Rizatriptan Benzoate

The recommended starting dose of rizatriptan benzoate orally disintegrating tablets is either 5 mg or 10 mg for the acute treatment of migraines in adults. The 10 mg dose may provide a greater effect than the 5 mg dose, but may have a greater risk of adverse reactions [see Clinical Studies (14.1)].

Redosing in Adults
Although the effectiveness of a second dose or subsequent doses has not been established in placebo-controlled trials, if the migraine headache returns, a second dose may be administered 2 hours after the first dose. The maximum daily dose should not exceed 30 mg in any 24-hour period. The safety of treating, on average, more than four headaches in a 30-day period has not been established.

Dosing in pediatric patients is based on the patient's body weight. The recommended dose of rizatriptan benzoate orally disintegrating tablets is 5 mg in patients weighing less than 40 kg (88 lb), and 10 mg in patients weighing 40 kg (88 lb) or more.

The efficacy and safety of treatment with more than one dose of rizatriptan benzoate orally disintegrating tablets within 24 hours in pediatric patients 6 to 17 years of age have not been established.

For rizatriptan benzoate orally disintegrating tablets, administration with liquid is not necessary.  Orally disintegrating tablets are packaged in a blister within an outer aluminum pouch and patients should not remove the blister from the outer pouch until just prior to dosing.  The blister pack should then be peeled open with dry hands and the orally disintegrating tablet placed on the tongue, where it will dissolve and be swallowed with the saliva.

Adult Patients
In adult patients taking propranolol, only the 5 mg dose of rizatriptan benzoate orally disintegrating tablets is recommended, up to a maximum of 3 doses in any 24-hour period (15 mg) [see Drug Interactions (7.1) and Clinical Pharmacology (12.3)].

Pediatric Patients
For pediatric patients weighing ≥40 kg (88 lb) taking propranolol, only a single 5 mg dose of rizatriptan benzoate orally disintegrating tablets is recommended (maximum dose of 5 mg in a 24-hour period). Rizatriptan benzoate orally disintegrating tablets should not be prescribed to propranolol-treated pediatric patients who weigh less than 40 kg (88 lb) [see Drug Interactions (7.1) and Clinical Pharmacology (12.3)]. 

Rizatriptan benzoate should not be given to patients with ischemic or vasospastic coronary artery disease. There have been rare reports of serious cardiac adverse reactions, including acute myocardial infarction, occurring within a few hours following administration of rizatriptan benzoate. Some of these reactions occurred in patients without known coronary artery disease (CAD). 5-HT₁ agonists including rizatriptan benzoate may cause coronary artery vasospasm (Prinzmetal's Angina), even in patients without a history of CAD.

Triptan-naïve patients who have multiple cardiovascular risk factors (e.g., increased age, diabetes, hypertension, smoking, obesity, strong family history of CAD) should have a cardiovascular evaluation prior to receiving rizatriptan benzoate. If there is evidence of CAD or coronary artery vasospasm, rizatriptan benzoate should not be administered [see Contraindications (4)] . For patients who have a negative cardiovascular evaluation, consideration should be given to administration of the first rizatriptan benzoate dose in a medically-supervised setting and performing an electrocardiogram (ECG) immediately following rizatriptan benzoate administration. Periodic cardiovascular evaluation should be considered in intermittent long-term users of rizatriptan benzoate who have cardiovascular risk factors.

Life-threatening disturbances of cardiac rhythm, including ventricular tachycardia and ventricular fibrillation leading to death, have been reported within a few hours following the administration of 5-HT₁ agonists. Discontinue rizatriptan benzoate if these disturbances occur.

As with other 5-HT₁ agonists, sensations of tightness, pain, pressure, and heaviness in the precordium, throat, neck and jaw commonly occur after treatment with rizatriptan benzoate and are usually non-cardiac in origin. However, if a cardiac origin is suspected, patients should be evaluated. Patients shown to have CAD and those with Prinzmetal's variant angina should not receive 5-HT₁ agonists.

Cerebral hemorrhage, subarachnoid hemorrhage, and stroke have occurred in patients treated with 5-HT₁ agonists, and some have resulted in fatalities. In a number of cases, it appears possible that the cerebrovascular events were primary, the 5-HT₁ agonist having been administered in the incorrect belief that the symptoms experienced were a consequence of migraine, when they were not. Also, patients with migraine may be at increased risk of certain cerebrovascular events (e.g., stroke, hemorrhage, transient ischemic attack). Discontinue rizatriptan benzoate if a cerebrovascular event occurs.

