IngredientsGalantamine possesses a quite complicated chemical structure with three chiral centers; its IUPAC name is (4aS,6R,8aS)-5,6,9,10,11,12-hexahydro-3-methoxy-11-methyl-4aH-[1]benzofuro[3a,3,2-ef][2]benzazepin-6-ol. It is also termed galanthamine, belongs to the alkaloid class, and is a derivative of phenanthrene. The empirical formula is C₁₇H₂₁NO₃, with a molecular weight of 287.35 g/mol. The melting point of galantamine is 269–270 °C (as the HBr salt), and its solubility in water is 10 mg/mL (HBr salt). Galantamine belongs to the isoquinoline alkaloid family. It is a benzazepine derived from norbelladine. In its pure form, galantamine is a white powder. The atomic-resolution three-dimensional structure of the complex of galantamine and its target, acetylcholinesterase, was determined by X-ray crystallography in 1999 (PDB code: 1DX6).
Galantamine is an alkaloid extracted from the bulbs and flowers of Galanthus nivalis (common snowdrop), Galanthus caucasicus (Caucasian snowdrop), Galanthus woronowii (Voronov's snowdrop), and other members of the family Amaryllidaceae, such as Narcissus (daffodil), Leucojum aestivum (snowflake), and Lycoris, including Lycoris radiata (red spider lily). Galantamine is found in various plant sources, mainly from the genera Amaryllis, Lycoris, Hippeastrum, Ungernia, Leucojum, Zephyranthes, Narcissus, Galanthus, Hymenocallis, and Haemanthus. Narcissus species contain galantamine in varying amounts, from trace quantities to as much as 2.5% of dry weight. Since the alkaloid occurs in botanical sources that contain only approximately 0.1% galantamine by weight, extraction yields from these plants are extremely low. Today, galantamine is produced commercially primarily from Leucojum aestivum, known as the common snowflake, commonly found in Europe and North America. On an industrial scale, galantamine is also extracted from the bulbs of daffodils, and it can additionally be manufactured by total chemical synthesis.
Galantamine is available generically and under the brand name Razadyne in tablets of 4, 8, and 12 mg and as extended-release capsules of 8, 16, and 24 mg, and also as an oral solution (4 mg/mL). In Bulgaria, tablet forms of 5 mg and 10 mg and ampoule forms of 2.5 mg/1 mL, 5 mg/1 mL, and 10 mg/1 mL are available. The compound is marketed under a variety of brand names internationally, including Reminyl® and Nivalin®. In July 2024, the FDA approved benzgalantamine (Zunveyl), a prodrug derivative of galantamine, to treat mild-to-moderate Alzheimer's disease.
Galanthus species are native to many parts of Europe, including Bulgaria, the eastern parts of Turkey, and the Caucasus mountain range. Plaitakis and Duvoisin (1983) hypothesized that Homer's "moly" was the snowdrop, Galanthus nivalis. In his epic poem the Odyssey, Homer described "moly" and its use by Odysseus as an antidote against Circe's poisonous drugs. This description of "moly" as an antidote in Homer's Odyssey may thus represent the oldest recorded use of Galanthus, though the evidence is scanty. It has been proposed that the drugs Circe used were an extract from Datura stramonium (jimsonweed), which causes memory loss and delirium. This would provide a rationale for the snowdrop's reputed use as an antidote, since Datura stramonium is anticholinergic while galantamine is an acetylcholinesterase inhibitor.
The history of galantamine's development traces aspects from little-known observational studies in the Caucasus Mountains (Southern Russia) to the use of this drug in Eastern European countries, particularly Bulgaria, in the treatment of poliomyelitis, and ultimately to its introduction onto Western markets for Alzheimer's disease. The alkaloid galantamine was first extracted from the snowdrop in the early 1950s after a Bulgarian pharmacologist observed remote villagers rubbing their foreheads with the plant's leaves and bulbs. It seems likely that ethnomedicine prompted these formal scientific investigations, although hard evidence is lacking. Previously hidden uses of snowdrops in traditional (folk) medicine have since been described.
