Rizalt

Acute treatment of the headache phase of migraine attacks, with or without aura in adults.

Rizaltriptan Orodispersible Tablets should not be used prophylactically.

Posology

Adults 18 years of age and older

The recommended dose is 10 mg daily.

Other medicinal products in a lower strength (5mg) are available and should be used by those patients requiring a lower dose.

Redosing: doses should be separated by at least two hours; no more than two doses should be taken in any 24-hour period.

- for headache recurrence within 24 hours: if headache returns after relief of the initial attack, one further dose may be taken. The above dosing limits should be observed

- after non-response: the effectiveness of a second dose for treatment of the same attack, when an initial dose is ineffective, has not been examined in controlled trials. Therefore, if a patient does not respond to the first dose, a second dose should not be taken for the same attack.

Clinical studies have shown that patients who do not respond to treatment of an attack are still likely to respond to treatment for subsequent attacks.

Some patients should receive the lower (5 mg) dose of Rizaltriptan Orodispersible Tablets, in particular the following patient groups:

− patients on propranolol. Administration of Rizaltriptan should be separated by at least two hours from administration of propranolol..

− patients with mild or moderate renal insufficiency.

− patients with mild to moderate hepatic insufficiency.

Doses should be separated by at least two hours; no more than two doses should be taken in any 24-hour period.

Patients older than 65 years

The safety and efficacy of Rizaltriptan in patients older than 65 years have not been systematically evaluated.

Paediatric population

The safety and efficacy of Rizaltriptan in children and adolescents under 18 years of age has not yet been established.

Method of administration.

For oral use.

Effects of food: Onset of effect may be delayed when Rizaltriptan is administered in the fed state..

Rizaltriptan Orodispersible Tablets need not be taken with liquid.

Rizaltriptan Orodispersible Tablets are packaged in a perforated unit dose blister. Patients should be instructed to peel open the blister pack with dry hands and to place the orodispersible tablet on the tongue, where it will dissolve and be swallowed with the saliva.

Orodispersible Tablets can be used in situations in which liquids are not available, or to avoid the nausea and vomiting that may accompany the ingestion of tablets with liquids.

Concurrent administration of monoamine oxidase (MAO) inhibitors or use within two weeks of discontinuation of MAO inhibitor therapy.

Patients with severe hepatic or severe renal insufficiency.

Patients with a previous cerebrovascular accident (CVA) or transient ischemic attack (TIA).

Moderately severe or severe hypertension, or untreated mild hypertension.

Established coronary artery disease, including ischemic heart disease (angina pectoris, history of myocardial infarction, or documented silent ischaemia), signs and symptoms of ischemic heart disease, or Prinzmetal's angina.

Peripheral vascular disease.

Concomitant use of Rizaltriptan and ergotamine, ergot derivatives (including methysergide), or other 5-HT_1B/_1D receptor agonists.

Rizaltriptan should only be administered to patients in whom a clear diagnosis of migraine has been established. Rizaltriptan should not be administered to patients with basilar or hemiplegic migraine.

Rizaltriptan should not be used to treat 'atypical' headaches, i.e. those that might be associated with potentially serious medical conditions, (e.g. CVA, ruptured aneurysm) in which cerebrovascular vasoconstriction could be harmful.

Rizaltriptan can be associated with transient symptoms including chest pain and tightness which may be intense and involve the throat. Where such symptoms are thought to indicate ischaemic heart disease, no further dose should be taken and appropriate evaluation should be carried out.

As with other 5-HT_1B/1D receptor agonists, Rizaltriptan should not be given, without prior evaluation, to patients in whom unrecognised cardiac disease is likely or to patients at risk for coronary artery disease (CAD) [e.g. patients with hypertension, diabetics, smokers or users of nicotine substitution therapy, men over 40 years of age, post-menopausal women, patients with bundle branch block, and those with strong family history for CAD]. Cardiac evaluations may not identify every patient who has cardiac disease and, in very rare cases, serious cardiac events have occurred in patients without underlying cardiovascular disease when 5-HT₁ agonists have been administered. Those in whom CAD is established should not be given Rizaltriptan.

5-HT_1B/1D receptor agonists have been associated with coronary vasospasm. In rare cases, myocardial ischaemia or infarction have been reported with 5-HT_1B/1D receptor agonists including Rizaltriptan.

Other 5-HT_1B/1D agonists, (e.g. sumatriptan) should not be used concomitantly with Rizaltriptan.

It is advised to wait at least six hours following use of Rizaltriptan before administering ergotamine-type medications (e.g. ergotamine, dihydro-ergotamine or methysergide). At least 24 hours should elapse after the administration of an ergotamine-containing preparation before Rizaltriptan is given. Although additive vasospastic effects were not observed in a clinical pharmacology study in which 16 healthy males received oral Rizaltriptan and parenteral ergotamine, such additive effects are theoretically possible.

