Palmitoylethanolamide and acetyl-L-carnitine act synergistically with duloxetine and pregabalin in fibromyalgia: results of a randomised controlled study.

OBJECTIVES: Fibromyalgia (FM) is characterised by a form of debilitating pain that is unresponsive to standard analgesics. The aim of this study was to evaluate the efficacy of supplementing ongoing pregabalin (PGB) and duloxetine (DLX) treatment with palmitoylethanolamide (PEA) and acetyl-L-carnitine (ALC) for 24 weeks in FM patients. METHODS: After undergoing three months of stable treatment with DLX+PGB, FM patients were randomised to continue the same treatment (Group 1) or to add PEA 600 mg b.i.d + ALC 500 mg b.i.d. (Group 2) for a further 12 weeks. Every two weeks throughout the study, cumulative disease severity was estimated using the Widespread Pain Index (WPI) as the primary outcome measure; the secondary outcomes were the fortnightly scores of the patient-completed revised Fibromyalgia Impact Questionnaire (FIQR) and the modified Fibromyalgia Assessment Status (FASmod) questionnaire. All three measures were expressed as time-integrated area under the curve (AUC) values. RESULTS: One hundred and thirty (91.5%) of the initial 142 FM patients completed the study: 68 patients in Group 1 and 62 in Group 2. Twenty-four weeks after randomisation, the Group 2 patients showed additional significant improvements in all three outcome measures. Although there was some fluctuation in both groups during the study period, the AUC values of the WPI scores steadily decreased in Group 2 (p=0.048), which also showed better outcomes in terms of the AUC values of the FIQR (p=0.033) and FASmod scores (p=0.017). CONCLUSIONS: This is the first randomised controlled study demonstrating the effectiveness of the adding on therapy of PEA+ALC to DLX+PGB in FM patients.

Acetyl-L-carnitine for the treatment of diabetic peripheral neuropathy.

BACKGROUND: Diabetic peripheral neuropathy (DPN) is a common and severe complication that affects 50% of people with diabetes. Painful DPN is reported to occur in 16% to 24% of people with diabetes. A complete and comprehensive management strategy for the prevention and treatment of DPN, whether painful or not, has not yet been defined.Research into treatment for DPN has been characterised by a series of failed clinical trials, with few noteworthy advances. Strategies that support peripheral nerve regeneration and restore neurological function in people with painful or painless DPN are needed. The amino acid acetyl-L-carnitine (ALC) plays a role in the transfer of long-chain fatty acids into mitochondria for ß-oxidation. ALC supplementation also induces neuroprotective and neurotrophic effects in the peripheral nervous system. Therefore, ALC supplementation targets several mechanisms relevant to potential nerve repair and regeneration, and could have clinical therapeutic potential. There is a need for a systematic review of the evidence from clinical trials. OBJECTIVES: To assess the effects of ALC for the treatment of DPN. SEARCH METHODS: On 2 July 2018, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform. We checked references, searched citations, and contacted study authors to identify additional studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs of ALC compared with placebo, other therapy, or no intervention in the treatment of DPN. Participants could be of any sex and age, and have type 1 or type 2 diabetes mellitus, of any severity, with painful or painless DPN. We accepted any definition of minimum criteria for DPN, in accordance with the Toronto Consensus. We imposed no language restriction.Pain was the primary outcome, measured as the proportion of participants with at least 30% (moderate) or 50% (substantial) decrease in pain over baseline, or as the score on a visual analogue scale (VAS) or Likert scale for pain. DATA COLLECTION AND ANALYSIS: We followed standard Cochrane methods. MAIN RESULTS: We included four studies with 907 participants, which were reported in three publications. Three trials studied ALC versus placebo (675 participants); in one trial the dose of ALC was 2000 mg/day, and in the other two trials, it was 1500 mg/day or 3000 mg/day. The fourth trial studied ALC 1500 mg/day versus methylcobalamin 1.5 mg/day (232 participants). The risk of bias was high in both trials of different ALC doses and low in the other two trials.No included trial measured the proportion of participants with at least moderate (30%) or substantial (50%) pain relief. ALC reduced pain more than placebo, measured on a 0- to 100-mm VAS (MD -9.16, 95% CI -16.76 to -1.57; three studies; 540 participants; P = 0.02; I² = 56%; random-effects; very low-certainty evidence; a higher score indicating more pain). At doses of 1500 mg/day or less, the VAS score after ALC treatment was little different from placebo (MD -0.05, 95% CI -10.00 to 9.89; two studies; 159 participants; P = 0.99; I² = 0%), but at doses greater than 1500 mg/day, ALC reduced pain more than placebo (MD -14.93, 95% CI -19.16 to -10.70; three studies; 381 participants; P < 0.00001; I² = 0%). This subgroup analysis should be viewed with caution as the evidence was even less certain than the overall analysis, which was already of very low certainty.Two placebo-controlled studies reported that vibration perception improved after 12 months. We graded this evidence as very low certainty, due to inconsistency and a high risk of bias, as the trial authors did not provide any numerical data. The placebo-controlled studies did not measure functional impairment and disability scores. No study used validated symptom scales. One study performed sensory testing, but the evidence was very uncertain.The fourth included study compared ALC with methylcobalamin, but did not report effects on pain. There was a reduction from baseline to 24 weeks in functional impairment and disability, based on the change in mean Neuropathy Disability Score (NDS; scale from zero to 10), but there was no important difference between the ALC group (mean score 1.66 ± 1.90) and the methylcobalamin group (mean score 1.35 ± 1.65) groups (P = 0.23; low-certainty evidence).One placebo-controlled study reported that six of 147 participants in the ALC > 1500 mg/day group (4.1%) and two of 147 participants in the placebo group (1.4%) discontinued treatment because of adverse events (headache, facial paraesthesia, and gastrointestinal disorders) (P = 0.17). The other two placebo-controlled studies reported no dropouts due to adverse events, and more pain, paraesthesia, and hyperaesthesias in the placebo group than the 3000 mg/day ALC group, but provided no numerical data. The overall certainty of adverse event evidence for the comparison of ALC versus placebo was low.The study comparing ALC with methylcobalamin reported that 34/117 participants (29.1%) experienced adverse events in the ALC group versus 33/115 (28.7%) in the methylcobalamin group (P = 0.95). Nine participants discontinued treatment due to adverse events (ALC: 4 participants, methylcobalamin: 5 participants), which were most commonly gastrointestinal symptoms. The certainty of the adverse event evidence for ALC versus methylcobalamin was low.Two studies were funded by the manufacturer of ALC and the other two studies had at least one co-author who was a consultant for an ALC manufacturer. AUTHORS' CONCLUSIONS: We are very uncertain whether ALC causes a reduction in pain after 6 to 12 months' treatment in people with DPN, when compared with placebo, as the evidence is sparse and of low certainty. Data on functional and sensory impairment and symptoms are lacking, or of very low certainty. The evidence on adverse events is too uncertain to make any judgements on safety.

