 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Dihydroergotamine
D.H.E. 45 (dihydroergotamine mesylate) Injection, USP Rx only D.H.E. 45® is ergotamine hydrogenated in the 9, 10 position as the mesylate salt. D.H.E. 45® is known chemically as ergotaman-3',6',18-trione,9,10-dihydro-12'-hydroxy-2'-methyl-5'- (phenylmethyl) (5'a)-, monomethanesulfonate. Its molecular weight is 679. 80 and its empirical formula is C13H37N5O5 · CH4O3S. D.H.E. 45® (dihydroergotamine mesylate) Injection, USP is a clear, colorless solution supplied in sterile ampuls for I.V., I.M. , or subcutaneous administration containing per mL:
Mechanism of Action Dihydroergotamine binds with high affinity to 5-HT1Da and 5-HT1Db receptors. It also binds with high affinity to serotonin 5-HT1A, 5-HT2A, and 5-HT2C receptors, noradrenaline a2A, a2B and a receptors, and dopamine D2L and D3 receptors. The therapeutic activity of dihydroergotamine in migraine is generally attributed to the agonist effect at 5-HT1D receptors. Two current theories have been proposed to explain the efficacy of 5-HT1D receptor agonists in migraine. One theory suggests that activation of 5-HT1D receptors located on intracranial blood vessels, including those on arterio-venous anastomoses, leads to vasoconstriction, which correlates with the relief of migraine headache. The alternative hypothesis suggests that activation of 5-HT1D receptors on sensory nerve endings of the trigeminal system results in the inhibition of pro-inflammatory neuropeptide release. In addition, dihydroergotamine possesses oxytocic properties. (See CONTRAINDICATIONS) Pharmacokinetics Absorption: Absolute bioavailability for the subcutaneous and intramuscular route have not been determined however, no difference was observed in dihydroergotamine bioavailability from intramuscular and subcutaneous doses. Dihydroergotamine mesylate is poorly bioavailable following oral administration. Distribution: Dihydroergotamine mesylate is 93% plasma protein bound. The apparent steady-state volume of distribution is approximately 800 liters. Metabolism: Four dihydroergotamine mesylate metabolites have been identified in human plasma following oral administration. The major metabolite 8'-b-hydroxydihydroergotamine, exhibits affinity equivalent to its parent for adrenergic and 5-HT receptors and demonstrates equivalent potency in several venoconstrictor activity models, in vivo and in vitro. The other metabolites, i.e., dihydrolysergic acid, dihydrolysergic amide and a metabolite formed by oxidative opening of the proline ring are of minor importance. Following nasal administration, total metabolites represent only 20%-30% of plasma AUC. Quantitative pharmacokinetic characterization of the four metabolites has not been performed. Excretion: The major excretory route of dihydroergotamine is via the bile in the feces. The total body clearance is 1.5 L/min which reflects mainly hepatic clearance. Only 6%-7% of unchanged dihydroergotamine is excreted in the urine after intramuscular injection. The renal clearance (0.1 L/min) is unaffected by the route of dihydroergotamine administration. The decline of plasma dihydroergotamine after intramuscular or intravenous administration is multi-exponential with a terminal half-life of about 9 hours. Subpopulations: No studies have been conducted on the effect of renal or hepatic impairment, gender race, or ethnicity on dihydroergotamine pharmacokinetics. D.H.E. 45® (dihydroergotamine mesylate) Injection, USP is contraindicated in patients with severely impaired hepatic or renal function. (See CONTRAINDICATIONS) Interactions: Pharmacokinetic interactions (increased
blood levels) have been reported in patients treated orally with
dihydroergotamine and macrolide
antibiotics, principally troleandomycin, presumably due to inhibition
of cytochrome P450
3A metabolism of
dihydroergotamine by troleandomycin. Dihydroergotamine has also
been shown to be an inhibitor
of cytochrome P450 3A catalyzed reactions. No
pharmacokinetic interactions involving other cytochrome
P450 isoenzymes are known.