In 1947, a Soviet journal reported the presence of previously unknown alkaloids in the common snowdrop, Galanthus nivalis. A few years later, the same team isolated and characterized galantamine from the closely related Galanthus woronowii. Japanese researchers appear to have independently isolated the same alkaloid from the red spider lily (Lycoris radiata), calling it lycoremine. Galantamine was isolated for the first time from bulbs of Galanthus nivalis by the Bulgarian chemist D. Paskov and his team in 1956. The active ingredient was extracted, identified, and studied, particularly in relation to its acetylcholinesterase (AChE)-inhibiting properties. The first industrial process was developed in 1959. In 1960, the correct structure of galantamine as an amino acid-derived tetracycle was established by Shigeru Kobayashi and Sir Derek Barton.
Galantamine was first officially approved for use as a drug in Bulgaria in 1958. Prior to its use in Alzheimer's disease, galantamine was available in Eastern Europe as a curare-reversal agent in anesthesia and as a treatment for such neurologic conditions as myasthenia gravis. Galantamine was used in neurology for the treatment of paresis of the facial nerves and other mono- and polyneuropathies, residual paraplegia after poliomyelitis or brain and/or spinal cord injuries, as well as myasthenia gravis. The tablet and ampoule forms used in Bulgaria were applied to conditions such as polyradiculoneuritis, radiculoneuritis, neuritis, polyneuritis, and polyneuropathies, as well as conditions associated with damage to the anterior horns of the spinal cord (after poliomyelitis, myelitis, and spinal muscular atrophy), cerebral palsy, stroke sequelae, infantile cerebral palsy, and neuromuscular synapse disorders. Galantamine hydrobromide (Nivalin), an alkaloid from the bulbs of snowdrops, is widely used in Bulgaria as an antagonist to non-depolarizing muscle relaxants.
Characterized in the early 1950s in Bulgaria, galantamine saw limited use for paralytic and neuropathic conditions until the cholinergic hypothesis of Alzheimer's disease opened entirely new perspectives for its utility. Although constricted supplies at extremely high prices and a fragmented patent situation made its repurposing challenging, galantamine was globally launched as an Alzheimer's disease drug in 2000.
Galantamine itself is the principal and pharmacologically active alkaloid. It is a tertiary alkaloid characterized in the early 1950s and extracted from plant sources such as Galanthus nivalis. Structurally, it comprises a fusion between a methoxy-substituted benzene ring linked to a hydrogenated and methylated azepine ring along with a hydroxylated benzofuran group. The compound's biological potency derives not from a single mechanism but from a well-characterized dual action on the cholinergic system.
Galantamine is a cholinesterase inhibitor with a dual mechanism of action. It is a reversible inhibitor of acetylcholinesterase and enhances the intrinsic action of acetylcholine on nicotinic receptors, leading to increased cholinergic neurotransmission in the CNS. By inhibiting acetylcholinesterase, it increases the concentration and thereby the action of acetylcholine in certain parts of the brain. Deficiency of acetylcholine caused by selective loss of cholinergic neurons in the cerebral cortex, nucleus basalis, and hippocampus is a pathologic feature of Alzheimer's disease associated with cognitive deficits. The effects of galantamine may therefore diminish as the Alzheimer's disease process advances and fewer cholinergic neurons remain functioning.
Since galantamine is a rather weak acetylcholinesterase inhibitor but has additional allosteric potentiating effects at nicotinic receptors, it affects not only cholinergic transmission but also other neurotransmitter systems such as monoamines, glutamate, and γ-aminobutyric acid (GABA) through its allosteric mechanism. Galantamine's effects on nicotinic acetylcholine receptors (nAChRs) and complementary acetylcholinesterase inhibition together make up this dual mechanism of action. Animal model studies suggest that not only the nicotinic receptor-modulating properties but also muscarinic receptor activation contribute to the antipsychotic effect and improvement of cognitive dysfunction by galantamine.
The inflammatory reflex is also activated by galantamine, a centrally acting acetylcholinesterase inhibitor. Galantamine suppresses serum TNF and other proinflammatory cytokine levels and improves survival in lethal endotoxin-induced inflammation. These anti-inflammatory effects of galantamine are mediated through brain muscarinic acetylcholine receptor signaling and vagus nerve activity. It has been proposed that brain cholinergic deficiency, which may be caused by neuroinflammation, drives further inflammation and neuroinflammation, and that administering galantamine and other centrally acting AChE inhibitors could interrupt this vicious cycle.