Acetyl-L-Carnitine Supplementation and the Treatment of Depressive Symptoms: A Systematic Review and Meta-Analysis.

OBJECTIVE: Deficiency of acetyl-L-carnitine (ALC) seems to play a role in the risk of developing depression, indicating a dysregulation of fatty acid transport across the inner membrane of mitochondria. However, data about ALC supplementation in humans are limited. We thus conducted a systematic review and meta-analysis investigating the effect of ALC on depressive symptoms across randomized controlled trials (RCTs). METHODS: A literature search in major databases, without language restriction, was undertaken from inception until 30 December 2016. Eligible studies were RCTs of ALC alone or in combination with antidepressant medications, with a control group taking placebo/no intervention or antidepressants. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) were used for summarizing outcomes with a random-effect model. RESULTS: Twelve RCTs (11 of which were ALC monotherapy) with a total of 791 participants (mean age = 54 years, % female = 65%) were included. Pooled data across nine RCTs (231 treated with ALC versus 216 treated with placebo and 20 no intervention) showed that ALC significantly reduced depressive symptoms (SMD = -1.10, 95% CI = -1.65 to -0.56, I = 86%). In three RCTs comparing ALC versus antidepressants (162 for each group), ALC demonstrated similar effectiveness compared with established antidepressants in reducing depressive symptoms (SMD = 0.06, 95% CI = -0.22 to 0.34, I = 31%). In these latter RCTs, the incidence of adverse effects was significantly lower in the ALC group than in the antidepressant group. Subgroup analyses suggested that ALC was most efficacious in older adults. CONCLUSIONS: ALC supplementation significantly decreases depressive symptoms compared with placebo/no intervention, while offering a comparable effect with that of established antidepressant agents with fewer adverse effects. Future large scale trials are required to confirm/refute these findings.

Mania associated with self-prescribed acetyl-l-carnitine in a man with bipolar I disorder.

OBJECTIVE: Complementary medicines are readily available and becoming increasingly popular. Acetyl-l-carnitine (ALC) is widely recognised as a safe dietary supplement to aid weight loss. We present the case of a patient who had a relapse of mania in the context of ALC use for weight loss over a two week period, on the background of bipolar I disorder previously in remission. The patient's symptoms resolved a few days after ALC was ceased. CONCLUSIONS: Given the high rates of obesity among people with mental illness, it is possible ALC may be utilised in the hope of aiding weight loss. This case highlights the importance of psychiatrists maintaining open communication with their patients about use of complementary medicines, and the risks and benefits of their use.

Acetyl-L-carnitine (ALCAR) to enhance nerve regeneration in carpal tunnel syndrome: study protocol for a randomized, placebo-controlled trial.

