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Meridia (sibutramine): 35 cases of amnesia reported world-wide
Saturday, December 04, 2004 10:08 pm Email this article
Thirty-five cases of amnesia have been reported world-wide associated with the use of the prescription diet pill Meridia (sibutramine) according to a report in the December 4, 2004 issue of the British Medical Journal. Case #1: 39-yr-old woman, amnesia plus migranes started one month after she started the drug
A 39-year-old woman reported memory loss one month after she started taking the drug, and progressively got worse until her daily activities were severely affected.
She also experienced increased migranes
She also experienced an increase in the frequency of migraines associated with a stiff neck.
She improved within 2 weeks after stopping, and resolved completely after 6 weeks
Within two weeks after stopping the drug her amnesia improved, and had resolved completely after six weeks.
Case #2: 50-yr-old woman, amnesia plus headache and insomnia one day after starting
Another case invovled a 50-year-old woman who experienced amnesia, headache, and insomnia one day after she started taking 10 mg of Meridia (sibutramine) per day.
Her symptoms resolved within 4 days of stopping
Her symptoms resolved four days after stopping the drug.
33 more cases in the WHO database
The World Health Organization’s international database contains 33 more reports of amnesia associated with Meridia (sibutramine).
Meridia only drug suspected in 25 of 33 cases
In 25 of the 33 cases, Meridia (sibutramine) was the only drug suspected.
Amnesia started within 4 days in 13 of the cases
In 13 of the cases, the amnesia started within four days of starting on Meridia (sibutramine).
Amnesia resolved in 10 of 13 cases after stopping the drug
Of those thirteen, 10 recovered after stopping the drug.
(Comment: The report does not say if the other 3 did not recover or if there was simply no followup report for them.)
3 of the 33 people also had a stroke
Three patients with Meridia (sibutramine)-induced amnesia also had a stroke, and one of them also had hypertension induced by the drug.
Seven patients experienced confusion, dizziness, impaired speech, or abnormal vision; may be due to insufficient blood flow to the brain
Seven other patients experienced symptoms that might be caused by insufficient blood flow to the brain, including
- impaired speech, and
- abnormal vision.
Meridia-induced amnesia might be due to increased serotonin
The amnesia might be due to Meridia’s (sibutramine) effect on increasing serotonin by blocking serotonin reuptake according to the article.
Other SSRI’s have been associated with memory loss
They note that other serotonin reuptake inhibitors such as Prozac (fluoxetine) have also been associated with memory loss.
Meridia causes very little effect on serotonin at a dose less than 20 mg
Comment: Although Meridia (sibutramine) is marketed as being both a noradrenaline reuptake inhibitor and a serotonin reuptake inhibitor, Meridia (sibutramine) does not inhibit serotonin reuptake except at higher-than-recommended doses (20 mg or more, while the recommended dose is 5-15 mg).
10 mg inhibits less than 10% of serotonin reuptake
A dose of 10 mg of Meridia (sibutramine) daily inhibits less than 10 percent of serotonin reuptake according to Luscombe et al (1990).
20 mg inhibits 20-30% of serotonin reuptake, 30 mg 40% of reuptake
A dose of 20 mg per day inhibits 20-30 percent of serotonin reuptake, and a dose of 30 mg per day, given as 15 mg twice a day, inhibits approximately 40 percent of serotonin reuptake (Luscombe et al, 1990).
Dose only revealed for one patient
Unfortunately, the article about Meridia-induced amnesia only lists the dose for one person (10 mg).
Patients might have taken a higher than recommended dose
Some doctors have told me that they have found that 5 or 10 mg is not really enought to be effective, therefore, it certainly seems possible that some of these people might have been prescribed 20 mg or more, or that they took a higher dose themselves.
Clark D, Harrison-Woolrych M. Sibutramine may be associated with memory impairment. BMJ. 2004 Dec 4, 329(7478):1316.
AUTHOR’S CONTACT INFORMATION
Intensive Medicines Monitoring Programme (IMMP)
New Zealand Pharmacovigilance Centre
Department of Preventive and Social Medicine
University of Otago
Dunedin, New Zealand
PO Box 913
Dunedin, New Zealand
Luscombe GP, Slater NA, Lyons MB, Wynne RD, Scheinbaum ML, Buckett WR. Effect on radio labelled-monoamine uptake in vitro of plasma taken from healthy volunteers administered the antidepressant sibutramine HCl. Psychopharmacology, 1990, 100(3):345-9.
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