Following oral administration, galantamine is rapidly absorbed and reaches peak plasma concentration (Cmax) in approximately one hour for immediate-release (IR) tablets and four hours for extended-release (ER) capsules. Food has no clinically important effects on the absorption of galantamine. Galantamine displays dose-proportional pharmacokinetics over a dose range of 8–32 mg and 8–24 mg for IR and ER formulations, respectively. The elimination half-life of galantamine is approximately 7–8 hours. Galantamine has low protein binding (28.3–33.8%) and has an apparent steady-state volume of distribution of 193 L. Approximately 20–25% of the administered dose is excreted unchanged in urine. No clinically significant effects of age, gender, or race have been observed on galantamine pharmacokinetics.
Galantamine is used clinically for treating early-stage Alzheimer's disease and memory impairments, although it has had limited success with the more advanced condition of dementia. It and its derivatives were approved by the US Food and Drug Administration in 2001.
Cochrane Review Evidence (2024): The 2024 Cochrane systematic review included double-blind, parallel-group, randomised controlled trials comparing oral galantamine with placebo for a treatment duration exceeding four weeks in people with dementia due to Alzheimer's disease or with mild cognitive impairment. After 6 months of treatment, participants with mild to moderate Alzheimer's disease who received galantamine had better memory, ability to perform self-care activities, and behaviour than those who received placebo. Importantly, the memory improvements observed were considered clinically meaningful according to expert standards. This same group of participants probably had better overall improvement than those who received placebo. The review found very strong evidence of lower ADAS-cog scores (Alzheimer's Disease Assessment Scale – cognitive subscale) in galantamine groups compared to placebo groups.
Short-term, double-blind, placebo-controlled studies have shown that treatment with galantamine produces small improvements on cognitive tests and global measures of change in selected patients with mild to moderately severe Alzheimer's disease. A dose of 16–24 mg/day appears to be the most efficacious, and is the licensed maintenance dose range in most territories.
The Cochrane evidence shows consistent positive effects for galantamine for trials of three to six months' duration. Although there was not a statistically significant dose-response effect, doses above 8 mg/day were, for the most part, consistently statistically significant. Although death rates were generally low, participants in the galantamine groups had a reduced risk of death compared to those in the placebo groups.
Limitations: Among the currently approved drugs for the pharmacotherapy of Alzheimer's disease, galantamine represents one of three reversible inhibitors (alongside donepezil and rivastigmine) that are commonly applied in neurodegenerative disorder treatment. Despite extensive testing of galantamine, as of 2014 its regulatory approval had not been expanded beyond its original indication of mild to moderate Alzheimer's disease. The modest effect sizes seen in randomized controlled trials have created continuing debate about the cost-effectiveness of cholinesterase inhibitor therapies.
In people with mild cognitive impairment, galantamine, compared to placebo, may make little to no difference in improving memory or the ability to perform self-care activities. There is no evidence to support the use of galantamine in people with mild cognitive impairment. As with other cholinesterase inhibitors, galantamine may not be effective for treating mild cognitive impairment. The evidence for MCI is therefore weak, and galantamine is not approved for this indication.
Galantamine is indicated for the treatment of mild to moderate vascular dementia as well as Alzheimer's disease in certain jurisdictions. A randomized trial by Erkinjuntti et al. (2002), published in The Lancet, studied the efficacy of galantamine in probable vascular dementia and Alzheimer's disease combined with cerebrovascular disease. Clinical investigations of galantamine have gone beyond Alzheimer's disease to study other types of dementia, mild cognitive impairment, and cognitive impairment in schizophrenia and bipolar disorder. Overall, evidence in vascular dementia remains more limited and less well-established than in Alzheimer's disease.