BACKGROUND: Carpal tunnel syndrome (CTS) is the most common form of peripheral nerve injury, affecting approximately 3 % of the population. While surgery is effective in mild and moderate cases, nerve and functional recovery are often not complete in severe cases. Therefore, there is a need for adjuvant methods to improve nerve regeneration in those cases. Acetyl-L-carnitine (ALCAR) is involved in lipid transport, vital for mitochondrial function. Although it has been shown to be effective in various forms of neuropathies, it has not been used in traumatic or compressive peripheral nerve injury. METHODS: In this pilot study we will utilize a double-blind, randomized, placebo-controlled design. Inclusion criteria will include adult patients with severe CTS. This will be confirmed by nerve conduction studies and motor unit number estimation (MUNE). Only those with severe motor unit loss in the thenar muscles (2 standard deviations [SD] below the mean for the age group) will be included. Eligible patients will be randomized to receive 3,000 mg/day of ALCAR orally or placebo following carpal tunnel release surgery for 2 months. The primary outcome will be MUNE with supplementary secondary outcome measures that include: 1) two-point discrimination; 2) Semmes-Weinstein monofilaments for pressure sensitivity; 3) cold and pain threshold for small fiber function; 4) Boston self-assessment Carpal Tunnel Questionnaire and 5) Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire for symptom severity; and 6) Purdue Pegboard Test for hand functional performance. To follow post treatment recovery and monitor safety, patients will be seen at 3 months, 6 months and 1 year. The outcome measures will be analyzed using two-way ANOVA, with treatment assignment and time points being the independent factors. If significant associations are detected, a post hoc analysis will be completed. We aim to recruit ten patients into each of the two groups. Data from this pilot will provide the basis for power calculation for a full-scale trial. DISCUSSION: ALCAR is a physiologic peptide crucial for fatty acid transport. ALCAR has been shown to be effective in neuroprotection in the central nervous system and increase peripheral nerve regeneration. This has been applied clinically to various systemic peripheral neuropathies including diabetic neuropathy, antiretroviral toxic neuropathy, and chemotherapy-induced peripheral neuropathy. While animal evidence exists for the benefit of ALCAR in compression neuropathy, there have been no human studies to date. This trial will represent the first use of ALCAR in peripheral nerve injury/compression neuropathy. TRIAL REGISTRATION: NCT02141035 ; 20 April 2015.

Randomized double-blind placebo-controlled trial of acetyl-L-carnitine for the prevention of taxane-induced neuropathy in women undergoing adjuvant breast cancer therapy.

PURPOSE: Chemotherapy-induced peripheral neuropathy (CIPN) is common and leads to suboptimal treatment. Acetyl-L-carnitine (ALC) is a natural compound involved in neuronal protection. Studies have suggested ALC may be effective for the prevention and treatment of CIPN. PATIENTS AND METHODS: A 24-week randomized double-blind trial comparing ALC (3,000 mg per day) with placebo in women undergoing adjuvant taxane-based chemotherapy was conducted. The primary objective was to determine if ALC prevents CIPN as measured by the 11-item neurotoxicity (NTX) component of the Functional Assessment of Cancer Therapy (FACT) -Taxane scale at 12 weeks. Secondary objectives included changes in 24-week end points, functional status (FACT-Trial Outcome Index [TOI]), fatigue (Functional Assessment of Chronic Illness Therapy [FACIT] -Fatigue), and NTX grade. RESULTS: A total of 409 patients were evaluable (208 received ALC; 201, placebo). In a multivariate linear regression, week-12 scores were 0.9 points lower (more CIPN) with ALC than placebo (95% CI, -2.2 to 0.4; P = .17), whereas week-24 scores were 1.8 points lower with ALC (95% CI, -3.2 to -0.4; P = .01). Patients receiving ALC were more likely to have a > 5-point decrease in FACT-NTX scores (38% v 28%; P = .05), and FACT-TOI scores were 3.5 points lower with ALC (P = .03). Grade 3 to 4 neurotoxicity was more frequent in the ALC arm (eight v one). No differences between arms were observed for FACIT-Fatigue or other toxicities. Serum carnitine level increased with ALC but remained stable with placebo. CONCLUSION: There was no evidence that ALC affected CIPN at 12 weeks; however, ALC significantly increased CIPN by 24 weeks. This is the first study to our knowledge showing that a nutritional supplement increased CIPN. Patients should be discouraged from using supplements without proven efficacy.

Effect of acute administration of L-acetyl carnitine on cerebral blood flow in patients with chronic cerebral infarct.

The effect of L-acetyl carnitine (L-AC) on cerebral blood flow (CBF) was evaluated in 20 patients with chronic cerebrovascular disease, who suffered an ischaemic stroke at least 6 months before the study. All patients performed a CT scan and were investigated with xenon-133 by brain dedicated single photon emission computed tomography (SPECT, Tomomatic 32, Medimatic Inc., Copenhagen). A single high dose (1.5 g) of L-acetyl carnitine was intravenously administered to 10 patients, while sodium acetate as placebo was injected to 10 other subjects. Cerebral blood flow (ml/min x 100 g) was evaluated before and 45 min after the injection. No changes were observed after placebo injection (43 +/- 12 ml/min x 100 g versus 43 +/- 10 ml/min x 100 g). CBF increased (from 42 +/- 9 ml/min x 100 g to 46 +/- 9, P less than 0.05) in both ipsilateral and contralateral hemisphere, the ischaemic area, but not in the stroke corresponding zone. It was concluded that L-acetyl carnitine at the i.v. dosage of 1.5 g acutely enhanced CBF in patients with chronic cerebral infarct.