Dihydroergocristine is an ergot alkaloid that has an partial agonist activity on dopaminergic and alpha-adrenergic receptors and antagonist activity on serotonin receptors. The drug was approved by FDA in combination with other alkaloids (dihydroergocornine, dihydro-alpha-ergocryptine and dihydro-beta-ergocryptine mesylate salts) under the name Hydergine for the treatment of dimentia and cerebrovascular insufficiency.

Nicergoline is a semisynthetic ergoline derivative that has been used as a cerebral vasodilator and in peripheral vascular disease. Nicergoline seems to have an action: (i) as an alpha1-adrenoceptor antagonist, it induces vasodilation and increases arterial blood flow; (ii) it enhances cholinergic and catecholaminergic neurotransmitter function; (iii) it inhibits platelet aggregation; (iv) it promotes metabolic activity, resulting in increased utilization of oxygen and glucose; and (v) it has neurotrophic and antioxidant properties. Nicergoline has been suggested to ameliorate cognitive deficits in cerebrovascular disease.

Ergoloid mesylates (USAN), co-dergocrine mesilate (BAN) or dihydroergotoxine mesylate, trade name Hydergine, is a mixture of the methanesulfonate salts of three dihydrogenated ergot alkaloids (dihydroergocristine, dihydroergocornine, and alpha- and beta-dihydroergocryptine). It was developed by Albert Hofmann (the inventor of LSD) for Sandoz (now part of Novartis). Ergoloid mesylates act centrally, decreasing vascular tone and slowing the heart rate, and acts peripherally to block alpha-receptors. One other possible mechanism is the effect of ergoloid mesylates on neuronal cell metabolism, resulting in improved oxygen uptake and cerebral metabolism, thereby normalizing depressed neurotransmitter levels. Ergoloid Mesylate may increase cerebral metabolism and blood flow. The role of this medication in the therapy of dementia is controversial. A recent controlled study in patients with Alzheimer's disease found that there was no advantage to the use of ergoloid mesylates compared to placebo, suggesting that ergoloid mesylates may lower scores on some cognitive and behavioral rating scales. Further study is needed to determine the risk-benefit profile of ergoloid mesylates in the treatment of dementia.