/min | 100–200 mg daily (standard dose) |
| Mild impairment | 50–80 mL/min | 100 mg daily or as directed |
| Moderate impairment | 30–50 mL/min | 100 mg every 48 hours or as directed |
| Severe impairment | <30 mL/min | Contraindicated – do not use |
Missed Dose
If you forget to take a dose at the correct time, take the missed dose as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a forgotten dose, as this increases the risk of side effects and potential toxicity.
Overdose
If you have taken more Dinetrel than you should, or if a child has accidentally swallowed the medicine, contact your doctor, hospital, or poison control centre immediately for risk assessment and advice. Show any remaining capsules or the empty package to the attending physician. Symptoms of amantadine overdose may include nausea, vomiting, hyperexcitability, tremor, confusion, hallucinations, seizures, and cardiac arrhythmias. Severe overdose can be life-threatening and requires urgent medical treatment.
Do not stop taking Dinetrel suddenly, as your Parkinson’s symptoms may worsen significantly. If you and your doctor decide to stop treatment, the dose should be reduced gradually over several weeks. If you are also taking antipsychotic medication and stop Dinetrel abruptly, you may develop neuroleptic malignant syndrome – a potentially life-threatening condition characterised by fever, sweating, rapid heartbeat, severe muscle rigidity, and loss of bladder control. Seek immediate medical attention if any of these symptoms occur.
Reduced Effectiveness Over Time
Some patients may notice that the beneficial effects of Dinetrel begin to diminish after several months of regular use. This phenomenon, sometimes referred to as “drug tolerance,” is well recognised with amantadine. If you feel that the medicine is becoming less effective, inform your doctor. Do not increase the dose on your own. Your doctor may consider adjusting your treatment regimen, which could involve temporarily discontinuing amantadine and restarting it after a break (a “drug holiday”), adjusting the doses of other Parkinson’s medications, or switching to an alternative treatment.
What Are the Side Effects of Dinetrel?
Like all medicines, Dinetrel can cause side effects, although not everybody gets them. Side effects are often mild and may resolve after a few days of treatment. The most common side effects are swollen ankles and red skin patches. Seek immediate medical attention if you experience dizziness, confusion, fainting, or seizures.
The following information categorises the possible side effects of Dinetrel by their frequency of occurrence, as observed in clinical studies and post-marketing surveillance. Understanding the frequency helps you and your doctor weigh the benefits of treatment against the potential risks. If side effects are severe or persist for more than a few days, contact your doctor or pharmacist.
Dizziness or confusion, fainting, or seizures (convulsions). These may be signs of a serious adverse reaction that requires urgent medical assessment.
Very Common
May affect more than 1 in 10 people
- Swollen ankles (peripheral oedema) – caused by fluid retention
- Red skin patches (livedo reticularis) – a mottled, net-like purplish discolouration of the skin, usually on the legs
Common
May affect up to 1 in 10 people
- Anxiety and excessive euphoria
- Depression
- Insomnia (difficulty sleeping) and nightmares
- Confusion and difficulty concentrating
- Headache and fatigue
- Difficulty controlling movements (dyskinesias)
- Slurred speech
- Nervousness and muscle pain
- Hallucinations (seeing or hearing things that are not there)
- Rapid or irregular heartbeat (palpitations, tachycardia)
- Low blood pressure when standing up (orthostatic hypotension) – may cause dizziness or fainting
- Dry mouth and loss of appetite
- Nausea or vomiting
- Constipation
- Excessive sweating
Uncommon
May affect up to 1 in 100 people
- Blurred vision
Rare
May affect up to 1 in 1,000 people
- Disorientation (not knowing where you are)
- Thought or behaviour disturbances, such as delusions
- Tremors and movement difficulties
- Neuroleptic malignant syndrome (NMS) – may cause a sensation of warmth and severe muscle rigidity
- Diarrhoea
- Skin rash
- Eye problems such as itching, redness, corneal ulcers, corneal oedema, and reduced visual acuity
- Loss of bladder control (urinary incontinence or urinary urgency)
Very Rare
May affect up to 1 in 10,000 people
- Heart problems that may cause breathlessness or swollen ankles (cardiac failure)
- Decreased white blood cell count (leukopenia) – increasing susceptibility to infections
- Changes in liver function blood tests
- Sensitivity to sunlight (photosensitivity)
Not Known
Frequency cannot be estimated from available data
- Impulse control disorders – a strong urge to engage in excessive gambling, altered or increased sexual interest, uncontrollable compulsive shopping or spending, or binge eating
- Delirium (acute confusional state)
- Hypomania and mania (increased energy, self-confidence, and feelings of wellbeing; pathological excitement)
If you experience any side effects, talk to your doctor or pharmacist. This includes any possible side effects not listed above. You can also report side effects directly to your national pharmacovigilance authority. By reporting side effects, you can help provide more information on the safety of medicines.
How Should You Store Dinetrel?
Store Dinetrel below 25°C in the original packaging. Keep out of sight and reach of children. Do not use after the expiry date printed on the blister and carton.
Proper storage of medication is essential to maintain its efficacy and safety throughout its shelf life. Follow these guidelines for storing Dinetrel:
- Temperature: Store at or below 25°C (77°F). Avoid exposure to excessive heat, direct sunlight, or moisture. Do not store in the bathroom.
- Child safety: Keep Dinetrel out of the sight and reach of children at all times. Consider using a lockable medicine cabinet if children are present in the household.
- Expiry date: Do not use this medicine after the expiry date stated on the blister pack and carton after “EXP.” The expiry date refers to the last day of that month.