As with other acute migraine therapies, before treating headaches in patients not previously diagnosed as migraineurs, and in migraineurs who present with atypical symptoms, care should be taken to exclude other potentially serious neurological conditions. Rizatriptan benzoate should not be administered to patients with a history of stroke or transient ischemic attack [see Contraindications (4)] .

5-HT₁ agonists, including rizatriptan benzoate, may cause non-coronary vasospastic reactions, such as peripheral vascular ischemia, gastrointestinal vascular ischemia and infarction (presenting with abdominal pain and bloody diarrhea), splenic infarction, and Raynaud’s syndrome. In patients who experience symptoms or signs suggestive of non-coronary vasospasm reaction following the use of any 5-HT₁ agonist, the suspected vasospasm reaction should be ruled out before receiving additional rizatriptan benzoate doses. 

Reports of transient and permanent blindness and significant partial vision loss have been reported with the use of 5-HT₁ agonists. Since visual disorders may be part of a migraine attack, a causal relationship between these events and the use of 5-HT₁ agonists have not been clearly established.

Overuse of acute migraine drugs (e.g., ergotamine, triptans, opioids, or a combination of drugs for 10 or more days per month) may lead to exacerbation of headache (medication overuse headache). Medication overuse headache may present as migraine-like daily headaches, or as a marked increase in frequency of migraine attacks. Detoxification of patients, including withdrawal of the overused drugs, and treatment of withdrawal symptoms (which often includes a transient worsening of headache) may be necessary.

Serotonin syndrome may occur with triptans, including rizatriptan benzoate particularly during co-administration with selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), and MAO inhibitors [see Drug Interactions (7.5)]. Serotonin syndrome symptoms may include mental status changes (e.g., agitation, hallucinations, coma), autonomic instability (e.g., tachycardia, labile blood pressure, hyperthermia), neuromuscular aberrations (e.g., hyperreflexia, incoordination) and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea). The onset of symptoms can occur within minutes to hours of receiving a new or a greater dose of a serotonergic medication. Rizatriptan benzoate treatment should be discontinued if serotonin syndrome is suspected [see Drug Interactions (7.4) and Patient Counseling Information (17)].

Significant elevation in blood pressure, including hypertensive crisis with acute impairment of organ systems, has been reported on rare occasions in patients with and without a history of hypertension receiving 5-HT₁ agonists, including rizatriptan benzoate. In healthy young adult male and female patients who received maximal doses of rizatriptan benzoate (10 mg every 2 hours for 3 doses), slight increases in blood pressure (approximately 2-3 mmHg) were observed. Rizatriptan benzoate is contraindicated in patients with uncontrolled hypertension [see Contraindications (4)].

Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice.

Adults

Incidence in Controlled Clinical Trials
Adverse reactions to rizatriptan benzoate were assessed in controlled clinical trials that included over 3700 adult patients who received single or multiple doses of rizatriptan benzoate tablets. The most common adverse reactions during treatment with rizatriptan benzoate (≥ 5% in either treatment group and greater than placebo) were asthenia/fatigue, somnolence, pain/pressure sensation and dizziness. These adverse reactions appeared to be dose related.

Table 1 lists the adverse reactions (incidence ≥ 2% and greater than placebo) after a single dose of rizatriptan benzoate in adults.

Table 1:  Incidence (≥2% and Greater than Placebo) of Adverse Reactions After a Single Dose of Rizatriptan Benzoate Tablets or Placebo in Adults

The frequencies of adverse reactions in clinical trials did not increase when up to three doses were taken within 24 hours. Adverse reaction frequencies were also unchanged by concomitant use of drugs commonly taken for migraine prophylaxis (including propranolol), oral contraceptives, or analgesics. The incidences of adverse reactions were not affected by age or gender. There were insufficient data to assess the impact of race on the incidence of adverse reactions.

