A class of antidepressants called selective serotonin reuptake inhibitors (SSRIs) are often prescribed to help menopausal women deal with their symptoms. Now research is suggesting this could put them at an increased risk for bone fracture.
Researchers at Northeastern University in Boston analyzed data from the PharMetrics Claims Database then published their findings in the journal The BMJ, Injury Prevention. The database gathers information on about sixty-one million patients undergoing drug treatments in the U.S. For this study, they focused on 137,031 women who were treated with SSRIs between 1998 and 2010, and who were aged 40 to 64, about the age of menopause. The women chosen were not being treated for depression, but received SSRI prescriptions for other reasons. They then compared information from that group with 236,294 similar women who received an indigestion medication instead, as a control group.
The researchers ignored the first six months of treatment, allowing time for the bone density to be affected. Then, after comparing the two groups, the researchers realized the results were significant. The group who received SSRIs faced a 76% higher risk of bone fracture after the first year studied, compared to the control group. After two years, there was a 73% difference, and after five years, a 67% difference. This showed that the risk of bone fracture continued for at least a five year duration without reducing significantly.
Based on the study results, the researchers suggest that when taking SSRI medications, a shorter duration of treatment may decrease the risk of bone fracture in the menopausal patients.
The SSRI drugs the researchers looked at in the study included citalopram, hyrdrobromide, escitalopram oxalate, fluoxetine hyrdrochloride, fluvoxamine maleate, paroxetine hydrochloride, and sertraline hydrochloride. SSRIs are usually prescribed to treat depression and are the third most frequently prescribed drug in the U.S. Doctors will often use the drugs as an alternative to hormone replacement therapy (HRT) as women experience menopause. The SSRI medication can reduce the severity of night sweats, hot flashes, and other bothersome menopause symptoms. Paroxetine is often prescribed for this purpose at about a third of the dosage used to treat psychiatric disorders like depression, and has recently earned official approval in the U.S. to treat vasomotor menopausal symptoms (VMS). In addition to symptoms of menopause, SSRIs are often prescribed by doctors to treat irritable bowel syndrome, premature ejaculation, and other medical conditions.
The researchers believe the SSRI drugs increase the risk of bone fracture by interfering with the turnover of bone within the body. Bones are constantly broken down and reformed in the body. However, hormonal changes during menopause as well as other factors can alter this cycle of bone breakdown and formation, leading to increased bone breakdown without an equivalent increase in bone formation. When antidepressant drugs interfere, researchers believe, they shift the balance toward bone thinning. This leads to lower bone mineral density, and these weaker bones are then at a higher risk of breaking.
There are some limitations to the study, however. The researchers did not look at varying dosages within the SSRI group. As well, some doctors point out that the risk of bone fracture in the age group studied is naturally low, so the results may seem more significant than they actually are.
When women experience menopause, there are some medications that can reduce their risk of bone fracture, potentially mitigating the effects of the SSRIs. These include intravenous infusions like Prolia that are given in medical clinics. Medications like this reduce the action of osteoclasts which break down bone, helping to strengthen bone so it can better resist fracture.
The research suggests that women who are potentially taking SSRI medication for menopausal symptoms should weigh their risks and benefits. However, more research may be needed to determine if lower doses of SSRIs can decrease the fracture risk.