DIHYDROERGOTAMINE Drug Interactions: What You Need to Know

Drug Interactions Vasoconstrictors Dihydroergotamine mesylate Nasal Spray should not be used with peripheral vasoconstrictors because the combination may cause synergistic elevation of blood pressure.

Sumatriptan

Sumatriptan has been reported to cause coronary artery vasospasm, and its effect could be additive with dihydroergotamine mesylate nasal spray. Sumatriptan and dihydroergotamine mesylate nasal spray should not be taken within 24 hours of each other. (See CONTRAINDICATIONS )

Beta Blockers

Although the results of a clinical study did not indicate a safety problem associated with the administration of dihydroergotamine mesylate nasal spray to subjects already receiving propranolol, there have been reports that propranolol may potentiate the vasoconstrictive action of ergotamine by blocking the vasodilating property of epinephrine.

Nicotine

Nicotine may provoke vasoconstriction in some patients, predisposing to a greater ischemic response to ergot therapy. CYP 3A4 Inhibitors (e.g.

Macrolide

Antibiotics and Protease Inhibitors) See CONTRAINDICATIONS and WARNINGS . SSRI's Weakness, hyperreflexia, and incoordination have been reported rarely when 5HT 1 agonists have been coadministered with SSRI's (e.g., fluoxetine, fluvoxamine, paroxetine, sertraline). There have been no reported cases from spontaneous reports of drug interaction between SSRI's and dihydroergotamine mesylate nasal spray or D.H.E. 45.

Oral Contraceptives

The effect of oral contraceptives on the pharmacokinetics of dihydroergotamine mesylate nasal spray has not been studied. Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenesis In a 2-year mouse carcinogenicity study, subcutaneous administration of dihydroergotamine mesylate (0, 0.5, 1.5 or 5 mg/kg/day) resulted in an increased incidence of fibrosarcoma at the injection sites in males and females at the high dose. In a 2-year rat carcinogenicity study, intranasal administration of dihydroergotamine mesylate (0, 0.4, 0.8 or 1.6 mg/day for 13 weeks, followed by 0, 0.08, 0.24 or 0.8 mg/day for the remainder of the study) did not result in an increase in tumors.

Mutagenesis

Dihydroergotamine mesylate was clastogenic in two in vitro chromosomal aberration assays, the V79 Chinese hamster cell assay with metabolic activation and the cultured human peripheral blood lymphocyte assay. There was no evidence of mutagenic potential when dihydroergotamine mesylate was tested in the presence or absence of metabolic activation in two gene mutation assays (the Ames test and the in vitro mammalian Chinese hamster V79/HGPRT assay) and in an assay for DNA damage (the rat hepatocyte unscheduled DNA synthesis test). Dihydroergotamine was not clastogenic in the in vivo mouse and hamster micronucleus tests. Impairment of Fertility Intranasal administration of dihydroergotamine to rats at doses up to 1.6 mg/day was not associated with adverse effects on fertility.

Pregnancy Risk Summary

Available data from published literature indicate an increased risk of preterm delivery with dihydroergotamine mesylate use during pregnancy. Avoid use of dihydroergotamine mesylate nasal spray during pregnancy (see WARNINGS ). Data collected over decades have shown no increased risk of major birth defects or miscarriage with the use of dihydroergotamine mesylate during pregnancy. In animal reproduction studies, adverse effects on development were observed following intranasal administration of dihydroergotamine mesylate during pregnancy (decreased fetal body weight and/or skeletal ossification) in rats and rabbits or during pregnancy and lactation in rats (decreased body weight and impaired reproductive function in the offspring) at doses that were not associated with maternal toxicity (see Data). The estimated rate of major birth defects (2.2% to 2.9%) and miscarriage (17%) among deliveries to women with migraine are similar to rates reported in women without migraine. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriages in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Data Animal Data

Intranasal administration of dihydroergotamine mesylate to pregnant rats throughout the period of organogenesis resulted in decreased fetal body weight and/or skeletal ossification at doses of 0.16 mg/day and greater. A no-effect level for adverse effects on embryofetal development was not identified in rats. Intranasal administration of dihydroergotamine mesylate to pregnant rabbits throughout organogenesis resulted in decreased skeletal ossification at 3.6 mg/day. The no-effect dose for adverse effects on embryofetal development in rabbits was 1.2 mg/day. Intranasal administration of dihydroergotamine mesylate to female rats throughout pregnancy and lactation resulted in decreased body weight and impaired reproductive function (decreased mating indices) in the offspring at doses of 0.16 mg/day or greater. A no-effect dose for adverse effects on pre and postnatal development in rats was not established. Effects on offspring development occurred at doses below those that produced evidence of maternal toxicity in these studies. Dihydroergotamine-induced intrauterine growth retardation has been attributed to reduced uteroplacental blood flow resulting from prolonged vasoconstriction of the uterine vessels and/or increased myometrial tone.