Other Events Observed in Association with the Administration of Rizatriptan Benzoate in Adults
In the following section, the frequencies of less commonly reported adverse events are presented that were not reported in other sections of the labeling. Because the reports include events observed in open studies, the role of rizatriptan benzoate in their causation cannot be reliably determined. Furthermore, variability associated with adverse event reporting, the terminology used to describe adverse events, limit the value of the quantitative frequency estimates provided. Event frequencies are calculated as the number of patients who used rizatriptan benzoate and reported an event divided by the total number of patients exposed to rizatriptan benzoate (N = 3716). All reported events occurred at an incidence ≥ 1%, or are believed to be reasonably associated with the use of the drug. Events are further classified within body system categories and enumerated in order of decreasing frequency using the following definitions: frequent adverse events are those defined as those occurring in at least (>) 1/100 patients; infrequent adverse experiences are those occurring in 1/100 to 1/1000 patients; and rare adverse experiences are those occurring in fewer than 1/1000 patients.

General: Infrequent was facial edema. Rare were syncope and edema/swelling. 

Atypical Sensations: Frequent were warm sensations. 

Cardiovascular: Frequent was palpitation. Infrequent were tachycardia, cold extremities, and bradycardia. 

Digestive: Frequent were diarrhea and vomiting. Infrequent were dyspepsia, tongue edema and abdominal distention. 

Musculoskeletal: Infrequent were muscle weakness, stiffness, myalgia and muscle cramp/spasm.

Neurological/Psychiatric: Frequent were hypoesthesia, euphoria and tremor. Infrequent were vertigo, insomnia, confusion/disorientation, gait abnormality, memory impairment, and agitation.

Respiratory: Frequent was dyspnea. Infrequent was pharyngeal edema. 

Special Senses: Infrequent were blurred vision and tinnitus. Rare was eye swelling.

Skin and Skin Appendage: Frequent was flushing. Infrequent were sweating, pruritus, rash, and urticaria. Rare was erythema, hot flashes.

The adverse reaction profile seen with rizatriptan benzoate orally disintegrating tablets was similar to that seen with rizatriptan benzoate tablets. 

Pediatric Patients 6 to 17 Years of Age

Incidence in Controlled Clinical Trials in Pediatric Patients
Adverse reactions to rizatriptan benzoate orally disintegrating tablets were assessed in a controlled clinical trial in the acute treatment of migraines (Study 7) that included a total of 1382 pediatric patients 6-17 years of age, of which 977 (72%) administered at least one dose of study treatment (rizatriptan benzoate orally disintegrating tablets and/or placebo) [see Clinical Studies (14.2)]. The incidence of adverse reactions reported for pediatric patients in the acute clinical trial was similar in patients who received rizatriptan benzoate to those who received placebo. The adverse reaction pattern in pediatric patients is expected to be similar to that in adults.

Other Events Observed in Association with the Administration of Rizatriptan Benzoate Orally Disintegrating Tablets in Pediatric Patients
In the following section, the frequencies of less commonly reported adverse events are presented. Because the reports include events observed in open studies, the role of rizatriptan benzoate orally disintegrating tablets in their causation cannot be reliably determined. Furthermore, variability associated with adverse event reporting, the terminology used to describe adverse events, limit the value of the quantitative frequency estimates provided.

Event frequencies are calculated as the number of pediatric patients 6 to 17 years of age who used rizatriptan benzoate orally disintegrating tablets and reported an event divided by the total number of patients exposed to rizatriptan benzoate orally disintegrating tablets (N=1068). All reported events occurred at an incidence ≥1%, or are believed to be reasonably associated with the use of the drug. Events are further classified within system organ class and enumerated in order of decreasing frequency using the following definitions: frequent adverse events are those occurring in (>)1/100 pediatric patients; infrequent adverse experiences are those occurring in 1/100 to 1/1000 pediatric patients; and rare adverse experiences are those occurring in fewer than 1/1000 patients.

General: Frequent was fatigue.

Ear and labyrinth disorders: Infrequent was hypoacusis.

Gastrointestinal disorders: Frequent was abdominal discomfort.

Nervous system disorders: Infrequent were coordination abnormal, disturbance in attention, and presyncope.

Psychiatric disorders: Infrequent was hallucination.

The following section enumerates potentially important adverse events that have occurred in clinical practice and which have been reported spontaneously to various surveillance systems. The events enumerated include all except those already listed in other sections of the labeling or those too general to be informative. Because the reports cite events reported spontaneously from worldwide postmarketing experience, frequency of events and the role of rizatriptan benzoate in their causation cannot be reliably determined. 