Serotonin syndrome (including altered mental status, autonomic instability and neuromuscular abnormalities) has been reported following concomitant treatment with triptans and selective serotonin reuptake inhibitors (SSRIs) or serotonin noradrenaline reuptake inhibitors (SNRIs). These reactions can be severe. If concomitant treatment with Rizaltriptan and an SSRI or SNRI is clinically warranted, appropriate observation of the patient is advised, particularly during treatment initiation, with dose increases, or with addition of another serotonergic medication.

Undesirable effects may be more common during concomitant use of triptans (5-HT_1B/1D agonists) and herbal preparations containing St John's wort (Hypericum perforatum).

Angioedema (e.g. facial oedema, tongue swelling and pharyngeal oedema) may occur in patients treated with triptans, among which is Rizaltriptan. If angioedema of the tongue or pharynx occurs, the patient should be placed under medical supervision until symptoms have resolved. Treatment should promptly be discontinued and replaced by an agent belonging to another class of drugs.

The potential for interaction should be considered when Rizaltriptan is administered to patients taking CYP 2D6 substrates.

Medication overuse headache (MOH)

Prolonged use of any painkiller for headaches can make them worse. If this situation is experienced or suspected, medical advice should be obtained and treatment should be discontinued. The diagnosis of MOH should be suspected in patients who have frequent or daily headaches despite (or because of) the regular use of headache medications.

Phenylketonurics: Phenylketonuric patients should be informed that phenylalanine may be harmful. Rizaltriptan Orodispersible Tablets contain aspartame (which contains phenylalanine). Each 10 mg Rizaltriptan Orodispersible Tablet contains 10 mg aspartame.

Migraine or treatment with Rizaltriptan Orodispersible Tablets may cause somnolence in some patients. Dizziness has also been reported in some patients receiving Rizaltriptan. Patients should, therefore, evaluate their ability to perform complex tasks during migraine attacks and after administration of Rizaltriptan Orodispersible Tablets.

Summary of the safety profile

Rizaltriptan was evaluated in over 8,630 patients for up to one year in controlled clinical studies. The most common undesirable effects evaluated in clinical studies were dizziness, somnolence, and asthenia/fatigue.

The following undesirable effects have been evaluated in clinical studies and/or reported in post-marketing experience:

(Very common [> 1/10]; Common [>1/100 to <1/10]; Uncommon: [>1/1,000 to <1/100]; Rare [>1/10,000 to <1/1,000]; Very rare [<1/10,000], not known [cannot be estimated from the available data]).

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard

Rizaltriptan 40 mg (administered as either a single dose or as two doses with a two-hour interdose interval) was generally well tolerated in over 300 adult patients; dizziness and somnolence were the most common drug-related adverse effects.

In a clinical pharmacology study in which 12 subjects received Rizaltriptan, at total cumulative doses of 80 mg (given within four hours), two subjects experienced syncope and/or bradycardia. One subject, a female aged 29 years, developed vomiting, bradycardia, and dizziness beginning three hours after receiving a total of 80 mg Rizaltriptan (administered over two hours). A third-degree AV block, responsive to atropine, was observed an hour after the onset of the other symptoms. The second subject, a 25 year-old male, experienced transient dizziness, syncope, incontinence, and a five-second systolic pause (on ECG monitor) immediately after a painful venipuncture. The venipuncture occurred two hours after the subject had received a total of 80 mg Rizaltriptan (administered over four hours).

In addition, based on the pharmacology of Rizaltriptan, hypertension or other more serious cardiovascular symptoms could occur after overdose. Gastrointestinal decontamination, (e.g. gastric lavage followed by activated charcoal) should be considered in patients suspected of an overdose with Rizaltriptan Orodispersible Tablets. Clinical and electrocardiographic monitoring should be continued for at least 12 hours, even if clinical symptoms are not observed.

The effects of haemo- or peritoneal dialysis on serum concentrations of Rizaltriptan are unknown.

Pharmacotherapeutic group: analgesics; antimigraine preparations; selective serotonin (5HT 1) agonists, ATC-code: N02C C04

Mechanism of Action: Selective serotonin (5HT_1B/1D) agonists

Rizaltriptan binds selectively with high affinity to human 5-HT_1B and 5-HT_1D receptors and has little or no effect or pharmacological activity at 5-HT₂, 5-HT₃; adrenergic alpha₁, alpha₂ or beta; D₁, D₂, dopaminergic, histaminic H₁; muscarinic; or benzodiazepine receptors.

