PKHS asked
I have taken 60mg of duloxetine for over 10 years. Is it possible to develop new side effects after such a long exposure to the drug? I have infrequent uncontrollable tremors in my leg. My Neurologist says there is not any indication of problems in my brain, however these tremors have recently changed to include my entire right side. I am a 63 yr old woman who was diagnosed with CHF 2 years ago and placed on blood pressure meds. Any suggestions?
Answer
Tremors are an associated side effect of Cymbalta (duloxetine) use, but it is relatively uncommon. Additionally, there is little data in regard to when in therapy you are most susceptible to this side effect unfortauntely. If you are having muscle spams or tremor manifest after 10 years of use, Cymbalta may be a potential culprit to consider.
Muscle Spasm And Tremor On Cymbalta
Adult clinical trials of Cymbalta reported about a 2 to 3% incidence rate of tremors in those taking the medication. Per the manufacturer of Cymbalta, Eli Lilly, the side effect is dose dependent with higher doses causing significantly more than of tremor than lower doses.
If muscle tremors to begin to occur while you are taking Cymbalta, it is important to rule out a rare, but dangerous side effect, serotonin syndrome. Serotonin syndrome can occur when too much of the neurotransmitter serotonin builds up in the brain, mainly due to high doses of multiple serotonergic drugs. Symptoms include:
- Mental status changes (e.g., agitation, hallucinations)
- Fast heart rate
- Dizziness
- Sweating
- Tremor
- Rigidity
If you experience tremors on Cymbalta, it is important to speak with your doctor and be evaluated for your symptoms. If serotonin syndrome has been ruled out, the tremors you are experiencing may simply be a side effect of the medication which, in most cases, resolves upon discontinuation or a change in medication.