Neurological/Psychiatric: Seizure. 

General: Allergic conditions including anaphylaxis/anaphylactoid reaction, angioedema, wheezing, and toxic epidermal necrolysis [see Contraindications (4)]. 

Special Senses: Dysgeusia.

The dose of rizatriptan benzoate should be adjusted in propranolol-treated patients, as propranolol has been shown to increase the plasma AUC of rizatriptan by 70% [see Dosage and Administration (2.4) and Clinical Pharmacology (12.3)].

Ergot-containing drugs have been reported to cause prolonged vasospastic reactions. Because these effects may be additive, use of ergotamine-containing or ergot-type medications (like dihydroergotamine or methysergide) and rizatriptan benzoate within 24 hours is contraindicated [see Contraindications (4)].

Because their vasospastic effects may be additive, co-administration of rizatriptan benzoate and other 5-HT₁ agonists within 24 hours of each other is contraindicated [see Contraindications (4)].

Cases of serotonin syndrome have been reported during co-administration of triptans and selective serotonin reuptake inhibitors (SSRIs) or serotonin norepinephrine reuptake inhibitors (SNRIs) [see Warnings and Precautions (5.7)].

Rizatriptan benzoate is contraindicated in patients taking MAO-A inhibitors and non-selective MAO inhibitors. A specific MAO-A inhibitor increased the systemic exposure of rizatriptan and its metabolite [see Contraindications (4) and Clinical Pharmacology (12.3)].

Pregnancy Category C 
There are no adequate and well-controlled studies in pregnant women. Rizatriptan benzoate should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

In a general reproductive study in rats, birth weights and pre- and post-weaning weight gain were reduced in the offspring of females treated prior to and during mating and throughout gestation and lactation with doses of 10 and 100 mg/kg/day. In a pre- and post-natal developmental toxicity study in rats, an increase in mortality of the offspring at birth and for the first three days after birth, a decrease in pre- and post-weaning weight gain, and decreased performance in a passive avoidance test (which indicates a decrease in learning capacity of the offspring) were observed at doses of 100 and 250 mg/kg/day. The no-effect dose for all of these effects was 5 mg/kg/day, associated with a maternal plasma exposure (AUC) approximately 7.5 times that in humans receiving the MRDD. With doses of 100 and 250 mg/kg/day, the decreases in average weight of both the male and female offspring persisted into adulthood. All effects on the offspring in both studies occurred in the absence of any apparent maternal toxicity. 

In embryofetal development studies, no teratogenic effects were observed when pregnant rats and rabbits were administered doses of 100 and 50 mg/kg/day, respectively, during organogenesis. Fetal weights were decreased in conjunction with decreased maternal weight gain at the highest doses tested. The developmental no-effect dose in these studies was 10 mg/kg/day in both rats and rabbits (maternal exposures approximately 15 times human exposure at the MRDD). Toxicokinetic studies demonstrated placental transfer of drug in both species.

It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when rizatriptan benzoate is administered to a nursing woman. Rizatriptan is extensively excreted in rat milk, with levels in milk at least 5-fold higher than levels in maternal plasma.

Safety and effectiveness in pediatric patients under 6 years of age have not been established. 

The efficacy and safety of rizatriptan benzoate in the acute treatment of migraine in patients aged 6 to 17 years was established in an adequate and well-controlled study [see Clinical Studies (14.2)].

The incidence of adverse reactions reported for pediatric patients in the acute clinical trial was similar in patients who received rizatriptan benzoate to those who received placebo. The adverse reaction pattern in pediatric patients is expected to be similar to that in adults.

Clinical studies of rizatriptan benzoate did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.  

Although the pharmacokinetics of rizatriptan were similar in elderly (aged ≥ 65 years) and in younger adults (n=17), in general, dose selection for an elderly patient should be cautious, starting at the low end of the dosing range. This reflects the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. 

Geriatric patients who have other cardiovascular risk factors (e.g., diabetes, hypertension, smoking, obesity, strong family history of coronary artery disease) should have a cardiovascular evaluation prior to receiving rizatriptan benzoate [see Warnings and Precautions (5.1)].

