Pharmacokinetics: Interactions

Pharmacokinetic interactions (increased blood levels of ergotamine) have been reported in patients treated orally with ergotamine and macrolide antibiotics (e.g., troleandomycin, clarithromycin, erythromycin), and in patients treated orally with ergotamine and protease inhibitors (e.g., ritonavir) presumably due to inhibition of cytochrome P450 3A metabolism of ergotamine (See CONTRAINDICATIONS). Ergotamine has also been shown to be an inhibitor of cytochrome P450 3A catalyzed reactions. No pharmacokinetic interactions involving other cytochrome P450 isoenzymes are known.

CYP 3A4 Inhibitors (e.g., Macrolide Antibiotics and Protease Inhibitors)

Coadministration of ergotamine with potent CYP 3A4 inhibitors such as protease inhibitors or macrolide antibiotics has been associated with serious adverse events; for this reason, these drugs should not be given concomitantly with ergotamine (See CONTRAINDICATIONS). While these reactions have not been reported with less potent CYP 3A4 inhibitors, there is a potential risk for serious toxicity including vasospasm when these drugs are used with ergotamine. Examples of less potent CYP 3A4 inhibitors include: saquinavir, nefazodone, fluconazole, fluoxetine, grapefruit juice, fluvoxamine, zileuton, metronidazole, 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 ergotamine.

Fibrotic Complications

There have been a few reports of patients on ergotamine tartrate and caffeine therapy developing retroperitoneal and/or pleuropulmonary fibrosis. There have also been rare reports of fibrotic thickening of the aortic, mitral, tricuspid, and/or pulmonary valves with long-term continuous use of ergotamine tartrate and caffeine. Ergomar® Sublingual Tablets should not be used for chronic daily administration (See DOSAGE AND ADMINISTRATION).

General

Although signs and symptoms of ergotism rarely develop even after long term intermittent use of the drug, care should be exercised to remain within the limits of recommended dosage. Ergotism is manifested by intense arterial vasoconstriction, producing signs and symptoms of peripheral vascular ischemia. Ergotamine induces vasoconstriction by a direct action on vascular smooth muscle. In chronic intoxication with ergot derivatives, headache, intermittent claudication, muscle pains, numbness, coldness and pallor of the digits may occur. If the condition is allowed to progress untreated, gangrene can result. While most cases of ergotism associated with ergotamine treatment result from frank overdosage, some cases have involved apparent hypersensitivity. There are few reports of ergotism among patients taking doses within the recommended limits or for brief periods of time. In rare instances, patients, particularly those who have used the medication indiscriminately over long periods of time, may display withdrawal symptoms consisting of rebound headache upon discontinuation of the drug.

Information for Patients

Patients should be advised that one Ergomar® Sublingual Tablet should be taken at the first sign of a migraine headache. No more than 2 tablets should be taken for any single migraine attack. No more than 5 tablets should be taken during any 7-day period. Administration of Ergomar® Sublingual Tablets should not exceed the dosing guidelines and should not be used for chronic daily administration (See DOSAGE AND ADMINISTRATION). Ergomar® Sublingual Tablets should be used only for migraine headaches. It is not effective for other types of headaches and it lacks analgesic properties. Patients should be advised to report to the physician immediately any of the following: numbness or tingling in the fingers and toes, muscle pain in the arms and legs, weakness in the legs, pain in the chest or temporary speeding or slowing of the heart rate, swelling or itching.

Drug Interactions

Pregnancy

Labor and Delivery

Ergomar® is contraindicated in pregnancy due to its oxytocic effect which is maximal in the third trimester. (See CONTRAINDICATIONS)

Nursing Mothers

Ergot drugs are known to inhibit prolactin but there are no reports of decreased lactation with Ergomar®. Ergotamine is excreted in breast milk and may cause symptoms of vomiting, diarrhea, weak pulse and unstable blood pressure in nursing infants. Because of the potential for serious adverse reactions in nursing infants from Ergomar®, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

Procedure

For best results, dosage should start at the first sign of an attack. Early Administration Gives Maximum Effectiveness. At the first sign of an attack or to relieve symptoms after onset of an attack, one 2 mg tablet is placed under the tongue. Another tablet should be taken at half-hour intervals thereafter, if necessary, but dosage must not exceed three tablets in any 24 hour period. Total weekly dosage should not exceed five tablets (10 mg) in any one week. Ergomar® Sublingual Tablets should not be used for chronic daily administration.

STORE AND DISPENSE

Store at 20°- 25°C (68° - 77°F) [see USP Controlled Room Temperature]; excursions permitted to 15° - 30°C (59° - 86°F). Protect from light and heat. Keep out of reach of children.