Nursing Mothers

There are no data on the presence of dihydroergotamine in human milk; however, ergotamine, a related drug, is present in human milk. There are reports of diarrhea, vomiting, weak pulse, and unstable blood pressure in breastfed infants exposed to ergotamine. Dihydroergotamine mesylate may reduce milk supply because it may decrease prolactin levels. Because of the potential for reduced milk supply and serious adverse events in the breastfed infant, including diarrhea, vomiting, weak pulse, and unstable blood pressure, advise patients not to breastfeed during treatment with dihydroergotamine mesylate nasal spray and for 3 days after the last dose. Breast milk supply during this time should be pumped and discarded.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established. Use in the Elderly There is no information about the safety and effectiveness of dihydroergotamine mesylate nasal spray in this population because patients over age 65 were excluded from the controlled clinical trials.

CONTRAINDICATIONS There have been a few reports of serious adverse events associated with the coadministration of dihydroergotamine and potent CYP3A4 inhibitors, such as protease inhibitors and macrolide antibiotics, resulting in vasospasm that led to cerebral ischemia and/or ischemia of the extremities. The use of potent CYP3A4 inhibitors (i.e., ritonavir, nelfinavir, indinavir, erythromycin, clarithromycin, troleandomycin, ketoconazole, itraconazole) with dihydroergotamine is, therefore, contraindicated (see WARNINGS, CYP3A4 Inhibitors ).

Dihydroergotamine Mesylate

Injection, USP should not be given to patients with ischemic heart disease (e.g., angina pectoris, history of myocardial infarction, or documented silent ischemia) or to patients who have clinical symptoms or findings consistent with coronary artery vasospasm including Prinzmetal's variant angina (see WARNINGS ).

Because Dihydroergotamine Mesylate

Injection, USP may increase blood pressure, it should not be given to patients with uncontrolled hypertension.

Dihydroergotamine Mesylate

Injection, USP, 5-HT 1 agonists (e.g., sumatriptan), ergotamine-containing or ergot-type medications or methysergide should not be used within 24 hours of each other.

Dihydroergotamine Mesylate

Injection, USP should not be administered to patients with hemiplegic or basilar migraine. In addition to those conditions mentioned above, Dihydroergotamine Mesylate Injection, USP is also contraindicated in patients with known peripheral arterial disease, sepsis, following vascular surgery and severely impaired hepatic or renal function.

Dihydroergotamine Mesylate

Injection, USP is contraindicated in patients who have previously shown hypersensitivity to ergot alkaloids. Dihydroergotamine mesylate should not be used with peripheral and central vasoconstrictors because the combination may result in additive or synergistic elevation of blood pressure.

WARNINGS Dihydroergotamine mesylate nasal spray should only be used where a clear diagnosis of migraine headache has been established. CYP 3A4 Inhibitors (e.g., Macrolide Antibiotics and Protease Inhibitors) There have been rare reports of serious adverse events in connection with the coadministration of dihydroergotamine and potent CYP 3A4 inhibitors, such as protease inhibitors and macrolide antibiotics, resulting in vasospasm that led to cerebral ischemia and/or and ischemia of the extremities. The use of potent CYP 3A4 inhibitors with dihydroergotamine should therefore be avoided (see CONTRAINDICATIONS) . Examples of some of the more potent CYP 3A4 inhibitors include: antifungals ketoconazole and itraconazole, the protease inhibitors ritonavir, nelfinavir, and indinavir, and macrolide antibiotics erythromycin, clarithromycin, and troleandomycin. Other less potent CYP 3A4 inhibitors should be administered with caution. Less potent inhibitors include saquinavir, nefazodone, fluconazole, grapefruit juice, fluoxetine, fluvoxamine, zileuton, and clotrimazole. These lists are not exhaustive, and the prescriber should consider the effects on CYP 3A4 of other agents being considered for concomitant use with dihydroergotamine.

Fibrotic Complications

There have been reports of pleural and retroperitoneal fibrosis in patients following prolonged daily use of injectable dihydroergotamine mesylate. Rarely, prolonged daily use of other ergot alkaloid drugs has been associated with cardiac valvular fibrosis. Rare cases have also been reported in association with the use of injectable dihydroergotamine mesylate; however, in those cases, patients also received drugs known to be associated with cardiac valvular fibrosis. Administration of dihydroergotamine mesylate nasal spray, should not exceed the dosing guidelines and should not be used for chronic daily administration ( see DOSAGE AND ADMINISTRATION ). Risk of Myocardial Ischemia and/or Infarction and Other Adverse Cardiac Events: Dihydroergotamine mesylate nasal spray should not be used by patients with documented ischemic or vasospastic coronary artery disease (see CONTRAINDICATIONS). It is strongly recommended that dihydroergotamine mesylate nasal spray not be given to patients in whom unrecognized coronary artery disease (CAD) is predicted by the presence of risk factors (e.g., hypertension, hypercholesterolemia, smoker, obesity, diabetes , strong family history of CAD, females who are surgically or physiologically postmenopausal, or males who are over 40 years of age) unless a cardiovascular evaluation provides satisfactory clinical evidence that the patient is reasonably free of coronary artery and ischemic myocardial disease or other significant underlying cardiovascular disease. The sensitivity of cardiac diagnostic procedures to detect cardiovascular disease or predisposition to coronary artery vasospasm is modest, at best. If, during the cardiovascular evaluation, the patient's medical history or electrocardiographic investigations reveal findings indicative of or consistent with coronary artery vasospasm or myocardial ischemia, dihydroergotamine mesylate nasal spray should not be administered (see CONTRAINDICATIONS). For patients with risk factors predictive of CAD who are determined to have a satisfactory cardiovascular evaluation, it is strongly recommended that administration of the first dose of dihydroergotamine mesylate nasal spray take place in the setting of a physician's office or similar medically staffed and equipped facility unless the patient has previously received dihydroergotamine mesylate. Because cardiac ischemia can occur in the absence of clinical symptoms, consideration should be given to obtaining on the first occasion of use an electrocardiogram (ECG) during the interval immediately following dihydroergotamine mesylate nasal spray, in these patients with risk factors. It is recommended that patients who are intermittent long-term users of dihydroergotamine mesylate nasal spray and who have or acquire risk factors predictive of CAD, as described above, undergo periodic interval cardiovascular evaluation as they continue to use dihydroergotamine mesylate nasal spray. The systematic approach described above is currently recommended as a method to identify patients in whom dihydroergotamine mesylate nasal spray may be used to treat migraine headaches with an acceptable margin of cardiovascular safety.

