Frovatriptan Succinate

Frovatriptan succinate tablets are contraindicated in patients with ischemic or vasospastic CAD. There have been rare reports of serious cardiac adverse reactions, including acute myocardial infarction, occurring within a few hours following administration of frovatriptan succinate tablets. Some of these reactions occurred in patients without known CAD. Frovatriptan succinate tablets may cause coronary artery vasospasm (Prinzmetal’s angina), even in patients without a history of CAD.

Perform a cardiovascular evaluation in triptan-naïve patients who have multiple cardiovascular risk factors (e.g., increased age, diabetes, hypertension, smoking, obesity, strong family history of CAD) prior to receiving frovatriptan succinate tablets.  Do not administer frovatriptan succinate tablets if there is evidence of CAD or coronary artery vasospasm [see Contraindications (4)]. For patients with multiple cardiovascular risk factors who have a negative cardiovascular evaluation, consider administrating the first frovatriptan succinate tablets dose in a medically-supervised setting and performing an electrocardiogram (ECG) immediately following frovatriptan succinate tablets administration.  For such patients, consider periodic cardiovascular evaluation in intermittent long-term users of frovatriptan succinate tablets.

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 frovatriptan succinate tablets if these disturbances occur.  Frovatriptan succinate tablets are contraindicated in patients with Wolff-Parkinson-White syndrome or arrhythmias associated with other cardiac accessory conduction pathway disorders [see Contraindications (4)].

Sensations of pain, tightness, pressure, and heaviness have been reported in the chest, throat, neck, and jaw after treatment with frovatriptan succinate tablets and are usually non-cardiac in origin.  However, perform a cardiac evaluation if these patients are at high cardiac risk.  The use of frovatriptan succinate tablets is contraindicated in patients with CAD and those with Prinzmetal’s angina [see Contraindications (4)].

Cerebral hemorrhage, subarachnoid hemorrhage, stroke, and other cerebrovascular events have been reported 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 agonist having been administered in the incorrect belief that the symptoms experienced were a consequence of migraine, when they were not.

Before treating headaches in patients not previously diagnosed as migraineurs, and in migraineurs who present with symptoms atypical of migraine, other potentially serious neurological conditions need to be excluded. Frovatriptan succinate tablets are contraindicated in patients with a history of stroke or TIA [see Contraindications (4)].

Frovatriptan succinate tablets 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 a vasospastic reaction following the use of any 5-HT₁ agonist, rule out a vasospastic reaction before using frovatriptan succinate tablets [see Contraindications (4)].

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 combination of these 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 frovatriptan succinate tablets, particularly during co-administration with selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), and monoamine oxidase (MAO) inhibitors [see Drug Interactions (7.3)]. 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 usually occurs within minutes to hours of receiving a new or a greater dose of a serotonergic medication. Discontinue frovatriptan succinate tablets if serotonin syndrome is suspected.

Significant elevation in blood pressure, including hypertensive crisis with acute impairment of organ systems, has been reported on rare occasions in patients treated with 5-HT₁ agonists, including patients without a history of hypertension.  Monitor blood pressure in patients treated with frovatriptan succinate tablets.  Frovatriptan succinate tablets are contraindicated in patients with uncontrolled hypertension [see Contraindications (4)].

There have been reports of reactions, including anaphylaxis and angioedema, in patients receiving frovatriptan succinate tablets. Such reactions can be life threatening or fatal.  In general, anaphylactic reactions to drugs are more likely to occur in individuals with a history of sensitivity to multiple allergens.  Frovatriptan succinate tablets are contraindicated in patients with a history of hypersensitivity reaction to frovatriptan succinate tablets [see Contraindications (4)].

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

Frovatriptan succinate tablets were evaluated in four randomized, double-blind, placebo-controlled, short-term trials. These trials involved 2392 patients (1554 on frovatriptan succinate tablets 2.5 mg and 838 on placebo). In these short-term trials, patients were predominately female (88%) and Caucasian (94%) with a mean age of 42 years (range 18 to 69).The treatment-emergent adverse events that occurred most frequently following administration of frovatriptan succinate tablets 2.5 mg (i.e., in at least 2% of patients), and at an incidence ≥1% greater than with placebo, were dizziness, paresthesia, headache, dry mouth, fatigue, flushing, hot or cold sensation, dyspepsia, skeletal pain, and chest pain. In a long-term, open-label study where 496 patients were allowed to treat multiple migraine attacks with frovatriptan succinate tablets 2.5 mg for up to 1 year, 5% of patients (n=26) discontinued due to treatment-emergent adverse events.