- Disposal: Do not throw away medicines via wastewater or household waste. Ask your pharmacist how to dispose of medicines you no longer use. These measures help to protect the environment.
What Does Dinetrel Contain?
Each Dinetrel capsule contains 100 mg of amantadine hydrochloride as the active ingredient, along with lactose monohydrate, povidone, and magnesium stearate as excipients. The capsules are dark reddish-brown hard gelatin capsules marked AM100.
Active Ingredient
The active substance in Dinetrel is amantadine hydrochloride. Each hard gelatin capsule contains 100 mg of amantadine hydrochloride, which is equivalent to approximately 74.5 mg of amantadine base.
Other Ingredients (Excipients)
The other ingredients in Dinetrel are:
- Capsule contents: Lactose monohydrate, povidone (E1201), and magnesium stearate (E470b)
- Capsule shell: Gelatin, titanium dioxide (E171), sodium lauryl sulphate, and red iron oxide (E172)
- Printing ink (white): Shellac (E904), titanium dioxide (E171), and propylene glycol (E1520)
Appearance and Pack Sizes
Dinetrel capsules are dark reddish-brown, hard gelatin capsules (size 3) with white printing “AM100” on both the cap and body of the capsule. The capsules are packed in PVC/PVdC-aluminium blisters. Pack sizes available: 5, 7, 10, 14, 28, 30, and 56 capsules. Not all pack sizes may be marketed in your country.
Frequently Asked Questions About Dinetrel
Dinetrel (amantadine) is primarily used to treat Parkinson’s disease. It helps improve muscle control, reduces stiffness, tremors, and shuffling gait by enhancing dopamine signalling in the brain. Amantadine works by increasing the release of dopamine from nerve cells and blocking its reuptake, resulting in more dopamine being available in the parts of the brain that control movement. It is often used as an adjunct therapy alongside other Parkinson’s medications such as levodopa.
The most common side effects of Dinetrel include swollen ankles (peripheral oedema) and red skin patches (livedo reticularis), which occur in more than 1 in 10 people. Other common side effects affecting up to 1 in 10 people include anxiety, insomnia, confusion, nightmares, headache, fatigue, difficulty controlling movements, hallucinations, rapid or irregular heartbeat, dry mouth, loss of appetite, nausea, constipation, and sweating. Most side effects are mild and may improve after a few days of treatment.
No, you should never stop taking Dinetrel suddenly. Abrupt discontinuation can cause a dangerous worsening of your Parkinson’s symptoms. If you are also taking antipsychotic medication and stop Dinetrel abruptly, you may develop neuroleptic malignant syndrome (NMS) – a potentially life-threatening condition with symptoms including fever, sweating, rapid heartbeat, and severe muscle rigidity. Always consult your doctor before stopping treatment. Your doctor will advise you on how to gradually reduce the dose over several weeks.
No, you should not drink alcohol while taking Dinetrel. Alcohol can increase the risk of side effects from amantadine, including dizziness, confusion, drowsiness, and impaired coordination. The combination of alcohol and amantadine may also increase the risk of overdose. If you have questions about alcohol use during treatment, consult your doctor or pharmacist for personalised advice.
No, Dinetrel should not be taken during pregnancy or if you are trying to become pregnant. Animal studies have shown that amantadine can cause harm to the developing foetus. It should also not be used during breastfeeding because amantadine passes into breast milk and could harm the infant. If you are pregnant or planning pregnancy, discuss alternative treatment options with your doctor to find a safer approach for managing your Parkinson’s symptoms.
Some patients notice that the effectiveness of Dinetrel may diminish after several months of regular use. This is a recognised phenomenon with amantadine and does not necessarily mean the medication has stopped working entirely. Do not increase your dose without medical advice. Instead, inform your doctor, who may adjust your treatment plan by changing the dose, adding another medication, temporarily discontinuing amantadine and restarting it after a break, or considering an alternative therapy.
References & Medical Sources
This article is based on the following peer-reviewed sources and international guidelines:
- European Medicines Agency (EMA). Amantadine – Summary of Product Characteristics. EMA, 2024. Available at: www.ema.europa.eu
- Fox SH, Katzenschlager R, Lim SY, et al. International Parkinson and Movement Disorder Society Evidence-Based Medicine Review: Update on Treatments for the Motor Symptoms of Parkinson’s Disease. Movement Disorders. 2018;33(8):1248–1266. doi:10.1002/mds.27372
- Pahwa R, Factor SA, Lyons KE, et al. Practice Parameter: Treatment of Parkinson disease with motor fluctuations and dyskinesia (an evidence-based review). Neurology. 2006;66(7):983–995. American Academy of Neurology (AAN).
- National Institute for Health and Care Excellence (NICE). Parkinson’s disease in adults: diagnosis and management. NICE guideline [NG71]. Updated 2024. Available at: www.nice.org.uk/guidance/ng71
- World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd List. Geneva: WHO; 2023. Available at: www.who.int
- Connolly BS, Lang AE. Pharmacological Treatment of Parkinson Disease: A Review. JAMA. 2014;311(16):1670–1683. doi:10.1001/jama.2014.3654
- British National Formulary (BNF). Amantadine hydrochloride. BMJ Group and Pharmaceutical Press. Updated January 2026. Available at: bnf.nice.org.uk
- Ory-Magne F, Corvol JC, Azulay JP, et al. Withdrawing amantadine in dyskinetic patients with Parkinson disease: the AMANDYSK trial. Neurology. 2014;82(4):300–307. doi:10.1212/WNL.0000000000000050
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