Buspirone

Buspirone is another of those medications that was introduced in the 80's, and was marketed for the treatment of anxiety. Most of the published studies on buspirone were done around 1990.

While many antidepressants simply increase the amount of serotonin or other neurotransmitters by blocking neurotransmitter re-uptake into neurons, buspirone works by directly stimulating one of the target receptors for serotonin, called the 5HT-1A receptor.

As with many new drugs, there was a wave of enthusiasm, which eventually faded. At this point buspirone is rarely prescribed.

In my opinion, it could be a useful and well-tolerated adjunct, to try in the following situations:

1) to treat generalized anxiety disorder
2) to augment antidepressants (i.e. to add to an antidepressant which isn't working well enough)
3) to treat antidepressant-induced jaw or tooth grinding (bruxism)
4) to treat aggressive or self-injurious behaviour; it may be particularly helpful in elderly patients with dementia, or in mentally handicapped patients
5) to treat migraine (a common comorbid problem among depressed or anxious patients)
6) to help with opiate withdrawal
7) to help quit smoking

Side effects are usually mild and subside with time; they include dizziness, nausea, sweating, or nervousness. About 10% of people in the clinical trials of buspirone discontinued the medication due to side effects.

Buspirone is metabolized through the cytochrome P450 3A4 system in the liver; because of this its levels in the body can be substantially increased by other medications or grapefruit juice, so these types of interactions have to be considered when choosing a dose.

I've been curious to revisit the evidence base for buspirone; here is my review of the literature:

1) Using buspirone as an augmentation to antidepressants, for treatment of depression:

http://www.ncbi.nlm.nih.gov/pubmed/17628435
{a good, important study from NEJM in 2006: 565 depressed patients who had not remitted despite receiving high-dose citalopram, were given augmentation therapy with either bupropion SR or buspirone. That is, the bupropion or buspirone was added onto their daily regimen of citalopram, and the patients were followed over at least 7 weeks. Both groups did similarly well, with about 30% of both groups having a remission. The bupropion group did slightly better in a few ways. Unfortunately there was no placebo augmentation group}

2) Treating generalized anxiety:

http://www.ncbi.nlm.nih.gov/pubmed/8666569
{a small study from 1996 showing that buspirone helps reduce anxiety symptoms in patients who also have mild depression; but the reduction in anxiety symptoms (about 50%) is only modestly different from placebo (about 35%) }

http://www.ncbi.nlm.nih.gov/pubmed/3320034
{this study from 1987 had a one-year follow-up of 700 patients. But it was open-label (no randomization, no placebo group). It did show that the patients taking buspirone for treatment of generalized anxiety showed sustained improvement, and tolerated the medication well}

http://www.ncbi.nlm.nih.gov/pubmed/17984162
{this 2007 study compares the effect sizes of numerous different medication treatments for generalized anxiety; buspirone fares particularly poorly, with a "non-significant" effect size of 0.17; SSRI's and venlafaxine do slightly better, and the novel anticonvulsant pregabalin actually does best. Complementary and alternative medications had a negative effect on symptoms, in this analysis. However, this meta-analysis is limited by the fact that most of the buspirone studies were done over 10 years ago and most of the results are from short-term treatment.}

http://www.ncbi.nlm.nih.gov/pubmed/2211567
{one of the small randomized studies comparing buspirone with a benzodiazepine for treatment of anxiety; the study shows similar effectiveness. Given that buspirone is non-addictive, it makes buspirone a more attractive option}


3) Treating other anxiety conditions:

http://www.ncbi.nlm.nih.gov/pubmed/2407755
{one of the studies showing that buspirone is NOT effective for treating panic disorder}

4) Improving cognitive function in schizophrenia:

http://www.ncbi.nlm.nih.gov/pubmed/17628435
{this 2007 study had a good randomized design, and 6 months of follow-up; it claimed in the abstract that buspirone had a beneficial effect on cognition when added to antipsychotics in schizophrenia -- but if you take a look at the actual data in the article, the differences in buspirone vs. placebo groups are very small. So I'm not impressed.}

5) Treating migraine:

http://www.ncbi.nlm.nih.gov/pubmed/16109114
{a small 2005 study in a headache journal looking at a group of 74 patients with migraine over 6 weeks of treatment; it showed that low-dose buspirone (10 mg) reduces migraine frequency by about 40%, and reduced anxiety scores by about 20%, both of which a substantial difference compared to placebo. The improvement in anxiety did not depend on the improvement in headache, they appeared to be separate, independent effects.}

6) Treating acute heroin withdrawal:

http://www.ncbi.nlm.nih.gov/pubmed/15876901
{an interesting 2005 study showing that 45 mg per day of buspirone can reduce symptoms of heroin withdrawal over a 2-week period; looking at the results directly, it appears that the effect is very substantial, that the buspirone almost eliminated withdrawal symptoms}

7) Helping quit smoking:

http://www.ncbi.nlm.nih.gov/pubmed/1739365
{a small 1992 study from Archives of Internal Medicine showing that buspirone helps with nicotine withdrawal, and may help people quit smoking}

8) Treating ataxia:

http://www.ncbi.nlm.nih.gov/pubmed/8806320
{another interesting study from Lancet in 1996, showing that buspirone helps improve symptoms of cerebellar ataxia, a type of brain disease which causes impaired balance & coordination}

9) Treating aggressive behaviours:

http://www.ncbi.nlm.nih.gov/pubmed/2016248
{a small study suggesting that buspirone can help reduce aggression and anxiety in mentally handicapped adults, without causing sedation or cognitive side-effects}

10) Treating bruxism:

http://www.ncbi.nlm.nih.gov/pubmed/10665633
{a 1999 study of 4 cases of SSRI-induced bruxism improving with buspirone}

11) Treating tardive dyskinesia:

http://www.ncbi.nlm.nih.gov/pubmed/8102622
{a 1993 study showing some improvement in tardive dyskinesia (a movement disorder) after treatment with buspirone for 12 weeks. However there are a few other case reports in the literature of buspirone causing worsened symptoms of various movement disorders, such as dystonias or myoclonus (twitching); but the incidence of such side effects appears to be very low}


12) Animal studies:

http://www.ncbi.nlm.nih.gov/pubmed/17312776
{in this study a badger in a zoo (!) was suffering agitation and engaging in self mutilation; "environmental enrichment" initially helped, but the behavioural problems still recurred. Buspirone ended up helping substantially, over an 18 month period, with no side-effects}

http://www.ncbi.nlm.nih.gov/pubmed/15766212
{in another animal study, buspirone helped reduce self-injurious behaviour in a group of rhesus macaques, and it seemed to help more than fluoxetine, with fewer side-effects}