Patients with cognitive deficits associated with chronic cerebrovascular disorders may not respond to anti-dementia treatments in the same manner as can be observed in cases of Alzheimer's dementia. There is some evidence that CDP-choline provides modest but consistent improvement of memory and behaviour in these patients. These findings, however, are limited by the relatively short-term of clinical controlled observations which in all studies but one lasted for no more than three months. Subjective evaluations of these patients as given by their doctors were consistently positive and no noticeable side effects were evidenced in the various studies over the years.
There was some evidence that CDP-choline has a positive effect on memory and behaviour in at least the short to medium term. The evidence of benefit from global impression was stronger, but is still limited by the duration of the studies. Further research with CDP-choline should focus on longer term studies in subjects who have been diagnosed with currently accepted standardised criteria, especially Vascular Mild Cognitive Impairment (VaMCI) or vascular dementia.
CDP-choline (cytidine 5'-diphosphocholine) is a precursor essential for the synthesis of phosphatidylcholine, one of the cell membrane components that is degraded during cerebral ischaemia to free fatty acids and free radicals. Animal studies suggest that CDP-choline may protect cell membranes by accelerating resynthesis of phospholipids. CDP-choline may also attenuate the progression of ischaemic cell damage by suppressing the release of free fatty acids. CDP-choline is the endogenous compound normally produced by the organism. When the same substance is introduced as a drug it can be called citicoline.
CDP-choline is mainly used in the treatment of disorders of a cerebrovascular nature. The many years of its presence in the clinical field have caused an evolution in dosage, method of administration, and selection criteria of patients to whom the treatments were given. Modalities of the clinical studies, including length of observation, severity of disturbance, and methodology of evaluation of the results were also heterogeneous. In spite of uncertainties about its efficacy due to these complexities, CDP-choline is a frequently prescribed drug for cognitive impairment in several European countries, especially when the clinical picture is predominantly one of cerebrovascular disease, hence the need for this review.
Due to its effects on the adrenergic and dopaminergic activity of the CNS, CDP-choline has also been used as an adjuvant in the treatment of Parkinson's disease.
To assess the efficacy of CDP-choline (cytidinediphosphocholine) in the treatment of cognitive, emotional, and behavioural deficits associated with chronic cerebral disorders in the elderly.
The trials were identified from a last updated search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group on 22 April 2004 using the terms CDP-choline, CDP, citicoline, cytidine diphosphate choline or diphosphocholine. The Register contains records from all major health-care databases and many ongoing trials databases and is updated regularly.
All relevant unconfounded, double-blind, placebo-controlled, randomized trials of CDP-choline for cognitive impairment due to chronic cerebral disorders were considered for inclusion in the review.
Two reviewers independently reviewed the included studies, extracted the data, and pooled it when appropriate and possible. The pooled odd ratios (95% Confidence Interval (CI)) or the average differences (95% CI) were estimated. No intention-to-treat data were available from the studies included.
Fourteen studies were included in this review. Some of the included studies did not present numerical data suitable for analysis. Description of participants varied over the years and by type of disorders and severity, and ranged from aged individuals with subjective memory disorders to patients with Vascular Cognitive Impairment (mild to moderate), Vascular Dementia or Senile Dementia (mild to moderate). Seven of the included studies observed the subjects for a period between 20 to 30 days, one study was of 6 weeks duration, four studies used periods extending over 2 and 3 months, one study observed continuous administration over 3 months and one study was prolonged, with 12 months of observation. The studies were heterogeneous in dose, modalities of administration, inclusion criteria for subjects, and outcome measures. Results were reported for the domains of attention, memory testing, behavioural rating scales, global clinical impression and tolerability. There was no evidence of a beneficial effect of CDP-choline on attention. There was evidence of benefit of CDP-choline on memory function and behaviour. The drug was well tolerated.