A clinical trial revealed the anti-inflammatory and beneficial metabolic effects of galantamine in patients with metabolic syndrome. In this trial, treatment of 30 patients with clinically approved doses of galantamine for 8 weeks, compared with 30 placebo-treated patients, significantly alleviated plasma levels of TNF and leptin (pro-inflammatory) and increased plasma levels of IL-10 and adiponectin (anti-inflammatory). Galantamine treatment also ameliorated oxidative stress in patients with metabolic syndrome. These effects were accompanied by lower insulin levels and improved insulin resistance in galantamine-treated patients, as well as modulation of the autonomic neural regulation toward vagus nerve predominance. In a separate study in obese African-American women, 16 mg of galantamine significantly inhibited lipid-induced increases in oxidative stress markers (F2-isoprostanes), and decreased IL-6 and TNFα levels compared with placebo. These are promising early-phase clinical findings but are based on small trials and require replication in larger, controlled studies.
Several lines of evidence suggest that cholinergic deficits may contribute to the pathophysiology of psychiatric disorders as well as Alzheimer's disease. There is growing clinical evidence that galantamine, currently used for the treatment of Alzheimer's disease, may improve cognitive dysfunction and psychiatric illness in schizophrenia, major depression, bipolar disorder, and alcohol abuse. Galantamine is still being actively evaluated as a cognitive enhancer in bipolar disorder and schizophrenia, and as an aid to end nicotine or cocaine dependence. However, evidence in these areas is predominantly derived from small trials and is considered preliminary. No regulatory approval in these indications has been granted.
Galantamine's safety and efficacy have been evaluated in different patient populations including Alzheimer's disease, mild cognitive impairment, Parkinson's disease, attention deficit hyperactivity disorder (ADHD), chronic fatigue syndrome, schizophrenia, and alcohol dependence. Conditions investigated include vascular dementia, tardive dyskinesia, ADHD, post-traumatic headache, postoperative delirium, depression, Tourette's syndrome, bipolar disorder, cognition in schizophrenia, and stroke. Development attempts for chronic fatigue and fibromyalgia have been discontinued. The anti-inflammatory and disease-alleviating efficacy of galantamine has been demonstrated in animals with endotoxemia, sepsis, inflammatory bowel disease, and post-operative cognitive deterioration, among other disorders. Preclinical evidence in these newer areas is accumulating, but robust clinical trial data remain limited or absent.
The primary therapeutic target of galantamine is the central nervous system. Interest in galantamine's potential use in Alzheimer's disease was generated on the basis of its ability to penetrate the blood-brain barrier and affect cholinergic transmission. Galantamine binds allosterically with nicotinic acetylcholine receptors and may potentiate the action of agonists such as acetylcholine at these receptors. Deficiency of acetylcholine caused by selective loss of cholinergic neurons in the cerebral cortex, nucleus basalis, and hippocampus is a pathologic feature of Alzheimer's disease associated with cognitive deficits.
Galantamine also works as a weak competitive and reversible cholinesterase inhibitor in all areas of the body. As an acetylcholinesterase inhibitor, galantamine is likely to prolong the neuromuscular blocking effects of succinylcholine-type and other similar neuromuscular blocking agents by delaying the cholinesterase-mediated hydrolytic metabolism of these drugs during anesthesia. Historically, this property was exploited as a reversal agent for curare-type muscle relaxants in Eastern European surgical practice.
Galantamine lowers indices of colonic inflammation and alleviates disease severity in experimental inflammatory bowel disease. Its capacity to activate the cholinergic anti-inflammatory pathway via the vagus nerve represents a mechanistic basis for its effects on systemic inflammation and metabolic syndrome, an area of active translational research.
Galantamine treatment alters heart rate variability (HRV) frequency components and significantly lowers LF/HF ratios, indicating a shift toward parasympathetic (vagal) dominance. This effect has implications for cardiovascular autonomic regulation in metabolic disease, though long-term cardiovascular outcomes data are lacking.
Galantamine, as a cholinomimetic agent, may cause or worsen bladder outflow obstruction, and its use requires caution in patients with prostatic hypertrophy.
For immediate-release tablets, a dosage of 16 to 32 mg daily has demonstrated effectiveness in controlled clinical trials for Alzheimer's dementia. However, the 32 mg daily dose has been reported to be less tolerable than lower doses. Therefore, the recommended dosage is 16 to 24 mg daily.