Rizatriptan binds with high affinity to human cloned 5-HT_1B/1D receptors. Rizatriptan presumably exerts its therapeutic effects in the treatment of migraine headache by binding to 5-HT_1B/1D receptors located on intracranial blood vessels and sensory nerves of the trigeminal system.

Absorption 
Rizatriptan is completely absorbed following oral administration. The mean oral absolute bioavailability of the rizatriptan benzoate tablets is about 45%, and mean peak plasma concentrations (C_max) are reached in approximately 1 to 1.5 hours (T_max). The presence of a migraine headache did not appear to affect the absorption or pharmacokinetics of rizatriptan. Food has no significant effect on the bioavailability of rizatriptan but delays the time to reach peak concentration by an hour. In clinical trials, rizatriptan benzoate was administered without regard to food. 

The bioavailability and C_max of rizatriptan were similar following administration of rizatriptan benzoate tablets and rizatriptan benzoate orally disintegrating tablets, but the rate of absorption is somewhat slower with rizatriptan benzoate orally disintegrating tablets, with T_max delayed by up to 0.7 hour. AUC of rizatriptan is approximately 30% higher in females than in males. No accumulation occurred on multiple dosing. 

Distribution
The mean volume of distribution is approximately 140 liters in male subjects and 110 liters in female subjects. Rizatriptan is minimally bound (14%) to plasma proteins. 

Metabolism
The primary route of rizatriptan metabolism is via oxidative deamination by monoamine oxidase-A (MAO-A) to the indole acetic acid metabolite, which is not active at the 5-HT_1B/1D receptor. N-monodesmethyl-rizatriptan, a metabolite with activity similar to that of parent compound at the 5-HT_1B/1D receptor, is formed to a minor degree. Plasma concentrations of N-monodesmethyl-rizatriptan are approximately 14% of those of parent compound, and it is eliminated at a similar rate. Other minor metabolites, the N-oxide, the 6-hydroxy compound, and the sulfate conjugate of the 6-hydroxy metabolite are not active at the 5-HT_1B/1D receptor. 

Elimination 
The total radioactivity of the administered dose recovered over 120 hours in urine and feces was 82% and 12%, respectively, following a single 10 mg oral administration of ¹⁴C-rizatriptan. Following oral administration of ¹⁴C-rizatriptan, rizatriptan accounted for about 17% of circulating plasma radioactivity. Approximately 14% of an oral dose is excreted in urine as unchanged rizatriptan while 51% is excreted as indole acetic acid metabolite, indicating substantial first pass metabolism.

The plasma half-life of rizatriptan in males and females averages 2 to 3 hours.  

Cytochrome P450 Isoforms
Rizatriptan is not an inhibitor of the activities of human liver cytochrome P450 isoforms 3A4/5, 1A2, 2C9, 2C19, or 2E1; rizatriptan is a competitive inhibitor (K_i = 1400 nM) of cytochrome P450 2D6, but only at high, clinically irrelevant concentrations.  

Special Populations
Geriatric: Rizatriptan pharmacokinetics in healthy elderly non-migraineur volunteers (age 65 to 77 years) were similar to those in younger non-migraineur volunteers (age 18 to 45 years). 

Pediatric: The pharmacokinetics of rizatriptan was determined in pediatric migraineurs 6 to 17 years of age. Exposures following single dose administration of 5 mg rizatriptan benzoate orally disintegrating tablets to pediatric patients weighing 20-39 kg (44-87 lb) or 10 mg rizatriptan benzoate orally disintegrating tablets to pediatric patients weighing ≥40 kg (88 lb) were similar to those observed following single dose administration of 10 mg rizatriptan benzoate orally disintegrating tablets to adults.

Gender: The mean AUC_0-∞ and C_max of rizatriptan (10 mg orally) were about 30% and 11% higher in females as compared to males, respectively, while T_max occurred at approximately the same time. 

Hepatic impairment: Following oral administration in patients with hepatic impairment caused by mild to moderate alcoholic cirrhosis of the liver, plasma concentrations of rizatriptan were similar in patients with mild hepatic insufficiency compared to a control group of subjects with normal hepatic function; plasma concentrations of rizatriptan were approximately 30% greater in patients with moderate hepatic insufficiency.

