Rasagiline ratio: Uses, Dosage & Side Effects

What Is Rasagiline ratio and What Is It Used For?

Rasagiline ratio contains the active substance rasagiline (as rasagiline mesylate), a propargylamine derivative that functions as a potent, selective, and irreversible inhibitor of monoamine oxidase type B (MAO-B). MAO-B is one of two isoforms of the monoamine oxidase enzyme family and plays a central role in the oxidative deamination of dopamine within the brain. In the striatum, the brain region most severely affected in Parkinson's disease, MAO-B is responsible for approximately 80% of dopamine metabolism. By permanently inactivating MAO-B through the formation of a covalent bond with the flavin adenine dinucleotide (FAD) cofactor at the enzyme's active site, rasagiline effectively prevents dopamine degradation and increases its synaptic availability.

Rasagiline ratio is an authorised generic medicinal product. After the regulatory exclusivity period of the originator brand of rasagiline expired, several generic manufacturers received marketing authorisation for rasagiline 1 mg tablets in the European Union and other jurisdictions. To obtain such authorisation, each generic must demonstrate pharmaceutical equivalence (same active ingredient, dose, dosage form, and route of administration) and bioequivalence (comparable rate and extent of absorption) to the reference product. This means that Rasagiline ratio delivers the same amount of rasagiline into the bloodstream, in the same time frame, as the originator. Patients can therefore expect identical efficacy and a comparable safety profile.

Parkinson's disease is a progressive neurodegenerative disorder characterised by the loss of dopaminergic neurons in the substantia nigra pars compacta of the midbrain. This neuronal loss leads to a profound deficit of dopamine in the striatum, which manifests clinically as the cardinal motor symptoms of the disease: resting tremor, rigidity, bradykinesia (slowness of movement), and postural instability. The disease affects approximately 1–2% of the population over the age of 60 worldwide, with prevalence increasing sharply with age. According to the World Health Organization, the global burden of Parkinson's disease has more than doubled in the past 25 years and now affects over 8.5 million people worldwide, making it one of the fastest-growing neurological conditions globally.

By inhibiting MAO-B, rasagiline increases the concentration of dopamine in the synaptic cleft, partially compensating for the dopaminergic deficit that underlies the motor symptoms of Parkinson's disease. In addition to its enzyme-inhibitory activity, rasagiline and its major metabolite 1-aminoindan have been investigated for potential neuroprotective properties in preclinical research. Laboratory studies have suggested that rasagiline may activate anti-apoptotic pathways (including upregulation of Bcl-2 and Bcl-xL proteins), stabilise the mitochondrial membrane potential, and reduce oxidative stress. While the clinical significance of these neuroprotective effects in humans remains an area of active investigation, the ADAGIO (Attenuation of Disease Progression with Azilect Given Once-daily) trial provided some evidence that early initiation of rasagiline 1 mg daily may have disease-modifying effects, though the results were complex and not conclusive.

Rasagiline ratio is approved for two principal indications in the management of Parkinson's disease:

• Monotherapy: Rasagiline ratio can be used as initial treatment in patients with early-stage Parkinson's disease who have not yet started levodopa therapy. As monotherapy, it provides modest but clinically meaningful improvements in motor function as measured by the Unified Parkinson's Disease Rating Scale (UPDRS). The TEMPO (TVP-1012 in Early Monotherapy for Parkinson's Disease Outpatients) trial demonstrated that rasagiline 1 mg daily significantly improved total UPDRS scores compared with placebo over 26 weeks of treatment.
• Adjunct therapy with levodopa: Rasagiline ratio can be added to levodopa-based regimens in patients with more advanced Parkinson's disease who experience motor fluctuations — periods of reduced medication effectiveness known as “off” episodes. The PRESTO and LARGO clinical trials demonstrated that rasagiline 1 mg daily, added to optimised levodopa therapy, significantly reduced total daily “off” time by approximately 0.94 hours compared with placebo, while increasing “on” time without troublesome dyskinesia.

The reference rasagiline product was first approved by the European Medicines Agency (EMA) in 2005 and by the U.S. Food and Drug Administration (FDA) in 2006. Generic versions, including Rasagiline ratio, have entered the market in subsequent years following expiry of data exclusivity. Rasagiline represents a second-generation MAO-B inhibitor, offering advantages over the older compound selegiline in that it does not produce amphetamine-like metabolites and has more predictable pharmacokinetics. International guidelines from the Movement Disorder Society (MDS), the National Institute for Health and Care Excellence (NICE), and the American Academy of Neurology (AAN) all recognise MAO-B inhibitors, including rasagiline, as appropriate first-line or adjunctive treatments for Parkinson's disease.

