What to know about duloxetine (Cymbalta)
Cymbalta belongs to a class of drugs known as serotonin-norepinephrine reuptake inhibitors (SNRIs).
In this article, we look at the uses and side effects of duloxetine.
Cymbalta can treat depression, diabetic neuropathy, fibromyalgia, and other health issues.
The Food and Drug Administration (FDA) have approved Cymbalta for treating a range of conditions, including:
- diabetic neuropathy
- generalized anxiety disorder
- chronic musculoskeletal pain
Serotonin is a naturally-occurring neurotransmitter that plays a key role in several bodily functions, including:
- mood regulation
- gastrointestinal function
- pain perception
Norepinephrine, or noradrenaline, is both a hormone and a neurotransmitter. It acts mainly in an area of the brainstem known as the locus coeruleus.
This vital hormone plays a role in the "fight-or-flight" response, which is how the body responds to stress.
While this is a natural reaction to specific events and potential danger, the "fight-or-flight" mechanism can often overreact or trigger without a direct cause in people with anxiety or depressive disorders.
Norepinephrine also affects how people perceive:
- blood pressure
- thought processes
Cymbalta for depression and pain
Cymbalta stops the CNS reabsorbing serotonin. It is likely that it has the same effect on norepinephrine.
One possible trigger for depression can be increased levels of proinflammatory cytokines in the CNS. Cytokines are immune cells that affect other cells, such as by increasing and reducing levels of inflammation.
Cymbalta is thought to reduce levels of proinflammatory cytokines and increase anti-inflammatory cytokine activity. However, no scientific studies have conclusively proven this theory.
Cymbalta can also help a person control pain symptoms in the following conditions:
- bone pain
- diabetic neuropathy
Scientists believe that this action is due to duloxetine hydrochloride, the medication's active ingredient, blocking the movement of sodium into cells.
How to take Cymbalta
The right dosage of Cymbalta depends on a person's age and medical condition.
Cymbalta is available as a capsule or a delayed release capsule. A doctor will decide the dosage for an individual, which will depend on their medical condition and age.
People who have an anxiety disorder might start with the drug by taking 60 milligrams (mg) once a day. For some, the doctor may prescribe 30 mg once a day for 7 days, then build the dose to 60 mg once a day.
Initial dosages for people with other conditions include:
- Major depressive disorder: From 40–60 mg per day, with some people starting at 30 mg per day.
- Peripheral neuropathy in diabetes: 60 mg once daily.
- Fibromyalgia: 60 mg once daily, with one week of a daily 30 mg dose.
People can take Cymbalta with or without food but should avoid crushing it or sprinkling it on food.
Common side effects include:
- increased appetite
- excessive sweating, or hyperhidrosis
- severe skin reactions
- irregular glucose control in those with diabetes
- low sodium in the blood
- difficulty urinating
The medication may also cause sexual side effects in both males and females.
The FDA note that Cymbalta may have links to colitis and cutaneous vasculitis.
They also highlight that orthostatic hypotension can occur, which is low blood pressure upon standing up. This can lead to falls and a loss of consciousness, especially in the first week of usage but possibly at any time during a course of treatment.
The manufacturers, Eli Lilly, warn that the drug can lead to liver damage, abnormal bleeding, and skin reactions.
Cymbalta can also lead to serotonin syndrome. This syndrome can be a potentially fatal condition that can cause agitation, hallucinations, and coma, among other symptoms.
Women should not take Cymbalta during pregnancy or when breastfeeding. Animal reproduction studies indicate that Cymbalta is likely to have adverse effects on the development of a fetus in the womb and after birth.
A person can speak to their doctor about how Cymbalta may interact with other drugs they are taking.
Cymbalta may interact with some other drugs.
People should not take the drug while on a course of monoanimase inhibitors (MAOIs).
- tranylcypromine (Parnate)
- selegiline (Eldepryl, Emsam, Zelapar)
- furazolidone (Furoxone)
- rasagiline (Azilect)
- phenelzine (Nardil)
- isocarboxazid (Marplan)
- intravenous methylene blue
- linezolid, an antibiotic
The FDA black box warning advises that people may initially have suicidal thoughts when starting to use Cymbalta, especially children and adolescents. For this reason, doctors monitor people carefully during the first 4 months of treatment for mood changes and other adverse effects.
If any of the following symptoms occur or get worse, people must tell their doctor immediately:
- worsening symptoms of depression
- persistent thoughts of self-harm or suicide
People must avoid alcohol and smoking when taking Cymbalta. Smoking may reduce the drug's effectiveness by a third.
They should also take care when engaging in activities that require a clear and alert mind, such as operating heavy machinery or driving.
Before using Cymbalta, an individual must tell the doctor if they have any of the following diseases or conditions:
- liver disease
- kidney disease
- epilepsy or any other seizures
- a history of suicidal ideation
- a bleeding or clotting disorder
- a history of drug abuse
Screening for bipolar disorder should take place before a doctor prescribes Cymbalta, as it may trigger an episode of mania.
A person should also tell the doctor if they are using the following medications:
- diuretics, or water pills
- nonsteroidal anti-inflammatory drugs (NSAIDs)
- arthritis medication
- treatment for heart rhythm
- treatment for migraines
- St. John's Wort
- other antidepressants
People should not stop taking Cymbalta suddenly. They should speak to the doctor first, as they will need to decrease the dosage gradually.
Some people have brought lawsuits after finishing a course of Cymbalta, claiming that Cymbalta is very hard to stop using. They cite withdrawal symptoms such as tunnel vision and "brain zaps," claiming that the manufacturers played down these adverse effects.
However, courts have ruled that the manufacturers gave adequate warning about the medication's potential withdrawal symptoms.
People should work with their doctor to find the best medication for them.
What are the closest alternatives to Cymbalta?
Finding an alternative to Cymbalta would depend on the indication a person is treating. It is in a class of medications known as SNRIs.
Other popular medications in this class include desvenlafaxine (Pristiq) and venlafaxine (Effexor).Dena Westphalen, PharmD Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.