An adequate dose should be taken as soon as possible and not divided into half-hourly or hourly supplements. If the initial dose fails, subsequent doses usually fail also. A sub-nauseating dose, if possible, should be determined. The appropriate ergotamine dosage is best determined by titrating the patient s capacity to tolerate ergotamine during a headache-free period. If the clinician encounters a patient for the first time during a headache attack, it is a common practice to give 1 mg immediately and, if there is no evidence of improvement in 45 minutes, another 1-mg dose is given.
Rectal administration is more effective.
Ergotamine is also contraindicated in CAD and peripheral artery disease. It was also noted in early studies that despite the close similarities in chemical structure, DHE had minimal to no effects on peripheral arterial constriction compared to ergotamine. DHE is available as a parenteral preparation and as a nasal spray. Another advantage is that DHE does not result in physical dependence. Therefore, IM injection of 1 mg is preferable to the subcutaneous route.