Cardiac

Events and Fatalities No deaths have been reported in patients using dihydroergotamine mesylate nasal spray. However, the potential for adverse cardiac events exists. Serious adverse cardiac events, including acute myocardial infarction, life-threatening disturbances of cardiac rhythm, and death have been reported to have occurred following the administration of dihydroergotamine mesylate injection. Considering the extent of use of dihydroergotamine mesylate in patients with migraine, the incidence of these events is extremely low. Drug-Associated Cerebrovascular Events and Fatalities Cerebral hemorrhage, subarachnoid hemorrhage, stroke, and other cerebrovascular events have been reported in patients treated with dihydroergotamine mesylate injection; and some have resulted in fatalities. In a number of cases, it appears possible that the cerebrovascular events were primary, the dihydroergotamine mesylate injection having been administered in the incorrect belief that the symptoms experienced were a consequence of migraine, when they were not. It should be noted that patients with migraine may be at increased risk of certain cerebrovascular events (e.g., stroke, hemorrhage, transient ischemic attack).

Other Vasospasm Related Events

Dihydroergotamine mesylate nasal spray, like other ergot alkaloids, may cause vasospastic reactions other than coronary artery vasospasm. Myocardial and peripheral vascular ischemia have been reported with dihydroergotamine mesylate nasal spray. Dihydroergotamine mesylate nasal spray associated vasospastic phenomena may also cause muscle pains, numbness, coldness, pallor, and cyanosis of the digits. In patients with compromised circulation, persistent vasospasm may result in gangrene or death, dihydroergotamine mesylate nasal spray should be discontinued immediately if signs or symptoms of vasoconstriction develop. Increase in Blood Pressure Significant elevation in blood pressure has been reported on rare occasions in patients with and without a history of hypertension treated with dihydroergotamine mesylate nasal spray and dihydroergotamine mesylate injection. Dihydroergotamine mesylate nasal spray is contraindicated in patients with uncontrolled hypertension (see CONTRAINDICATIONS).

An

18% increase in mean pulmonary artery pressure was seen following dosing with another 5HT1 agonist in a study evaluating subjects undergoing cardiac catheterization.

Local Irritation Approximately

30% of patients using dihydroergotamine mesylate nasal spray (compared to 9% of placebo patients) have reported irritation in the nose, throat, and/or disturbances in taste. Irritative symptoms include congestion, burning sensation, dryness, paraesthesia, discharge, epistaxis, pain, or soreness. The symptoms were predominantly mild to moderate in severity and transient. In approximately 70% of the above mentioned cases, the symptoms resolved within four hours after dosing with dihydroergotamine mesylate nasal spray. Examinations of the nose and throat in a small subset (N = 66) of study participants treated for up to 36 months (range 1-36 months) did not reveal any clinically noticeable injury. Other than this limited number of patients, the consequences of extended and repeated use of dihydroergotamine mesylate nasal spray on the nasal and/or respiratory mucosa have not been systematically evaluated in patients. Nasal tissue in animals treated with dihydroergotamine mesylate daily at nasal cavity surface area exposures (in mg/mm 2 ) that were equal to or less than those achieved in humans receiving the maximum recommended daily dose of 0.08 mg/kg/day showed mild mucosal irritation characterized by mucous cell and transitional cell hyperplasia and squamous cell metaplasia. Changes in rat nasal mucosa at 64 weeks were less severe than at 13 weeks. Local effects on respiratory tissue after chronic intranasal dosing in animals have not been evaluated.

Medication Overuse Headache

Overuse of acute migraine drugs (e.g., ergotamines, triptans, opioids, or a combination of these drugs for 10 or more days per month) may lead to exacerbation of headache (i.e., 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.

Preterm Labor

Based on the mechanism of action of dihydroergotamine and findings from the published literature, dihydroergotamine mesylate nasal spray may cause preterm labor. Avoid use of dihydroergotamine mesylate nasal spray during pregnancy ( see PRECAUTIONS ).