What Should You Know Before Taking Rasagiline ratio?

Before starting Rasagiline ratio, it is essential to provide your prescriber with a complete list of all medicines, herbal products, and over-the-counter preparations that you take. Because rasagiline irreversibly inhibits MAO-B and is involved in many clinically important drug interactions, careful screening is required. The information below summarises the most important considerations for safe use, but it is not a substitute for individual medical advice.

Contraindications

Rasagiline ratio must not be used in several clearly defined situations. The primary contraindication is known hypersensitivity (allergy) to rasagiline or to any of the excipients in the formulation. Patients with a history of allergic reactions to commonly used tablet excipients — including mannitol, maize starch, pregelatinised maize starch, colloidal anhydrous silica, stearic acid, and talc — should not take Rasagiline ratio without consulting their healthcare provider.

Concomitant use with other monoamine oxidase inhibitors is contraindicated. This applies to other MAO-B inhibitors (such as selegiline and safinamide) and to MAO-A inhibitors (such as moclobemide), as well as to non-selective MAO inhibitors used historically for depression. Combining MAO inhibitors carries a serious risk of non-selective MAO inhibition that may precipitate a hypertensive crisis. At least 14 days must elapse between discontinuation of Rasagiline ratio and initiation of another MAO inhibitor, and vice versa.

Additionally, concomitant use with the following medicines is contraindicated:

• Meperidine (pethidine): Risk of severe, potentially fatal reactions including serotonin syndrome, muscular rigidity, hyperthermia, and cardiovascular collapse. At least 14 days must elapse between stopping Rasagiline ratio and starting meperidine.
• Tramadol: Similar risk of serotonin syndrome-like reactions due to tramadol's serotonergic properties; tramadol can also lower the seizure threshold.
• Methadone: Risk of serious adverse reactions, including serotonin syndrome.
• Propoxyphene: Where this analgesic is still available, it is contraindicated for the same serotonergic reasons.
• Dextromethorphan: Risk of psychosis and bizarre behaviour due to enhanced central serotonergic effects. This cough suppressant is found in many over-the-counter cold preparations.
• St. John's wort (Hypericum perforatum): Risk of serotonin syndrome due to serotonin reuptake inhibition properties.
• Cyclobenzaprine: Structurally related to tricyclic antidepressants; carries risk of serotonergic interactions.

Patients with severe hepatic impairment (Child-Pugh Class C) must not use Rasagiline ratio because impaired hepatic metabolism leads to substantially increased rasagiline plasma concentrations, which may compromise the selectivity of MAO-B inhibition. In patients with moderate hepatic impairment (Child-Pugh Class B), Rasagiline ratio should generally be avoided; if treatment is considered essential, the clinical benefit must be carefully weighed against the potential risks.

Warnings and Precautions

Several important precautions apply to all patients starting Rasagiline ratio. While rasagiline is selective for MAO-B at the recommended dose of 1 mg daily, this selectivity is dose-dependent and may be lost at higher doses. Doses exceeding the recommended amount can lead to non-selective MAO inhibition, which dramatically increases the risk of dangerous hypertensive reactions with tyramine-containing foods.

• Orthostatic hypotension: Rasagiline may potentiate the hypotensive effects of levodopa and other antiparkinsonian medications, causing dizziness or lightheadedness on standing. The risk is highest during the initial period of treatment and in elderly patients. Patients should rise slowly from sitting or lying positions and report symptoms of dizziness to their healthcare provider.
• Dyskinesia: When used as adjunct therapy with levodopa, Rasagiline ratio may increase the occurrence of dyskinesia (involuntary movements). A reduction in the levodopa dose may help manage this side effect. In clinical trials of rasagiline, the incidence of dyskinesia was higher in patients receiving rasagiline plus levodopa compared with placebo plus levodopa.
• Impulse control disorders: As with other dopaminergic medications, rasagiline may be associated with impulse control disorders including pathological gambling, hypersexuality, compulsive shopping, and binge eating. Patients and caregivers should be aware of these potential behavioural changes and report any such symptoms promptly.
• Melanoma risk: People with Parkinson's disease have an approximately two- to six-fold higher risk of developing melanoma compared with the general population. While this risk appears to be related to Parkinson's disease itself rather than to any particular medication, periodic dermatological examinations are recommended. Patients should report any suspicious or changing skin lesions.
• Hallucinations and psychotic behaviour: Dopaminergic therapy, including MAO-B inhibitors, may cause or exacerbate hallucinations and psychotic behaviour. The risk is higher in elderly patients and in those with cognitive impairment. If significant hallucinations occur, dose reduction or discontinuation of Rasagiline ratio may be necessary.
• Switching between rasagiline products: Although bioequivalence has been demonstrated, some patients are sensitive to changes in tablet appearance or excipient composition. If you have previously taken a different brand of rasagiline and are now switching to Rasagiline ratio (or vice versa), inform your pharmacist so that any practical issues, such as tablet identification or differences in packaging, can be addressed.

