Sumatriptan precautions

List of precautions
General Binding to melanin-containing tissues Corneal opacities Lab tests Drug/laboratory test interactions Carcinogenesis Mutagenesis Impairment of fertility Pregnancy Nursing mothers Pediatric use Geriatric use
 * Chest discomfort/jaw or neck tightness
 * Impaired hepatic/renal function
 * Seizure
 * Neurologic conditions
 * Embryolethality
 * Teratogenicity
 * Pup deaths
 * Pregnancy registry

General
For a given attack, if a patient does not respond to the first dose of sumatriptan, the diagnosis of migraine headache should be reconsidered before administration of a second dose. Overuse of acute migraine treatments has been associated with the exacerbation of headache (medication overuse headache) in susceptible patients. Withdrawal of the treatment may be necessary. Return to top

Chest discomfort/jaw or neck tightness
Chest discomfort and jaw or neck tightness have been reported infrequently following the administration of Imitrex Nasal Spray and have also been reported following use of IMITREX Tablets. Chest, jaw, or neck tightness is relatively common after administration of IMITREX Injection. Only rarely have these symptoms been associated with ischemic ECG changes. However, because sumatriptan may cause coronary artery vasospasm, patients who experience signs or symptoms suggestive of angina following sumatriptan should be evaluated for the presence of CAD or a predisposition to Prinzmetal variant angina before receiving additional doses of sumatriptan, and should be monitored electrocardiographically if dosing is resumed and similar symptoms recur. Similarly, patients who experience other symptoms or signs suggestive of decreased arterial flow, such as ischemic bowel syndrome or Raynaud syndrome following sumatriptan should be evaluated for atherosclerosis or predisposition to vasospasm. Return to top

Impaired hepatic/renal function
Imitrex Nasal Spray should also be administered with caution to patients with diseases that may alter the absorption, metabolism, or excretion of drugs, such as impaired hepatic or renal function. Return to top

Seizure
There have been rare reports of seizure following administration of sumatriptan. Sumatriptan should be used with caution in patients with a history of epilepsy or conditions associated with a lowered seizure threshold. Return to top

Neurologic conditions
Care should be taken to exclude other potentially serious neurologic conditions before treating headache in patients not previously diagnosed with migraine headache or who experience a headache that is atypical for them. There have been rare reports where patients received sumatriptan for severe headaches that were subsequently shown to have been secondary to an evolving neurologic lesion. Return to top

Binding to melanin-containing tissues
In rats treated with a single subcutaneous dose (0.5 mg/kg) or oral dose (2 mg/kg) of radiolabeled sumatriptan, the elimination half-life of radioactivity from the eye was 15 and 23 days, respectively, suggesting that sumatriptan and/or its metabolites bind to the melanin of the eye. Comparable studies were not performed by the intranasal route. Because there could be an accumulation in melanin-rich tissues over time, this raises the possibility that sumatriptan could cause toxicity in these tissues after extended use. However, no effects on the retina related to treatment with sumatriptan were noted in any of the oral or subcutaneous toxicity studies. Although no systematic monitoring of ophthalmologic function was undertaken in clinical trials, and no specific recommendations for ophthalmologic monitoring are offered, prescribers should be aware of the possibility of long-term ophthalmologic effects. Return to top

Corneal opacities
Sumatriptan causes corneal opacities and defects in the corneal epithelium in dogs; this raises the possibility that these changes may occur in humans. While patients were not systematically evaluated for these changes in clinical trials, and no specific recommendations for monitoring are being offered, prescribers should be aware of the possibility of these changes. Return to top

Lab tests
No specific laboratory tests are recommended for monitoring patients prior to and/or after treatment with sumatriptan. Return to top

Drug/laboratory test interactions
Imitrex Nasal Spray is not known to interfere with commonly employed clinical laboratory tests. Return to top

