Naratriptan Drug Information

Dosing Information

The recommended dose of naratriptan tablets is 1 mg or 2.5 mg. If the migraine returns or if the patient has only partial response, the dose may be repeated once after 4 hours, for a maximum dose of 5 mg in a 24-hour period. The safety of treating an average of more than 4 migraine attacks in a 30-day period has not been established.

Dosage Adjustment in Patients With Renal Impairment Naratriptan tablets are contraindicated in

patients with severe renal impairment (creatinine clearance: <15 mL/min) because of decreased clearance of the drug. In patients with mild to moderate renal impairment, the maximum daily dose should not exceed 2.5 mg over a 24-hour period and a 1-mg starting dose is recommended.

Dosage Adjustment in Patients With Hepatic Impairment Naratriptan tablets are contraindicated in

patients with severe hepatic impairment (Child-Pugh Grade C) because of decreased clearance. In patients with mild or moderate hepatic impairment (Child-Pugh Grade A or B), the maximum daily dose should not exceed 2.5 mg over a 24-hour period and a 1-mg starting dose is recommended.

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice. In a long-term open-label trial where patients were allowed to treat multiple migraine attacks for up to 1 year, 15 patients (3.6%) discontinued treatment due to adverse reactions. In controlled clinical trials, the most common adverse reactions were paresthesias, dizziness, drowsiness, malaise/fatigue, and throat/neck symptoms, which occurred at a rate of 2% and at least 2 times placebo rate.

Table 1 lists the adverse reactions that occurred in 5 placebo-controlled clinical trials of approximately 1,752 exposures to placebo and naratriptan tablets in adult patients with migraine. Only reactions that occurred at a frequency of 2% or more in groups treated with naratriptan tablets 2.5 mg and that occurred at a frequency greater than the placebo group in the 5 pooled trials are included in Table 1. Table 1. Adverse Reactions Reported by at Least 2% of Patients Treated With Naratriptan Tablets and at a Frequency Greater Than Placebo Adverse Reaction Percent of Patients Reporting Naratriptan Tablets 1 mg (n = 627) Naratriptan Tablets 2.5 mg (n = 627) Placebo (n = 498) Atypical sensation 2 4 1 Paresthesias (all types) 1 2 <1 Gastrointestinal 6 7 5 Nausea 4 5 4 Neurological 4 7 3 Dizziness 1 2 1 Drowsiness 1 2 <1 Malaise/fatigue 2 2 1 Pain and pressure sensation 2 4 2 Throat/neck symptoms 1 2 1 The incidence of adverse reactions in controlled clinical trials was not affected by age or weight of the patients, duration of headache prior to treatment, presence of aura, use of prophylactic medications, or tobacco use. There were insufficient data to assess the impact of race on the incidence of adverse reactions.

Ergot-Containing Drugs 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 naratriptan within 24 hours of each other is contraindicated.

Other 5-HT 1 Agonists

Concomitant use of other 5-HT 1B/1D agonists (including triptans) within 24 hours of treatment with naratriptan is contraindicated because the risk of vasospastic reactions may be additive.

Selective

Serotonin Reuptake Inhibitors/Serotonin Norepinephrine Reuptake Inhibitors and Serotonin Syndrome Cases of serotonin syndrome have been reported during co-administration of triptans and SSRIs, SNRIs, TCAs, and MAO inhibitors.

Pregnancy Risk Summary There are no adequate data on the developmental risk associated with use of naratriptan in pregnant women. Data from a prospective pregnancy exposure registry and epidemiological studies of pregnant women have documented outcomes in women exposed to naratriptan during pregnancy; however, due to small sample sizes, no definitive conclusions can be drawn regarding the risk of birth defects following exposure to naratriptan. In animal studies, naratriptan produced developmental toxicity (including embryolethality and fetal abnormalities) when administered to pregnant rats and rabbits.

The lowest doses producing evidence of developmental toxicity in animals were associated with plasma exposures 2.5 (rabbit) to 11 (rat) times that in humans at the maximum recommended daily dose (MRDD). 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 of miscarriage was 17%, which were similar to rates reported in women without migraine. Clinical Considerations Disease-Associated Maternal and/or Embryo/Fetal Risk Several studies have suggested that women with migraine may be at increased risk of preeclampsia during pregnancy.

Data Human Data : The numbers of exposed pregnancy outcomes accumulated during the Sumatriptan/Naratriptan/ Treximet® (sumatriptan and naproxen sodium) Pregnancy Registry, a population-based international prospective study that collected data from October 1997 to September 2012, and smaller observational studies, were insufficient to define a level of risk for naratriptan in pregnant women. The Registry documented outcomes of 57 infants and fetuses exposed to naratriptan during pregnancy (52 exposed during the first trimester and 5 exposed during the second trimester). The occurrence of major birth defects (excluding fetal deaths and induced abortions without reported defects and all spontaneous pregnancy losses) during first-trimester exposure to naratriptan was 2.2% (1/46 ) and during any trimester of exposure was 2.0% (1/51). Seven infants were exposed to both naratriptan and sumatriptan in utero, and one of these infants with first-trimester exposure was born with a major birth defect (ventricular septal defect). The sample size in this study had 80% power to detect at least a 3.8- to 4.6- fold increase in the rate of major malformations. In a study using data from the Swedish Medical Birth Register, women who used triptans or ergots during pregnancy were compared with women who did not.