Table 1 lists treatment-emergent adverse events reported within 48 hours of drug administration that occurred with frovatriptan succinate tablets 2.5 mg at an incidence of ≥2% and more often than on placebo, in the four placebo-controlled trials. The events cited reflect experience gained under closely monitored conditions of clinical trials in a highly selected patient population. In actual clinical practice or in other clinical trials, these incidence estimates may not apply, as the conditions of use, reporting behavior, and the kinds of patients treated may differ.

The incidence of adverse events in clinical trials did not increase when up to 3 doses were used within 24 hours. The incidence of adverse events in placebo-controlled clinical trials was not affected by gender, age, or concomitant medications commonly used by migraine patients. There were insufficient data to assess the impact of race on the incidence of adverse events.

Other Events Observed in Association with the Administration of Frovatriptan Succinate Tablets

The incidence of frequently reported adverse events in four placebo-controlled trials is presented below. Events are further classified within body system categories. Frequent adverse events are those occurring in at least 1/100 patients.

Central and peripheral nervous system: dysesthesia and hypoesthesia.

Gastrointestinal: vomiting, abdominal pain and diarrhea.

Body as a whole: pain.

Psychiatric: insomnia and anxiety.

Respiratory: sinusitis and rhinitis.

Vision disorders: vision abnormal.

Skin and appendages: sweating increased.

Hearing and vestibular disorders: tinnitus.

Heart rate and rhythm: palpitation.

The following adverse reactions were identified during post approval use of frovatriptan succinate tablets. Because these events are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Central and peripheral nervous system:  Seizure.

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 frovatriptan succinate tablets within 24 hours of each other is contraindicated [see Contraindications (4)].

Because their vasospastic effects may be additive, co-administration of frovatriptan succinate tablets and other 5-HT₁ agonists (e.g., triptans) within 24 hours of each other is contraindicated [see Contraindications (4)].

Cases of serotonin syndrome have been reported during combined use of triptans and SSRIs, SNRIs, TCAs, and MAO inhibitors [see Warnings and Precautions (5.7)].

Risk Summary

There are no adequate data on the developmental risk associated with the use of frovatriptan succinate tablets in pregnant women. In animal studies, frovatriptan produced developmental toxicity (embryofetal lethality, fetal abnormalities, and decreased embryofetal growth) when administered to pregnant rats and rabbits at doses greater than those used clinically [see Animal Data].

In the U.S. general population, the estimated background risk of major birth defects and of miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. The reported rate of major birth defects among deliveries to women with migraine ranged from 2.2% to 2.9% and the reported rate of miscarriage was 17%, which were similar to rates reported in women without migraine.

Clinical Considerations

Disease-Associated Maternal and/or Embryo/Fetal Risk

Published data have suggested that women with migraines may be at increased risk of preeclampsia during pregnancy.

Data

Animal Data

When pregnant rats were administered frovatriptan (oral doses of 0, 100, 500, or 1000 mg/kg/day) throughout organogenesis, increased embryofetal mortality and an increased incidence of fetal malformations were observed at the high dose; decreased fetal body weights and increased incidences of fetal structural variations associated with growth impairment were observed at all doses. The lowest effect dose for embryofetal developmental toxicity in rats (100 mg/kg/day) is approximately 130 times the maximum recommended human dose (MRHD) of 7.5 mg/day on a body surface area (mg/m²) basis.

When pregnant rabbits were administered frovatriptan (oral doses of 0, 5, 20, or 80 mg/kg/day) throughout organogenesis, embryofetal mortality was increased at the mid and high doses. The no-effect dose for embryofetal developmental toxicity in rabbits (5 mg/kg/day) is approximately 13 times the MRHD on a mg/m² basis.

Oral administration of frovatriptan (0, 100, 500, or 1000 mg/kg/day) to female rats throughout pregnancy and lactation resulted in increased embryofetal mortality at the high dose. The no effect dose for pre- and postnatal developmental toxicity in rats (500 mg/kg/day) is approximately 650 times the MRHD on a mg/m² basis.

