Almotriptan

Mechanism

Both drugs constrict blood vessels. Almotriptan stimulates serotonin receptors in artery walls, including the coronary arteries, and dihydroergotamine acts on the same receptors and also on adrenergic receptors. Triptans can cause coronary artery spasm and ergot drugs cause prolonged vasospasm, so their vasoconstrictor effects may add up. In a study of 12 healthy volunteers, oral almotriptan with ergotamine (the closest relative of dihydroergotamine) caused no extra vasospasm, but an additive effect is theoretically possible.

Symptoms

Coronary spasm shows as pressure, pain or heaviness in the chest, throat, neck or jaw, and can progress to myocardial infarction or dangerous arrhythmias. Spasm of other arteries can cause cold, pale or numb fingers, abdominal pain with bloody diarrhoea from bowel ischaemia, sudden loss of vision or signs of stroke. Dihydroergotamine can also raise blood pressure sharply.

Management

The combination is contraindicated (almotriptan ficha técnica, Spanish Agency of Medicines, AEMPS: ergotamine and its derivatives; almotriptan and dihydroergotamine labels, US Food and Drug Administration, FDA). Keep at least 24 hours between the two drugs, in either order (almotriptan and dihydroergotamine labels, FDA). The shorter 6-hour interval after almotriptan in the Spanish ficha técnica refers to ergotamine. For dihydroergotamine, keep 24 hours both ways (FDA labels). If chest, throat, neck or jaw pain or tightness appears after a dose, withhold further doses and assess the patient for cardiac ischaemia (almotriptan ficha técnica, AEMPS). If cold, pale fingers, abdominal pain with blood in the stool or vision loss appear after a dose, assess arterial blood flow (almotriptan label, FDA). Taking triptans and ergot drugs, alone or together, on 10 or more days a month can lead to medication overuse headache (dihydroergotamine label, FDA).

Mechanism

Both drugs constrict arteries. Almotriptan stimulates serotonin receptors in cranial vessels and constricts them. Like other triptans, it can very rarely cause coronary artery spasm. Ergotamine constricts blood vessels and can cause myocardial ischaemia, or rarely infarction, even in people with no known heart disease. Vasospasm after ergot drugs can be prolonged. In a study of 12 healthy volunteers, oral almotriptan with ergotamine caused no extra vasospasm, but the vasoconstrictor effects may in theory add up.

Symptoms

Coronary artery spasm causes chest pain, pressure or tightness, sometimes severe and spreading to the throat, neck or jaw, and can lead to myocardial infarction. Vasospasm from ergotamine causes numbness and tingling in the fingers and toes, headache and pain over the heart. With severe spasm, the limbs turn blue and their pulses disappear. Spasm of the intestinal arteries causes abdominal pain with bloody diarrhoea. Sudden vision loss and stroke have been reported after triptans. Both drugs can raise blood pressure.

Management

The almotriptan documents of the Spanish Agency of Medicines and Medical Devices (AEMPS) and the US Food and Drug Administration (FDA) contraindicate the combination. The Spanish summary of product characteristics (SmPC) for ergotamine with caffeine contraindicates all triptans (AEMPS). After ergotamine, wait at least 24 hours before taking almotriptan (almotriptan SmPC, AEMPS, and label, FDA). After almotriptan, the Spanish SmPC allows ergotamine after 6 hours, while the US label requires the same 24 hours (almotriptan label, FDA). If ergotamine has not stopped the attack, do not add a triptan for the same attack (ergotamine with caffeine SmPC, AEMPS). If chest pain or tightness appears after an almotriptan dose, withhold further doses and assess the patient for cardiac ischaemia (almotriptan SmPC, AEMPS). Stop ergotamine at once if numbness or tingling in the fingers, pain over the heart or other signs of vasospasm appear (ergotamine with caffeine SmPC, AEMPS). If abdominal pain with blood in the stool, white fingers or vision loss follow a dose, assess arterial blood flow (almotriptan label, FDA). Taking ergotamine, triptans or both on 10 or more days a month can cause medication overuse headache, with more frequent attacks (almotriptan label, FDA).

Mechanism

Almotriptan is CYP3A4 + CYP2D6 substrate. With phenelzine – fatal serotonin syndrome.

Symptoms

Agitation, tachycardia, hyperthermia, myoclonus, hyperreflexia within hours.

Management

Combination contraindicated. 14 days after MAOI withdrawal before starting triptan.

Mechanism

MAO-A inhibition + triptan – fatal serotonin syndrome.

Symptoms

Agitation, tachycardia, hyperthermia, myoclonus, hyperreflexia within hours.

Management

Combination contraindicated. 14 days after MAOI withdrawal before starting triptan.