Of the 22 births with first-trimester exposure to naratriptan, one infant was born with malformation (congenital deformity of the hand). Animal Data : When naratriptan was administered to pregnant rats during the period of organogenesis at doses of 10, 60, or 340 mg/kg/day, there was a dose-related increase in embryonic death; incidences of fetal structural variations (incomplete/irregular ossification of skull bones, sternebrae, ribs) were increased at all doses. The maternal plasma exposures (AUC) at these doses were approximately 11, 70, and 470 times the exposure in humans at the MRDD. The high dose was maternally toxic, as evidenced by decreased maternal body weight gain during gestation. A no-effect dose for developmental toxicity in rats exposed during organogenesis was not established.

When naratriptan was administered orally (1, 5, or 30 mg/kg/day) to pregnant Dutch rabbits throughout organogenesis, the incidence of a specific fetal skeletal malformation (fused sternebrae) was increased at the high dose, the incidence of fetal variations (major blood vessel variations, supernumerary ribs, incomplete skeletal ossification) was increased at the mid and high doses, and embryonic death was increased at all doses (4, 20, and 120 times, respectively, the MRDD on a body surface area basis). Maternal toxicity (decreased body weight gain) was evident at the high dose. In a similar study in New Zealand White rabbits (1, 5, or 30 mg/kg/day throughout organogenesis), decreased fetal weights and increased incidences of fetal skeletal variations were observed at all doses (maternal exposures equivalent to 2.5, 19, and 140 times exposure in humans receiving the MRDD), while maternal body weight gain was reduced at 5 mg/kg or greater. A no-effect dose for developmental toxicity in rabbits exposed during organogenesis was not established.

When female rats were treated orally with naratriptan (10, 60, or 340 mg/kg/day) during late gestation and lactation, offspring behavioral impairment (tremors) and decreased offspring viability and growth were observed at doses of 60 mg/kg or greater, while maternal toxicity occurred only at the highest dose. Maternal exposures at the no-effect dose for developmental effects in this study were approximately 11 times the exposure in humans receiving the MRDD.

Pediatric Use Safety and effectiveness in pediatric patients have not been established. Therefore, naratriptan is not recommended for use in patients younger than18 years of age. One controlled clinical trial evaluated naratriptan tablets (0.25 to 2.5 mg) in 300 adolescent migraineurs aged 12 to 17 years who received at least 1 dose of naratriptan tablets for an acute migraine.

In this study, 54% of the patients were female and 89% were Caucasian. There were no statistically significant differences between any of the treatment groups. The headache response rates at 4 hours (n) were 65% (n = 74), 67% (n = 78), and 64% (n = 70) for placebo, 1-mg, and 2.5-mg groups, respectively.

This trial did not establish the efficacy of naratriptan compared with placebo in the treatment of migraine in adolescents. Adverse reactions observed in this clinical trial were similar in nature to those reported in clinical trials in adults.

Naratriptan tablets are contraindicated in patients with: Ischemic coronary artery disease (CAD) (angina pectoris, history of myocardial infarction, or documented silent ischemia) or coronary artery vasospasm, including Prinzmetal's angina Wolff-Parkinson-White syndrome or arrhythmias associated with other cardiac accessory conduction pathway disorders History of stroke or transient ischemic attack (TIA) or history of hemiplegic or basilar migraine because such patients are at a higher risk of stroke Peripheral vascular disease Ischemic bowel disease Uncontrolled hypertension Recent use (i.e., within 24 hours) of another 5-HT 1 agonist, ergotamine-containing medication, ergot-type medication (such as dihydroergotamine or methysergide) Hypersensitivity to naratriptan (angioedema and anaphylaxis seen) Severe renal or hepatic impairment History of coronary artery disease or coronary artery vasospasm Wolff-Parkinson-White syndrome or other cardiac accessory conduction pathway disorders History of stroke, transient ischemic attack, or hemiplegic or basilar migraine Peripheral vascular disease Ischemic bowel disease Uncontrolled hypertension Recent (within 24 hours) use of another 5-HT 1 agonist (e.g., another triptan) or an ergotamine-containing medication Hypersensitivity to naratriptan (angioedema and anaphylaxis seen) Severe renal or hepatic impairment

Adverse reactions observed after overdoses of up to 25 mg included increases in blood pressure resulting in lightheadedness, neck tension, tiredness, and loss of coordination. Also, ischemic ECG changes likely due to coronary artery vasospasm have been reported. The elimination half-life of naratriptan is about 6 hours, and therefore monitoring of patients after overdose with naratriptan should continue for at least 24 hours or while symptoms or signs persist.

There is no specific antidote to naratriptan. It is unknown what effect hemodialysis or peritoneal dialysis has on the serum concentrations of naratriptan.