Risk Summary

There are no data on the presence of frovatriptan in human milk, the effects of frovatriptan on the breastfed infant, or the effects of frovatriptan on milk production. In rats, oral dosing with frovatriptan resulted in levels of frovatriptan and/or its metabolites in milk up to four times higher than in plasma.

The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for frovatriptan succinate tablets and any potential adverse effects on the breastfed infant from frovatriptan or from the underlying maternal condition.

The safety and effectiveness in pediatric patients have not been established. Therefore, frovatriptan succinate tablets are not recommended for use in patients under 18 years of age. There are no additional adverse reactions identified in pediatric patients based on postmarketing experience that were not previously identified in adults.

Mean blood concentrations of frovatriptan in elderly patients were 1.5 to 2 times higher than those seen in younger adults [see Clinical Pharmacology (12.3)].   No dosage adjustment is necessary.

 No dosage adjustment is necessary when frovatriptan succinate tablets are given to patients with mild to moderate hepatic impairment.

There is no clinical or pharmacokinetic experience with frovatriptan succinate tablets in patients with severe hepatic impairment. Because a greater than two-fold increase in AUC is predicted in patients with severe hepatic impairment, there is a greater potential for adverse events in these patients, and frovatriptan succinate tablets should therefore be used with caution in that population.

Frovatriptan binds with high affinity to 5-HT_1B/1D receptors. The therapeutic activity of frovatriptan succinate tablets is thought to be due to the agonist effects at the 5-HT_1B/1D receptors on intracranial blood vessels (including the arterio-venous anastomoses) and sensory nerves of the trigeminal system which result in cranial vessel constriction and inhibition of pro-inflammatory neuropeptide release.

The pharmacokinetics of frovatriptan are similar in migraine patients and healthy subjects.

Absorption

Mean maximum blood concentrations (C_max) in patients are achieved approximately 2 to 4 hours after administration of a single oral dose of frovatriptan 2.5 mg. The absolute bioavailability of an oral dose of frovatriptan 2.5 mg in healthy subjects is about 20% in males and 30% in females. Food has no significant effect on the bioavailability of frovatriptan, but delays t_max by one hour.

Distribution

Binding of frovatriptan to serum proteins is low (approximately 15%). Reversible binding to blood cells at equilibrium is approximately 60%, resulting in a blood: plasma ratio of about 2:1 in both males and females. The mean steady state volume of distribution of frovatriptan following intravenous administration of 0.8 mg is 4.2 L/kg in males and 3.0 L/kg in females.

Metabolism

In vitro, cytochrome P450 1A2 appears to be the principal enzyme involved in the metabolism of frovatriptan. Following administration of a single oral dose of radiolabeled frovatriptan 2.5 mg to healthy male and female subjects, 32% of the dose was recovered in urine and 62% in feces. Radiolabeled compounds excreted in urine were unchanged frovatriptan, hydroxylated frovatriptan, N-acetyl desmethyl frovatriptan, hydroxylated N-acetyl desmethyl frovatriptan and desmethyl frovatriptan, together with several other minor metabolites. Desmethyl frovatriptan has lower affinity for 5-HT_1B/1D receptors compared to the parent compound. The N-acetyl desmethyl metabolite has no significant affinity for 5-HT receptors. The activity of the other metabolites is unknown.

Elimination

After an intravenous dose, mean clearance of frovatriptan was 220 and 130 mL/min in males and females, respectively. Renal clearance accounted for about 40% (82 mL/min) and 45% (60 mL/min) of total clearance in males and females, respectively. The mean terminal elimination half-life of frovatriptan in both males and females is approximately 26 hours.

Special Populations

Hepatic Impairment

The AUC of frovatriptan in patients with mild (Child-Pugh 5-6) to moderate (Child-Pugh 7-9) hepatic impairment was about twice that of young, healthy subjects, but within the range observed in healthy elderly subjects and was considerably lower than the values attained with higher doses of frovatriptan (up to 40 mg), which were not associated with any serious adverse effects. There is no clinical or pharmacokinetic experience with frovatriptan succinate tablets in patients with severe hepatic impairment.

Renal Impairment

The pharmacokinetics of frovatriptan following a single oral dose of 2.5 mg was not different in patients with renal impairment (5 males and 6 females, creatinine clearance 16 - 73 mL/min) compared to subjects with normal renal function.