D.H.E. 45® (dihydroergotamine mesylate) Injection, USP is indicated for the acute treatment of migraine headaches with or without aura and the acute treatment of cluster headache episodes.
D.H.E. 45® (dihydroergotamine mesylate) Injection, USP should be administered in a dose of 1 mL intravenously, intramuscularly or subcutaneously. The dose can be repeated, as needed, at 1 hour intervals to a total dose of 3 mL for intramuscular or subcutaneous delivery or 2 mL for intravenous delivery in a 24 hour period. The total weekly dosage should not exceed 6 mL. HOW SUPPLIED D.H.E. 45® (dihydroergotamine mesylate) Injection, USP Available as a clear, colorless, sterile solution in single 1 mL sterile ampuls containing 1 mg of dihydroergotamine mesylate per mL, in packages of 10 (NDC 0078-0041-01). Store below 77° F(25° C), in light-resistant containers.
Do not refrigerate or freeze. To assure constant
potency, protect the ampuls from light
and heat. Administer only if clear and colorless.
Serious cardiac events, including some that have been fatal, have occurred following use of D.H.E. 45® (dihydroergotamine mesylate) Injection, USP, but are extremely rare. Events reported have included coronary artery vasospasm, transient myocardial ischemia, myocardial infarction, ventricular tachycardia, and ventricular fibrillation. ( See CONTRAINDICATIONS, WARNINGS, and PRECAUTIONS) Post-Introduction Reports The following events derive from postmarketing experience have been occasionally reported in patients receiving D.H.E. 45® (dihydroergotamine mesylate) Injection, USP vasospasm, paraesthesia, hypertension, dizziness, anxiety, dyspnea, headache, flushing, diarrhea, rash, increased sweating, and pleural and retroperitoneal fibrosis after long-term use of dihydroergotamine. Extremely rare cases of myocardial infarction and stroke have been reported. A causal relationship has not been established. D.H.E. 45® (dihydroergotamine mesylate) Injection, USP is not recommended for prolonged daily use. (See DOSAGE AND ADMINISTRATION) DRUG ABUSE AND DEPENDENCE Currently available data have not demonstrated drug
abuse or psychological
dependence with dihydroergotamine. However, cases of drug
abuse and psychological
dependence in patients on other forms of ergot
therapy have been reported.
That, due to the chronicity
of vascular headaches,
it is imperative
that patients be advised not to exceed recommended dosages.
Vasoconstrictors: D.H.E. 45® (dihydroergotamine mesylate) Injection, USP 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 D.H.E. 45® (dihydroergotamine mesylate) Injection, USP. Sumatriptan and D.H.E. 45® (dihydroergotamine mesylate) Injection, USP 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 safe problem associated with the administration of D.H.E. 45® (dihydroergotamine mesylate) Injection, USP 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. Macrolide Antibiotics (e. g. erythromycin and troleandomycin): Agents of the ergot alkaloid class, of which D.H.E. 45® (dihydroergotamine mesylate) Injection, USP is a member, have been shown to interact with antibiotics of the macrolide class, resulting in increased plasma levels of unchanged alkaloids and peripheral vasoconstriction. Vasospastic reactions have been reported with therapeutic doses of ergotamine-containing drugs when co-administered with these antibiotics. SSRI's: Weakness hyperreflexia, and incoordination have been reported rarely when 5-HT1 agonists have been co-administered 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 D.H.E. 45® (dihydroergotamine mesylate) Injection, USP. Oral Contraceptives: The effect
of oral contraceptives
on the pharmacokinetics
of D.H.E. 45® (dihydroergotamine mesylate) Injection, USP has
not been studied.