The therapeutic activity of Rizaltriptan in treating migraine headache may be attributed to its agonist effects at 5-HT_1B and 5-HT_1D receptors on the extracerebral intracranial blood vessels that are thought to become dilated during an attack and on the trigeminal sensory nerves that innervate them. Activation of these 5-HT_1B and 5-HT_1D receptors may result in constriction of pain-producing intracranial blood vessels and inhibition of neuropeptide release that leads to decreased inflammation in sensitive tissues and reduced central trigeminal pain signal transmission.

Clinical efficacy and safety

Adults

Tablets

The efficacy of Rizaltriptan tablets in the acute treatment of migraine attacks was established in four multicentre, placebo-controlled trials that included over 2,000 patients who received Rizaltriptan 5 or 10 mg for up to one year. Headache relief occurred as early as 30 minutes following dosing, and response rates, (i.e. reduction of moderate or severe headache pain to no or mild pain) two hours after treatment were 67-77% with the 10 mg tablet, 60-63% with the 5 mg tablet, and 23-40% with placebo. Although patients who did not respond to initial treatment with Rizaltriptan tablets were not redosed for the same attack, they were still likely to respond to treatment for a subsequent attack. Rizaltriptan reduced the functional disability and relieved the nausea, photophobia, and phonophobia associated with migraine attacks.

Rizaltriptan remains effective in treating menstrual migraine, i.e. migraine that occurs within 3 days before or after the onset of menses.

Orodispersible tablets

The efficacy of a Rizaltriptan orodispersible tablet in the acute treatment of migraine attacks was established in two multicentre, randomised, placebo-controlled trials that were similar in design to the trials of Rizaltriptan tablets. In one study (n=311), by two hours post-dosing, relief rates in patients treated with Rizaltriptan orodispersible tablets were approximately 66% for Rizaltriptan 5 mg and 10 mg, compared to 47% in the placebo group. In a larger study (n=547), by two hours post-dosing, relief rates were 59% in patients treated with a Rizaltriptan orodispersible tablet 5 mg, and 74% after 10 mg, compared to 28% in the placebo group. A Rizaltriptan orodispersible tablets also relieved the disability, nausea, photophobia, and phonophobia which accompanied the migraine episodes. A significant effect on pain relief was observed as early as 30 minutes post-dosing in one of the two clinical trials for the 10 mg dose.

Based on studies with the oral tablet, Rizaltriptan remains effective in treating menstrual migraine, i.e. migraine that occurs within 3 days before or after the onset of menses.

Paediatric population

Adolescents (12-17 years of age)

The efficacy of Rizaltriptan in paediatric patients (12 to 17 years of age) was evaluated in a multicenter, randomised, double-blind, placebo-controlled, parallel group study (n=570). The patient population was required to be historically non-responsive to NSAIDs and acetaminophen therapy. Patients with a qualifying migraine headache initially administered placebo or Rizaltriptan within 30 minutes of onset. Following the 15 minute placebo run-in, subjects who did not respond to placebo then treated a single migraine attack with placebo or Rizaltriptan. Using a weight-based dosing strategy, patients 20 kg to <40 kg received 5 mg Rizaltriptan and patients 40 kg received 10 mg Rizaltriptan.

In this enriched population study, a difference of 9% between active treatment and placebo was observed for the primary efficacy endpoint of pain freedom (reduction from moderate or severe pain to no pain) 2 hours after treatment (31% under Rizaltriptan vs. 22% for placebo (p=0.025)). No significant difference for the secondary endpoint of pain relief (reduction from moderate or severe pain to mild or no pain) was found.

Children (6-11 years of age)

The efficacy of Rizaltriptan was also evaluated in paediatric patients 6 to 11 years of age in the same acute placebo-controlled clinical trial (n=200). The percentage of patients achieving pain freedom 2 hours after treatment was not statistically significantly different in patients who received Rizaltriptan 5 and 10 mg, compared with those who received placebo (39.8% vs. 30.4%, p=0.269).

Rizaltriptan Orodispersible Tablets enable migraine patients to treat their migraine attacks without having to swallow liquids. This may allow patients to administer their medication earlier, for example, when liquids are not available, and to avoid possible worsening of GI symptoms by swallowing liquids.

Absorption

Rizaltriptan is rapidly and completely absorbed following oral administration.

Tablets: The mean oral bioavailability of the tablet is approximately 40-45%, and mean peak plasma concentrations (C_max) are reached in approximately 1-1.5 hours (T_max). Administration of an oral tablet dose with a high-fat breakfast had no effect on the extent of Rizaltriptan absorption, but absorption was delayed for approximately one hour.

Orodispersible tablets: The mean oral bioavailability of the oro- dispersible tablet is approximately 40-45%, and mean peak plasma concentrations (C_max) are reached in approximately 1.58 hours (T_max).

The time to maximum plasma concentration following administration of Rizaltriptan as the oro- dispersible tablet formulation is delayed by 30-60 minutes relative to the tablet.