Age

Mean AUC of frovatriptan was 1.5- to 2-fold higher in healthy elderly subjects (age 65 to 77 years) compared to those in healthy younger subjects (age 21 to 37 years). There was no difference in t_max or t_1/2 between the two populations.

Sex

There was no difference in the mean terminal elimination half-life of frovatriptan in males and females. Bioavailability was higher, and systemic exposure to frovatriptan was approximately 2-fold greater, in females than males, irrespective of age.

Race

The effect of race on the pharmacokinetics of frovatriptan has not been examined.

Drug Interaction Studies

Frovatriptan is not an inhibitor of human monoamine oxidase (MAO) enzymes or cytochrome P450 (isozymes 1A2, 2C9, 2C19, 2D6, 2E1, 3A4) in vitro at concentrations up to 250- to 500-fold higher than the highest blood concentrations observed in man at a dose of 2.5 mg. No induction of drug metabolizing enzymes was observed following multiple dosing of frovatriptan to rats or on addition to human hepatocytes in vitro. Although no clinical trials have been performed, it is unlikely that frovatriptan will affect the metabolism of co-administered drugs metabolized by these mechanisms.

Oral Contraceptives

Retrospective analysis of pharmacokinetic data from females across trials indicated that the mean C_max and AUC of frovatriptan are 30% higher in those subjects taking oral contraceptives compared to those not taking oral contraceptives. 

Ergotamine

The AUC and C_max of frovatriptan (2 x 2.5 mg dose) were reduced by approximately 25% when co-administered with ergotamine tartrate [see Contraindications (4) and Drug Interactions (7.1)].

Propranolol

Propranolol increased the AUC of frovatriptan 2.5 mg in males by 60% and in females by 29%. The C_max of frovatriptan was increased 23% in males and 16% in females in the presence of propranolol. The t_max as well as half-life of frovatriptan, though slightly longer in the females, were not affected by concomitant administration of propranolol.

Moclobemide

The pharmacokinetic profile of frovatriptan was unaffected when a single oral dose of frovatriptan 2.5 mg was administered to healthy female subjects receiving the MAO-A inhibitor, moclobemide, at an oral dose of 150 mg twice a day for 8 days.

Carcinogenesis

The carcinogenic potential of orally administered frovatriptan was evaluated in an 84-week study in mice (4, 13, and 40 mg/kg/day), a 104-week study in rats (8.5, 27, and 85 mg/kg/day), and a 26-week study in p53(+/-) transgenic mice (20, 62.5, 200, and 400 mg/kg/day). Although a maximum tolerated dose was not achieved in the 84-week mouse study and in female rats, plasma exposures at the highest doses studied were higher than that achieved in humans at the MRHD of 7.5 mg/day. There were no increases in tumor incidence in the 84-week mouse study at doses producing plasma exposures (AUC) 140 times that in humans at the MRHD. In the rat study, there was a statistically significant increase in the incidence of pituitary adenomas in males only at 85 mg/kg/day, a dose associated with a plasma AUC 250 times that in humans at the MRHD. In the 26-week p53(+/-) transgenic mouse study, the incidence of subcutaneous sarcomas was increased in females at doses of 200 and 400 mg/kg/day.

These sarcomas were associated with subcutaneously implanted animal identification transponders, and are not considered to be relevant to humans. There were no other increases in tumor incidence of any type in any dose group.

Mutagenesis

Frovatriptan was clastogenic in human lymphocyte cultures, in the absence of metabolic activation. In the bacterial reverse mutation assay (Ames test), frovatriptan produced an equivocal response in the absence of metabolic activation. Frovatriptan was negative in an in vitro mouse lymphoma tk assay and an in vivo mouse bone marrow micronucleus test.

Impairment of Fertility

Male and female rats were dosed orally with frovatriptan prior to and during mating and in females up to implantation, at doses of 100, 500, and 1000 mg/kg/day (equivalent to approximately 130, 650, and 1300 times the MRHD on a mg/m² basis). At all dose levels, there was an increase in the number of females that mated on the first day of pairing compared to control animals. This occurred in conjunction with a prolongation of the estrous cycle. In addition, females had a decreased mean number of corpora lutea, and consequently a lower number of live fetuses per litter, which suggested a partial impairment of ovulation. There were no other fertility-related effects.