Carcinogenesis
In carcinogenicity studies, rats and mice were given sumatriptan by oral gavage (rats, 104 weeks) or drinking water (mice, 78 weeks). Average exposures achieved in mice receiving the highest dose (target dose of 160 mg/kg/day) were approximately 184 times the exposure attained in humans after the maximum recommended single intranasal dose of 20 mg. The highest dose administered to rats (160 mg/kg/day, reduced from 360 mg/kg/day during week 21) was approximately 78 times the maximum recommended single intranasal dose of 20 mg on a mg/m2 basis. There was no evidence of an increase in tumors in either species related to sumatriptan administration. Local effects on nasal and respiratory tissue after chronic intranasal dosing in animals have not been evaluated. Return to top

Mutagenesis
Sumatriptan was not mutagenic in the presence or absence of metabolic activation when tested in 2 gene mutation assays (the Ames test and the in vitro mammalian Chinese hamster V79/HGPRT assay). In 2 cytogenetics assays (the in vitro human lymphocyte assay and the in vivo rat micronucleus assay) sumatriptan was not associated with clastogenic activity. Return to top

Impairment of fertility
In a study in which male and female rats were dosed daily with oral sumatriptan prior to and throughout the mating period, there was a treatment-related decrease in fertility secondary to a decrease in mating in animals treated with 50 and 500 mg/kg/day. The highest no-effect dose for this finding was 5 mg/kg/day, or approximately twice the maximum recommended single human intranasal dose of 20 mg on a mg/m2 basis. It is not clear whether the problem is associated with treatment of the males or females or both combined. In a similar study by the subcutaneous route there was no evidence of impaired fertility at 60 mg/kg/day, the maximum dose tested, which is equivalent to approximately 29 times the maximum recommended single human intranasal dose of 20 mg on a mg/m2 basis. Fertility studies, in which sumatriptan was administered by the intranasal route, were not conducted. Return to top

Pregnancy
Pregnancy Category C. In reproductive toxicity studies in rats and rabbits, oral treatment with sumatriptan was associated with embryolethality, fetal abnormalities, and pup mortality. When administered by the intravenous route to rabbits, sumatriptan has been shown to be embryolethal. Reproductive toxicity studies for sumatriptan by the intranasal route have not been conducted. There are no adequate and well-controlled studies in pregnant women. Therefore, Imitrex Nasal Spray should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. In assessing this information, the following findings should be considered. Return to top

Embryolethality
When given orally or intravenously to pregnant rabbits daily throughout the period of organogenesis, sumatriptan caused embryolethality at doses at or close to those producing maternal toxicity. In the oral studies this dose was 100 mg/kg/day, and in the intravenous studies this dose was 2.0 mg/kg/day. The mechanism of the embryolethality is not known. The highest no-effect dose for embryolethality by the oral route was 50 mg/kg/day, which is approximately 48 times the maximum single recommended human intranasal dose of 20 mg on a mg/m2 basis. By the intravenous route, the highest no-effect dose was 0.75 mg/kg/day, or approximately 0.7 times the maximum single recommended human intranasal dose of 20 mg on a mg/m2 basis. The intravenous administration of sumatriptan to pregnant rats throughout organogenesis at 12.5 mg/kg/day, the maximum dose tested, did not cause embryolethality. This dose is approximately 6 times the maximum single recommended human intranasal dose of 20 mg on a mg/m2 basis. Additionally, in a study in rats given subcutaneous sumatriptan daily, prior to and throughout pregnancy, at 60 mg/kg/day, the maximum dose tested, there was no evidence of increased embryo/fetal lethality. This dose is equivalent to approximately 29 times the maximum recommended single human intranasal dose of 20 mg on a mg/m2 basis. Return to top

Teratogenicity
Oral treatment of pregnant rats with sumatriptan during the period of organogenesis resulted in an increased incidence of blood vessel abnormalities (cervicothoracic and umbilical) at doses of approximately 250 mg/kg/day or higher. The highest no-effect dose was approximately 60 mg/kg/day, which is approximately 29 times the maximum single recommended human intranasal dose of 20 mg on a mg/m2 basis. Oral treatment of pregnant rabbits with sumatriptan during the period of organogenesis resulted in an increased incidence of cervicothoracic vascular and skeletal abnormalities. The highest no-effect dose for these effects was 15 mg/kg/day, or approximately 14 times the maximum single recommended human intranasal dose of 20 mg on a mg/m2 basis. A study in which rats were dosed daily with oral sumatriptan prior to and throughout gestation demonstrated embryo/fetal toxicity (decreased body weight, decreased ossification, increased incidence of rib variations) and an increased incidence of a syndrome of malformations (short tail/short body and vertebral disorganization) at 500 mg/kg/day. The highest no-effect dose was 50 mg/kg/day, or approximately 24 times the maximum single recommended human intranasal dose of 20 mg on a mg/m2 basis. In a study in rats dosed daily with subcutaneous sumatriptan prior to and throughout pregnancy, at a dose of 60 mg/kg/day, the maximum dose tested, there was no evidence of teratogenicity. This dose is equivalent to approximately 29 times the maximum recommended single human intranasal dose of 20 mg on a mg/m2 basis. Return to top