The usual maintenance dose is 16 to 24 mg daily in two divided doses or once daily using the extended-release forms. A slow titration strategy is clinically important for tolerability: eligible patients in clinical trials typically receive an initial galantamine dose of 8 mg/day, escalated over 5–8 weeks to maintenance doses of 16 or 24 mg/day.
In some research contexts (e.g., for alcohol dependence), initial doses of 8 mg escalating to a maximum of 16 mg/day have been used — lower than the typical maintenance dose of 16–24 mg/day used in Alzheimer's disease trials.
Common adverse events occurring in more than 5% of participants in clinical trials include weight loss (5%–7%), diarrhea (6%–12%), loss of appetite (7%–9%), nausea (13%–24%), vomiting (6%–13%), dizziness (9%), and headache (8%).
For the 8 mg/day dose, none of the adverse events was statistically significantly more frequent than with placebo treatment. At 16 mg/day, nausea, vomiting, and diarrhea were statistically significantly more frequent than with placebo.
Galantamine displays dose-proportional pharmacokinetics over a dose range of 8–32 mg and 8–24 mg for IR and ER formulations, respectively.
Common side effects include nausea, vomiting, diarrhea, abdominal pain, dizziness, fatigue, insomnia, vivid dreams, anxiety, restlessness, blurred vision, dry mouth, and pruritus — symptoms common to cholinergic stimulation. Uncommon but potentially severe adverse events include bradycardia and atrioventricular block, urinary retention, gastrointestinal bleeding, and hypersensitivity reactions.
Among 2,045 patients with Alzheimer's disease treated with galantamine or placebo for up to 2 years, symptoms of nausea, vomiting, and fatigue were slightly more frequent with galantamine than placebo, but serious adverse events were similar in the two groups, and no clinically meaningful changes were observed in laboratory tests.
A gradual titration over more than three months may enable long-term tolerability in some people.
Less common adverse events include bradyarrhythmia (approximately 2%), cardiac dysrhythmia (infrequent), heart failure (infrequent), esophageal perforation (rare), gastrointestinal hemorrhage, rectal hemorrhage (infrequent), and death (very rare). Antihypertensive agents such as β-blockers (acebutolol), α- and β-blockers (carvedilol), and calcium channel blockers (diltiazem) may also cause atrioventricular block and bradycardia. When galantamine is used along with these drugs, there is potential for an additive bradycardic effect. ACE inhibitors such as ramipril do not interact with galantamine and can be safely co-administered.
The exposures to galantamine in patients with moderate and severe renal impairment are 37% and 67% higher, respectively, than in healthy subjects, whereas the exposure to galantamine is approximately 30% higher in patients with moderate hepatic impairment. Use is not recommended in patients with severe hepatic impairment (Child-Pugh score of 10–15). Dosage modification is recommended in patients with moderate hepatic impairment. Use is not recommended in patients with severe renal impairment (CrCl <9 mL/min). Dosage modification is recommended in patients with moderate renal impairment.
Co-administration of galantamine with ketoconazole (a strong CYP3A4 inhibitor) or paroxetine (a strong CYP2D6 inhibitor) leads to a 30% and 40% increase, respectively, in galantamine exposure compared to galantamine given alone. Galantamine is metabolized by CYP3A4 and CYP2D6, so there is likely to be inhibition of galantamine clearance by potent inhibitors of these enzymes, such as ritonavir and cobicistat. Population pharmacokinetic analysis has indicated that there is a 25% decrease in median clearance in CYP2D6 poor metabolizers compared to extensive metabolizers; however, dosage adjustment is not considered necessary in patients identified as poor metabolizers.
As an acetylcholinesterase inhibitor, galantamine is likely to prolong the neuromuscular blocking effects of succinylcholine-type and other similar neuromuscular blocking agents by delaying their cholinesterase-mediated hydrolytic metabolism during anesthesia. This interaction is clinically relevant in surgical settings and should be communicated to anesthesiologists prior to any procedure.
Galantamine is contraindicated in patients with known hypersensitivity to galantamine or its formulation components. The adverse effect profile of galantamine includes potential for allergic reactions, including hives, swelling of the face or throat, and skin rash. Use may also cause chest pain, bloody urine, stomach bleeding, and liver injury, among other side effects.
Health conditions that Galantamine may help support.
Body systems that Galantamine may help support.
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