Pregnancy and Breastfeeding

There are no adequate and well-controlled studies of rasagiline in pregnant women. Animal reproductive toxicology studies have shown adverse effects at doses significantly higher than the human therapeutic dose, including increased post-implantation loss and decreased pup survival in rats. Given the lack of human data and the potential risks suggested by animal studies, Rasagiline ratio should not be used during pregnancy unless the potential benefit to the mother clearly justifies the potential risk to the fetus. Women of childbearing potential should be advised to use effective contraception during treatment, and any unplanned pregnancy should be reported to the prescriber promptly.

It is not known whether rasagiline or its metabolites are excreted in human breast milk. Rasagiline has been shown to inhibit prolactin secretion in animal studies, which could potentially affect lactation. Due to the potential for serious adverse reactions in breastfed infants, a decision should be made whether to discontinue breastfeeding or to discontinue Rasagiline ratio, taking into account the importance of the medication to the mother. In most clinical situations, breastfeeding should be avoided during treatment with Rasagiline ratio.

Driving and Operating Machinery

Patients taking Rasagiline ratio should exercise caution when driving or operating machinery, particularly during the initial period of treatment. Somnolence (excessive drowsiness) and rare episodes of sudden onset of sleep have been reported with dopaminergic therapies, including MAO-B inhibitors. While these events are less commonly associated with rasagiline than with dopamine agonists, patients should be informed of this risk and advised not to drive or engage in potentially hazardous activities until they have gained sufficient experience with Rasagiline ratio to assess whether it affects their alertness or motor performance.

Use in Elderly Patients

No dose adjustment is required in elderly patients. Parkinson's disease predominantly affects older adults, and the majority of patients in clinical trials of rasagiline were over 60 years of age. The safety and efficacy profile in elderly patients was consistent with that observed in the overall study population. However, elderly patients may be more susceptible to orthostatic hypotension, central nervous system side effects (such as confusion or hallucinations), and falls, and should therefore be monitored closely.

How Does Rasagiline ratio Interact with Other Drugs?

The drug interaction profile of Rasagiline ratio is determined by two pharmacological properties of rasagiline: its irreversible inhibition of MAO-B, which affects the metabolism of serotonin and catecholamines, and its hepatic metabolism via cytochrome P450 1A2 (CYP1A2), which determines its plasma concentration. Understanding both pathways is essential for safe prescribing and effective patient management.

Unlike older non-selective MAO inhibitors (such as phenelzine and tranylcypromine), rasagiline at the recommended dose of 1 mg daily is selective for MAO-B and does not significantly inhibit MAO-A. This selectivity means that the classic “cheese effect” (a hypertensive crisis triggered by tyramine-containing foods) is much less likely with rasagiline than with non-selective MAO inhibitors. However, this selectivity may be lost at higher doses, and reasonable caution with very tyramine-rich foods remains prudent.

Contraindicated Combinations

Caution-Required Interactions

Minor Interactions and Practical Considerations

The interaction between rasagiline and antidepressants deserves particular attention because depression is common in Parkinson's disease, affecting up to 40% of patients. While the prescribing information lists SSRIs and SNRIs as cautionary combinations, clinical experience suggests that many patients can safely use rasagiline with certain SSRIs under careful medical supervision. The incidence of serotonin syndrome with the combination of rasagiline and SSRIs appears to be very low based on post-marketing surveillance data of the originator product. However, the combination should only be used when the benefits outweigh the risks, and patients should be closely monitored for signs of serotonin syndrome, especially when starting or increasing the dose of either medication.

Regarding pharmacokinetic interactions, rasagiline is primarily metabolised by CYP1A2 in the liver. Strong inhibitors of CYP1A2, such as ciprofloxacin and fluvoxamine, can significantly increase rasagiline plasma concentrations, potentially leading to non-selective MAO inhibition and an increased risk of adverse effects. Patients taking Rasagiline ratio should avoid ciprofloxacin and inform their doctor if they are prescribed any fluoroquinolone antibiotic. Conversely, CYP1A2 inducers (such as tobacco smoking and omeprazole) may decrease rasagiline levels, although this is unlikely to be clinically significant given the irreversible nature of MAO-B inhibition.