Effect of food: The effect of food on the absorption of Rizaltriptan from the orodispersible tablet has not been studied. For the Rizaltriptan tablets, Tmax is delayed by approximately 1 hour when the tablets are administered in the fed state. A further delay in the absorption of Rizaltriptan may occur when the orodispersible tablet is administered after meals..

Distribution

Rizaltriptan is minimally bound (14%) to plasma proteins. The volume of distribution is approximately 140 litres in male subjects, and 110 litres in female subjects.

Biotransformation

The primary route of Rizaltriptan metabolism is via oxidative deamination by monoamine oxidase-A (MAO-A) to the indole acetic acid metabolite, which is not pharmacologically active. N-monodesmethyl-Rizaltriptan, a metabolite with activity similar to that of parent compound at the 5-HT_1B/1D receptors, is formed to a minor degree, but does not contribute significantly to the pharmacodynamic activity of Rizaltriptan. Plasma concentrations of N-monodesmethyl-Rizaltriptan are approximately 14% of those of parent compound, and it is eliminated at a similar rate. Other minor metabolites include the N-oxide, the 6-hydroxy compound, and the sulphate conjugate of the 6-hydroxy metabolite. None of these minor metabolites is pharmacologically active. Following oral administration of ¹⁴C-labelled Rizaltriptan, Rizaltriptan accounts for about 17% of circulating plasma radioactivity.

Elimination

Following intravenous administration, AUC in men increases proportionally and in women near-proportionally with the dose over a dose range of 10-60 µg/kg. Following oral administration, AUC increases near-proportionally with the dose over a dose range of 2.5-10 mg. The plasma half-life of Rizaltriptan in males and females averages 2-3 hours. The plasma clearance of Rizaltriptan averages about 1,000-1,500 ml/min in males and about 900-1,100 ml/min in females; about 20-30% of this is renal clearance. Following an oral dose of ¹⁴C-labelled Rizaltriptan, about 80% of the radioactivity is excreted in urine, and about 10% of the dose is excreted in faeces. This shows that the metabolites are excreted primarily via the kidneys.

Consistent with its first pass metabolism, approximately 14% of an oral dose is excreted in urine as unchanged Rizaltriptan while 51% is excreted as indole acetic acid metabolite. No more than 1% is excreted in urine as the active N-monodesmethyl metabolite.

If Rizaltriptan is administered according to the maximum dosage regimen, no drug accumulation in the plasma occurs from day to day.

Characteristics in patients

The following data are based on studies with the oral tablet formulation.

Patients with a migraine attack: A migraine attack does not affect the pharmacokinetics of Rizaltriptan.

Gender: The AUC of Rizaltriptan (10 mg orally) was about 25% lower in males as compared to females, C_max was 11% lower, and T_max occurred at approximately the same time. This apparent pharmacokinetic difference was of no clinical significance.

Older people: The plasma concentrations of Rizaltriptan observed in older subjects (age range 65 to 77 years) after tablet administration were similar to those observed in young adults.

Paediatric: A pharmacokinetics study of Rizaltriptan (as the oral lyophilisates formulation) was conducted in paediatric migraineurs 6 to 17 years of age. The mean exposures following a single dose administration of 5 mg Rizaltriptan oral lyophilisates to paediatric patients weighing 20-39 kg or 10 mg Rizaltriptan oral lyophilisates to paediatric patients weighing 40 kg were respectively 15% lower and 17% higher compared to the exposure observed following single dose administration of 10 mg Rizaltriptan oral lyophilisates to adults. The clinical relevance of these differences is unclear.

Hepatic impairment (Child-Pugh's score 5-6): Following oral tablet administration in patients with hepatic impairment caused by mild alcoholic cirrhosis of the liver, plasma concentrations of Rizaltriptan were similar to those seen in young male and female subjects. A significant increase in AUC (50%) and C_max (25%) was observed in patients with moderate hepatic impairment (Child-Pugh's score 7). Pharmacokinetics were not studied in patients with Child-Pugh's score >7 (severe hepatic impairment).

Renal impairment: In patients with renal impairment (creatinine clearance 10 - 60 ml/min/1.73 m²), the AUC of Rizaltriptan after tablet administration was not significantly different from that in healthy subjects. In haemodialysis patients (creatinine clearance <10 ml/min/1.73 m²), the AUC for Rizaltriptan was approximately 44% greater than that in patients with normal renal function. The maximal plasma concentration of Rizaltriptan in patients with all degrees of renal impairment was similar to that in healthy subjects.

Non-clinical data reveal no special hazard for humans based on conventional studies of safety pharmacology, repeated dose toxicity, genotoxicity, carcinogenic potential, toxicity to reproduction and development, and pharmacokinetics and metabolism.

Not applicable.

No special requirements for disposal.

Any unused medicinal product or waste material should be disposed of in accordance with local requirements.