Renal impairment: In patients with renal impairment (creatinine clearance 10-60 mL/min/1.73 m²), the AUC_0-∞ of rizatriptan was not significantly different from that in subjects with normal renal function. In hemodialysis patients, (creatinine clearance < 2 mL/min/1.73 m²), however, the AUC for rizatriptan was approximately 44% greater than that in patients with normal renal function.

Race: Pharmacokinetic data revealed no significant differences between African American and Caucasian subjects.

Drug Interactions
[See also Drug Interactions (7).] 

Monoamine Oxidase Inhibitors: Rizatriptan is principally metabolized via monoamine oxidase, ‘A’ subtype (MAO-A). Plasma concentrations of rizatriptan may be increased by drugs that are selective MAO-A inhibitors (e.g., moclobemide) or nonselective MAO inhibitors [type A and B] (e.g., isocarboxazid, phenelzine, tranylcypromine, and pargyline). In a drug interaction study, when rizatriptan 10 mg was administered to subjects (n = 12) receiving concomitant therapy with the selective, reversible MAO-A inhibitor, moclobemide 150 mg t.i.d., there were mean increases in rizatriptan AUC and C_max of 119% and 41% respectively; and the AUC of the active N-monodesmethyl metabolite of rizatriptan was increased more than 400%. The interaction would be expected to be greater with irreversible MAO inhibitors. No pharmacokinetic interaction is anticipated in patients receiving selective MAO-B inhibitors [see Contraindications (4) and Drug Interactions (7.5)]. 

Propranolol: In a study of concurrent administration of propranolol 240 mg/day and a single dose of rizatriptan 10 mg in healthy adult subjects (n = 11), mean plasma AUC for rizatriptan was increased by 70% during propranolol administration, and a four-fold increase was observed in one subject. The AUC of the active N-monodesmethyl metabolite of rizatriptan was not affected by propranolol [see Dosage and Administration (2.4) and Drug Interactions (7.1)]. 

Nadolol/Metoprolol: In a drug interactions study, effects of multiple doses of nadolol 80 mg or metoprolol 100 mg every 12 hours on the pharmacokinetics of a single dose of 10 mg rizatriptan were evaluated in healthy subjects (n = 12). No pharmacokinetic interactions were observed.

Paroxetine: In a study of the interaction between the selective serotonin reuptake inhibitor (SSRI) paroxetine 20 mg/day for two weeks and a single dose of rizatriptan 10 mg in healthy subjects (n = 12), neither the plasma concentrations of rizatriptan nor its safety profile were affected by paroxetine [see Warnings and Precautions (5.7), Drug Interactions (7.4), and Patient Counseling Information (17)].

Oral contraceptives: In a study of concurrent administration of an oral contraceptive during 6 days of administration of rizatriptan (10 to 30 mg/day) in healthy female volunteers (n=18), rizatriptan did not affect plasma concentrations of ethinyl estradiol or norethindrone.

Carcinogenesis: Oral carcinogenicity studies were conducted in mice (100 weeks) and rats (106 weeks) at doses of up to 125 mg/kg/day. Plasma exposures (AUC) at the highest dose tested were approximately 150 (mice) and 240 times (rats) that in humans at the maximum recommended daily dose (MRDD) of 30 mg/day. There was no evidence of an increase in tumor incidence related to rizatriptan in either species. 

Mutagenesis: Rizatriptan was neither mutagenic nor clastogenic in a battery of in vitro and in vivo genetic toxicity studies, including: the microbial mutagenesis (Ames) assay, in vitro mammalian cell mutagenesis and chromosomal aberration assays, and the in vivo chromosomal aberration assay in mouse. 

Impairment of Fertility: In a fertility study in rats, altered estrus cyclicity and delays in time to mating were observed in females treated orally with 100 mg/kg/day rizatriptan. The no-effect dose was 10 mg/kg/day (approximately 15 times the human exposure at the MRDD). There were no other fertility-related effects in the female rats. There was no impairment of fertility or reproductive performance in male rats treated with up to 250 mg/kg/day (approximately 550 times the human exposure at the MRDD).