Patients undergoing scheduled surgery should inform the anaesthetic team that they are taking Rasagiline ratio. Although clinical experience does not suggest a high risk of serious anaesthetic interactions, the use of opioid analgesics that interact with MAO inhibitors (such as meperidine) must be avoided. Alternative analgesics such as morphine and fentanyl are generally considered acceptable, but the choice should be made by an experienced anaesthetist familiar with the patient's complete drug regimen.

What Is the Correct Dosage of Rasagiline ratio?

Rasagiline ratio has a simple and straightforward dosing regimen. The recommended dose is 1 mg (one tablet) taken once daily by mouth. This dose applies to both indications — monotherapy in early Parkinson's disease and adjunct therapy with levodopa in advanced disease. Unlike some antiparkinsonian medications that require gradual dose titration, Rasagiline ratio can be started at the full therapeutic dose from the first day of treatment. The tablet may be taken with or without food, as food does not significantly affect the overall bioavailability of rasagiline (although it may delay the time to peak plasma concentration by approximately 35 minutes).

Adults

Children and Adolescents

Rasagiline ratio is not indicated for use in children and adolescents under 18 years of age. Parkinson's disease is predominantly a condition of older adults, and the safety and efficacy of rasagiline have not been established in the paediatric population. In the very rare cases of juvenile-onset Parkinson's disease, treatment decisions should be made by a specialist neurologist with expertise in movement disorders, and other treatment options should usually be considered first.

Elderly Patients

Hepatic Impairment

Renal Impairment

No dose adjustment is required in patients with renal impairment. Rasagiline is primarily metabolised in the liver, and renal excretion plays a minor role in its elimination. Less than 1% of the administered dose is excreted unchanged in the urine. Patients with significantly reduced kidney function can therefore take Rasagiline ratio at the standard 1 mg daily dose, although routine monitoring of overall health remains important.

Missed Dose

If you forget to take your daily dose of Rasagiline ratio, take it as soon as you remember on the same day. However, if it is already close to the time of your next scheduled dose, skip the missed dose and return to your regular dosing schedule. Do not take a double dose to make up for a missed one. Because rasagiline irreversibly inhibits MAO-B, missing a single dose is unlikely to cause a significant resurgence of symptoms, as the enzyme remains inhibited until new MAO-B is synthesised by the body (a process that takes approximately two weeks for complete enzyme regeneration). Nevertheless, consistent daily dosing is recommended for optimal symptom control.

Overdose

There is limited clinical experience with rasagiline overdose. In the event of an overdose, symptoms are likely to reflect exaggerated pharmacological effects, including agitation, irritability, headache, tremor, marked hypertension, cardiovascular collapse, and potentially serotonin syndrome-like features (especially if combined with serotonergic agents). At higher doses, rasagiline may lose its selectivity for MAO-B and also inhibit MAO-A, which would substantially increase the risk of hypertensive crisis from tyramine-containing foods consumed after the overdose. Treatment is symptomatic and supportive; there is no specific antidote. Hospitalisation and continuous monitoring of vital signs, including blood pressure and ECG, are recommended. Contact your local poison control centre or emergency medical services immediately if overdose is suspected.

What Are the Side Effects of Rasagiline ratio?

Like all medications, Rasagiline ratio can cause side effects, although not everyone experiences them. The side effect profile differs somewhat depending on whether rasagiline is used as monotherapy or as adjunct therapy with levodopa, as many of the side effects observed in adjunct therapy are related to enhanced dopaminergic stimulation. Because Rasagiline ratio is bioequivalent to the originator brand of rasagiline, the expected adverse-event profile is the same.

Clinical trials of rasagiline demonstrated that it is generally well tolerated. In the TEMPO monotherapy trial, the discontinuation rate due to adverse events was similar between the rasagiline 1 mg group (4.0%) and the placebo group (3.7%). In the PRESTO and LARGO adjunct therapy trials, the discontinuation rates were somewhat higher (approximately 5–7%) but still comparable to placebo. The most commonly reported side effects are listed below by frequency category according to international reporting conventions used in EMA and FDA labelling.

Side Effect Frequency Overview

Dyskinesia is the most commonly reported side effect when Rasagiline ratio is used alongside levodopa, occurring in up to 18% of patients in clinical trials of rasagiline compared with approximately 10% in the placebo group. This reflects enhanced dopaminergic stimulation from the combined action of levodopa and MAO-B inhibition. In most cases, dyskinesia can be managed by reducing the levodopa dose under medical supervision. Patients should inform their doctor if dyskinesia becomes troublesome, as dose adjustments can usually provide relief.