Pup deaths
Oral treatment of pregnant rats with sumatriptan during the period of organogenesis resulted in a decrease in pup survival between birth and postnatal day 4 at doses of approximately 250 mg/kg/day or higher. The highest no-effect dose for this effect was approximately 60 mg/kg/day, or 29 times the maximum single recommended human intranasal dose of 20 mg on a mg/m2 basis. Oral treatment of pregnant rats with sumatriptan from gestational day 17 through postnatal day 21 demonstrated a decrease in pup survival measured at postnatal days 2, 4, and 20 at the dose of 1,000 mg/kg/day. The highest no-effect dose for this finding was 100 mg/kg/day, approximately 49 times the maximum single recommended human intranasal dose of 20 mg on a mg/m2 basis. In a similar study in rats by the subcutaneous route there was no increase in pup death at 81 mg/kg/day, the highest dose tested, which is equivalent to 40 times the maximum single recommended human intranasal dose of 20 mg on a mg/m2 basis. Return to top

Pregnancy registry
To monitor fetal outcomes of pregnant women exposed to IMITREX, GlaxoSmithKline maintains a Sumatriptan Pregnancy Registry. Physicians are encouraged to register patients by calling (800) 336-2176. Return to top

Nursing mothers
Sumatriptan is excreted in human breast milk following subcutaneous administration. Infant exposure to sumatriptan can be minimized by avoiding breastfeeding for 12 hours after treatment with Imitrex Nasal Spray. Return to top

Pediatric use
Safety and effectiveness of Imitrex Nasal Spray in pediatric patients under 18 years of age have not been established; therefore, Imitrex Nasal Spray is not recommended for use in patients under 18 years of age. Two controlled clinical trials evaluating sumatriptan nasal spray (5 to 20 mg) in pediatric patients aged 12 to 17 years enrolled a total of 1,248 adolescent migraineurs who treated a single attack. The studies did not establish the efficacy of sumatriptan nasal spray compared to placebo in the treatment of migraine in adolescents. Adverse events observed in these clinical trials were similar in nature to those reported in clinical trials in adults. Five controlled clinical trials (2 single attack studies, 3 multiple attack studies) evaluating oral sumatriptan (25 to 100 mg) in pediatric patients aged 12 to 17 years enrolled a total of 701 adolescent migraineurs. These studies did not establish the efficacy of oral sumatriptan compared to placebo in the treatment of migraine in adolescents. Adverse events observed in these clinical trials were similar in nature to those reported in clinical trials in adults. The frequency of all adverse events in these patients appeared to be both dose- and age-dependent, with younger patients reporting events more commonly than older adolescents. Postmarketing experience documents that serious adverse events have occurred in the pediatric population after use of subcutaneous, oral, and/or intranasal sumatriptan. These reports include events similar in nature to those reported rarely in adults, including stroke, visual loss, and death. A myocardial infarction has been reported in a 14-year-old male following the use of oral sumatriptan; clinical signs occurred within 1 day of drug administration. Since clinical data to determine the frequency of serious adverse events in pediatric patients who might receive injectable, oral, or intranasal sumatriptan are not presently available, the use of sumatriptan in patients aged younger than 18 years is not recommended. Return to top

Geriatric use
The use of sumatriptan in elderly patients is not recommended because elderly patients are more likely to have decreased hepatic function, they are at higher risk for CAD, and blood pressure increases may be more pronounced in the elderly. Return to top