The efficacy of rizatriptan benzoate tablets was established in four multicenter, randomized, placebo-controlled trials. Patients enrolled in these studies were primarily female (84%) and Caucasian (88%), with a mean age of 40 years (range of 18 to 71). Patients were instructed to treat a moderate to severe headache. Headache response, defined as a reduction of moderate or severe headache pain to no or mild headache pain, was assessed for up to 2 hours (Study 1) or up to 4 hours after dosing (Studies 2, 3 and 4). Associated symptoms of nausea, photophobia, and phonophobia and maintenance of response up to 24 hours post-dose were evaluated. A second dose of rizatriptan benzoate tablets was allowed 2 to 24 hours after dosing for treatment of recurrent headache in Studies 1 and 2. Additional analgesics and/or antiemetics were allowed 2 hours after initial treatment for rescue in all four studies.

In all studies, the percentage of patients achieving headache response 2 hours after treatment was significantly greater in patients who received either rizatriptan benzoate 5 or 10 mg compared to those who received placebo. In a separate study, doses of 2.5 mg were not different from placebo. Doses greater than 10 mg were associated with an increased incidence of adverse effects. The results from the four controlled studies are summarized in Table 2.

Table 2: Response Rates 2 Hours Following Treatment of Initial Headache in Studies 1, 2, 3, and 4

^*p-value < 0.05 in comparison with placebo
^†p-value < 0.05 in comparison with 5 mg
^‡Results for initial headache only.

Comparisons of drug performance based upon results obtained in different clinical trials may not be reliable. Because studies are conducted at different times, with different samples of patients, by different investigators, employing different criteria and/or different interpretations of the same criteria, under different conditions (dose, dosing regimen, etc.), quantitative estimates of treatment response and the timing of response may be expected to vary considerably from study to study. 

The estimated probability of achieving an initial headache response within 2 hours following treatment in pooled Studies 1, 2, 3, and 4 is depicted in Figure 1.

Figure 1: Estimated Probability of Achieving an Initial Headache Response by 2 Hours in Pooled Studies 1, 2, 3, and 4^††

^††Figure 1 shows the Kaplan-Meier plot of the probability over time of obtaining headache response (no or mild pain) following treatment with rizatriptan benzoate or placebo. The averages displayed are based on pooled data from 4 placebo-controlled, outpatient trials providing evidence of efficacy (Studies 1, 2, 3, and 4). Patients taking additional treatment or not achieving headache response prior to 2 hours were censored at 2 hours. 

For patients with migraine-associated photophobia, phonophobia, and nausea at baseline, there was a decreased incidence of these symptoms following administration of rizatriptan benzoate compared to placebo. 

Two to 24 hours following the initial dose of study treatment, patients were allowed to use additional treatment for pain response in the form of a second dose of study treatment or other medication. The estimated probability of patients taking a second dose or other medication for migraine over the 24 hours following the initial dose of study treatment is summarized in Figure 2. 

Figure 2: Estimated Probability of Patients Taking a Second Dose of Rizatriptan Benzoate Tablets or Other Medication for Migraines Over the 24 Hours Following the Initial Dose of Study Treatment in Pooled Studies 1, 2, 3, and 4^†††

^†††This Kaplan-Meier plot is based on data obtained in 4 placebo-controlled outpatient clinical trials (Studies 1, 2, 3, and 4). Patients not using additional treatments were censored at 24 hours. The plot includes both patients who had headache response at 2 hours and those who had no response to the initial dose. Remedication was not allowed within 2 hours post-dose. 

Efficacy was unaffected by the presence of aura; by the gender, or age of the patient; or by concomitant use of common migraine prophylactic drugs (e.g., beta-blockers, calcium channel blockers, tricyclic antidepressants) or oral contraceptives. In two additional similar studies, efficacy was unaffected by relationship to menses. There were insufficient data to assess the impact of race on efficacy.   

Rizatriptan Benzoate Orally Disintegrating Tablets
The efficacy of rizatriptan benzoate orally disintegrating tablets was established in two multicenter, randomized, placebo-controlled trials that were similar in design to the trials of rizatriptan benzoate tablets (Studies 5 and 6).  Patients were instructed to treat a moderate to severe headache.  Patients treated in these studies were primarily female (88%) and Caucasian (95%), with a mean age of 42 years (range 18-72). 

In both studies, the percentage of patients achieving headache response 2 hours after treatment was significantly greater in patients who received either rizatriptan benzoate orally disintegrating tablets 5 or 10 mg compared to those who received placebo. The results from Studies 5 and 6 are summarized in Table 3. 