Orthostatic hypotension (a fall in blood pressure on standing) is another notable side effect, occurring more frequently in patients receiving rasagiline in combination with levodopa. Patients should change positions slowly, especially when rising from bed in the morning. Adequate fluid intake and avoiding prolonged standing may help minimise this effect. If severe or persistent orthostatic hypotension occurs, medical evaluation is recommended to rule out other contributing factors and to adjust medications as needed.

Hallucinations, while uncommon, are a recognised side effect of dopaminergic therapies in Parkinson's disease. They are more likely to occur in elderly patients, those with cognitive impairment, and those taking multiple dopaminergic medications. If hallucinations develop, a stepwise reduction in dopaminergic medications is usually recommended, and Rasagiline ratio may need to be discontinued if hallucinations persist despite other adjustments.

Patients are encouraged to report any suspected side effects via their national reporting system, such as the EMA EudraVigilance system, the FDA MedWatch programme, or the UK Yellow Card Scheme. Reporting suspected adverse reactions, even after marketing authorisation, helps to monitor the ongoing safety of all medicinal products, including generic versions like Rasagiline ratio.

How Should You Store Rasagiline ratio?

Proper storage of Rasagiline ratio is important to ensure that the medicine retains its full potency and safety throughout its shelf life. The tablets should be stored at room temperature, not exceeding 25°C (77°F). Keep the tablets in their original blister packaging until the moment of use, as this protects them from moisture and light, both of which can affect the stability of rasagiline. Avoid transferring tablets into pill organisers in advance unless you have confirmed with your pharmacist that this is appropriate for the specific generic product you are using.

Store Rasagiline ratio in a safe place out of the sight and reach of children and pets. Accidental ingestion by children could cause serious adverse effects due to the potent pharmacological activity of rasagiline, including hypertension, agitation, and serotonergic toxicity. If accidental ingestion occurs, contact your local poison control centre or emergency services immediately.

Do not use Rasagiline ratio after the expiration date (EXP) stated on the carton and on the blister strip. The expiration date refers to the last day of that month. Tablets that show signs of damage, discolouration, or unusual odour should not be used.

Do not dispose of medications by flushing them down the toilet or throwing them in household waste, as this can contaminate water supplies and harm the environment. Ask your pharmacist about proper disposal methods for medicines that are no longer needed or have expired. Many pharmacies and local authorities operate medication take-back programmes that ensure safe and environmentally responsible disposal of pharmaceutical products.

What Does Rasagiline ratio Contain?

Each Rasagiline ratio tablet contains rasagiline mesylate equivalent to 1 mg of rasagiline base as the active pharmaceutical ingredient. Rasagiline mesylate is a white to off-white crystalline powder with the chemical name (R)-N-(prop-2-yn-1-yl)-2,3-dihydro-1H-inden-1-amine methanesulfonate. The molecular formula is C₁₂H₁₃NO · CH₄O₃S, and the molecular weight is 267.34 g/mol. The (R)-enantiomer configuration is essential for the pharmacological activity, as the (S)-enantiomer is significantly less potent as a MAO-B inhibitor.

The inactive ingredients (excipients) of Rasagiline ratio serve standard pharmaceutical purposes and are similar to those used in other rasagiline tablet products. Typical excipients include:

• Mannitol: A sugar alcohol used as a diluent and filler to give the tablet its appropriate size and weight. It has a pleasant, slightly sweet taste and does not significantly affect blood glucose levels.
• Colloidal anhydrous silica: A flow agent that prevents the powder ingredients from clumping together during the manufacturing process, ensuring uniform tablet content.
• Maize starch: Used as a binder and disintegrant to help the tablet maintain its shape and then break apart appropriately when swallowed.
• Pregelatinised maize starch: A modified starch that serves as both a binder and a disintegrant, contributing to proper tablet dissolution in the gastrointestinal tract.
• Stearic acid: A lubricant that prevents the tablet mixture from sticking to manufacturing equipment during compression.
• Talc: An additional lubricant and anti-adherent used in the tableting process.

Rasagiline ratio tablets are typically round, flat, white to off-white in appearance, and do not contain lactose, gluten, or animal-derived ingredients. The exact appearance, scoring, and embossing differ from the originator brand and from other generic rasagiline products, which is normal and reflects the manufacturing identity of the generic. Patients with a known sensitivity to maize (corn) starch should inform their healthcare provider, as both maize starch and pregelatinised maize starch are present in the formulation. The complete and authoritative list of excipients for the specific batch you receive is always provided in the package leaflet enclosed with the medicine.