D.H.E. 45® (dihydroergotamine mesylate) Injection, USP should only be used where a clear diagnosis of migraine headache has been established. Risk of Myocardial ischemia and/or Infarction and Other Adverse Cardiac Events D.H.E. 45® (dihydroergotamine mesylate) Injection USP should not be used by patients with documented ischemic or vasospastic coronary artery disease. ( See CONTRAINDICATIONS.) It is strongly recommended that D.H.E. 45® (dihydroergotamine mesylate) Injection USP 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 D.H.E. 45® (dihydroergotamine mesylate) Injection, USP should not be administered. (See CONTRAINDICATIONS) For patients with risk factors predictive of CAD who are determined to have a satisfactory cardiavascular evaluation, it is strongly recommended that administration of the first dose of D.H.E. 45® (dihydroergotamine mesylate) Injection, USP 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 D.H.E. 45® (dihydroergotamine mesylate) Injection, USP, in those patients with risk factors. It is recommended that patients who are intermittent long-term users of D.H.E. 45® (dihydroergotamine mesylate) Injection USP and who have or acquire risk factors predictive of CAD, as described above, undergo periodic interval cardiovascular evaluation as they continue to use D.H.E. 45® (dihydroergotamine mesylate) Injection, USP. The systematic approach described above is currently recommended as a method to identify patients in whom D.H.E. 45® (dihydroergotamine mesylate) Injection, USP may be used to treat migraine headaches with an acceptable margin of cardiovascular safety. Cardiac Events and Fatalities 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 D.H.E. 45® (dihydroergotamine mesylate) Injection, USP; and some have resulted in fatalities. In a number of cases, it appears possible that the cerebrovascular events were primary, the D.H.E. 45® (dihydroergotamine mesylate) Injection USP 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 D.H.E. 45® (dihydroergotamine mesylate) Injection, USP like other ergot alkaloids may cause vasospastic reactions other than coronary artery vasospasm. Myocardial, peripheral vascular and colonic ischemia have been reported with D.H.E. 45® (dihydroergotamine mesylate) Injection, USP. D.H.E. 45® (dihydroergotamine mesylate) Injection USP 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. D.H.E. 45® (dihydroergotamine mesylate) Injection, USP 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 injection. D.H.E. 45® (dihydroergotamine mesylate) Injection, USP is contraindicated in patients with uncontrolled hypertension. (See CONTRAINDICATIONS) An 18% increase in mean pulmonary artery pressure was seen following dosing with another 5-HT1 agonist in a study evaluating subjects undergoing cardiac catheterization.
General D.H.E. 45® (dihydroergotamine mesylate) Injection, USP may
cause coronary artery
vasospasm; patients who experience
signs or symptoms suggestive of angina
following its administration
should, therefore, be evaluated for the presence of CAD
or a predisposition
to variant angina
before receiving additional doses. Similarly, patients who experience
other symptoms or signs suggestive
of decreased arterial
flow, such as ischemic
bowel syndrome or Raynaud's
syndrome following
the use of any 5-HT agonist
are candidates for further evaluation. (See Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenesis: Assessment of the carcinogenic potential of dihydroergotamine mesylate in mice and rats is ongoing. 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: Impairment of fertility was not evaluated for D.H.E. 45® (dihydroergotamine mosylate) Injection, USP. There was no evidence of impairment of fertility in rats given intranasal doses of Migranal® Nasal Spray up to 1.6 mg/day (associated with mean plasma dihydroergotamine mesylate exposures [AUC] approximately 9 to 11 times those in humans receiving the MADE of 4 mg). Pregnancy Pregnancy Category X: See CONTRAINDICATIONS. Nursing Mothers Ergot drugs are known to inhibit prolactin. It is likely that D.H.E. 45® (dihydroergotamine mesylate) Injection, USP is excreted in human milk, but there are no data on the concentration of dihydroergotamine in human milk. It is known that ergotamine is excreted in breast milk and may cause vomiting, diarrhea, weak pulse, and unstable blood pressure in nursing infants. Because of the potential for these serious adverse events in nursing infants exposed to D.H.E. 45® (dihydroergotamine mesylate) Injection, USP, nursing should not be undertaken with the use of D.H.E. 45® (dihydroergotamine mesylate) Injection, USP. (See CONTRAINDICATIONS) Pediatric Use Safety and effectiveness
in pediatric patients
have not been established.
|
| |||