Table 3: Response Rates 2 Hours Following Treatment of Initial Headache in Studies 5 and 6  

The estimated probability of achieving an initial headache response by 2 hours following treatment with rizatriptan benzoate orally disintegrating tablets in pooled Studies 5 and 6 is depicted in Figure 3. 

Figure 3:  Estimated Probability of Achieving an Initial Headache Response with Rizatriptan Benzoate Orally Disintegrating Tablets by 2 Hours in Pooled Studies 5 and 6^‡

^‡Figure 3 shows the Kaplan-Meier plot of the probability over time of obtaining headache response (no or mild pain) following treatment with rizatriptan benzoate orally disintegrating tablets or placebo. The averages displayed are based on pooled data from 2 placebo-controlled, outpatient trials providing evidence of efficacy (Studies 5 and 6). Patients taking additional treatment or not achieving headache response prior to 2 hours were censored at 2 hours.

For patients with migraine-associated photophobia and phonophobia at baseline, there was a decreased  incidence of these symptoms  following  administration  of  rizatriptan benzoate orally disintegrating tablets as compared  to placebo. 

Two to 24 hours following the initial dose of study treatment, patients were allowed to use additional treatment for pain response in the form of a  second dose of study treatment or other medication. The estimated probability of patients taking a second dose or other medication for migraine over the 24 hours following the initial dose of study treatment is summarized in Figure 4.

Figure 4:  Estimated Probability of Patients Taking a Second Dose of Rizatriptan Benzoate Orally Disintegrating Tablets or Other Medication for Migraines Over the 24 Hours Following the Initial Dose of Study Treatment in Pooled Studies 5 and 6 ^‡‡

^‡‡This Kaplan-Meier plot is based on data obtained in 2 placebo-controlled outpatient clinical trials (Studies 5 and 6). Patients not using additional treatments were censored at 24 hours. The plot includes both patients who had headache response at 2 hours and those who had no response to the initial dose. Remedication was not allowed within 2 hours post-dose.

The efficacy of rizatriptan benzoate orally disintegrating tablets in pediatric patients 6 to 17 years was evaluated in a multicenter, randomized, double-blind, placebo-controlled, parallel group clinical trial (Study 7). Patients had to have at least a 6-month history of migraine attacks (with or without aura) usually lasting 3 hours or more (when untreated). The patient population was historically non-responsive to NSAIDs and acetaminophen therapy.

Patients were instructed to treat a single migraine attack with headache pain of moderate to severe intensity. The treatment phase of the study had two stages. Stage 1 was used to identify placebo non-responders, who then entered into Stage 2, in which patients were randomized to rizatriptan benzoate orally disintegrating tablets or placebo. Using a weight-based dosing strategy, patients 20 kg to <40 kg (44 lb to <88 lb) received rizatriptan benzoate orally disintegrating tablets 5 mg or placebo, and patients ≥40 kg (88 lb) received rizatriptan benzoate orally disintegrating tablets 10 mg or placebo.

The mean age for the studied patient population was 13 years. Sixty-one percent of the patients were Caucasian, and fifty-six percent of the patients were female. The percentage of patients achieving the primary efficacy endpoint of no headache pain at 2 hours after treatment was significantly greater in patients who received rizatriptan benzoate orally disintegrating tablets, compared with those who received placebo (33% vs. 24%). Study 7 results are summarized in Table 4.

Table 4: Response Rates 2 Hours Following Treatment of Initial Headache in Pediatric Patients 6 to 17 Years of Age in Study 7

n = Number of evaluable patients with no headache pain at 2 hours post-dose.
m = Number of evaluable patients in population

The observed percentage of pediatric patients achieving no headache pain within 2 hours following initial treatment with rizatriptan benzoate orally disintegrating tablets is shown in Figure 5.

Figure 5: Observed Percentage of Patients Reporting No Headache Pain by 2 Hours Post-Dose in Study 7

The prevalence of the exploratory endpoints of absence of migraine-associated symptoms (nausea, photophobia, and phonophobia) at 2 hours after taking the dose was not statistically significantly different between patients who received rizatriptan benzoate orally disintegrating tablets and those who received placebo.