Duloxetine: Cymbalta Generic Approved but Caution Exists

Duloxetine cautions serotonin syndrome

Duloxetine, the generic drug for Cymbalta, was just recently approved by the FDA even though caution exists in taking this drug.  The Duloxetine delayed-release capsules are used to treat depression and other disorders. When generics finally become available, they tend to be much easier for the public to obtain through a variety of insurances. Even though the FDA reassures patients that the use of this medication is safe, due to their strict guidelines when they approve medications, there is some concern with a drug reaction called serotonin syndrome.

Duloxetine is a noradrenaline reuptake inhibitor and serotonin drug that is used to treat major depression, generalized anxiety and neuropathy pain in diabetics. The TGA (Therapeutic Goods Administration) in Australia has received about 31 reports of serotonin syndrome symptoms from patients using the generic drug since September 2013. Some of the reports included other medications that seemed to work together in causing the symptomatology, but within at least 21 of the cases Duloxetine was the only culprit causing the symptoms. Duloxetine, the Cymbalta Generic that was approved by the U.S. FDA, will obviously continue to cause certain health professionals outside the U.S. to be aware that caution with the drug exists.

It is highly recommended to take Duloxetine with caution, especially when mixing the medication with Saint John’s Wort, other SSRI’s, tryptophan, opioids and tricyclic depressants. Serotonin syndrome causes problems with varied mental states (agitation, confusion), dysfunction of the autonomic system (tachycardia, excessive sweating) and neuromuscular hyperactivity (tremors, hyper-reflexes). Serotonin syndrome is considered a life-threatening problem if it is not treated appropriately.

The most common dosage of Duloxetine is 60 mg taken daily. Dosages of 30 mg taken daily were reported with serotonin syndrome concerns in five cases, and symptoms from 90 mg to 120 mg were reported in two other cases. Complete data describing the time when the syndrome symptoms started was not available for investigation, although five of the reports stated patients had trouble only a few days after consuming the medication. In one report, a patient with reported depression and back pain needed hospitalization when taking Duloxetine.  After three weeks of taking 30 mg daily, the patient was advised to increase the dosage to 60 mg daily, along with fentanyl patches. When the medication was increased, the patient started to experience severe sweating, ataxia and tremors.

In the TGA review, health care professionals were reminded that while serotonin syndrome usually occurs when serotonergic medications are used together; it can take just a single drug to cause the symptoms as well. Doctors need to stay alert in all cases involving treatments when patients use Duloxetine. If serotonin symptoms occur, health care practitioners need to consider having the patient stop taking Duloxetine. Patients with hepatic impairment should not take the drug. Although, people with end-stage renal disease can use the drug at lower dosages safely it seems.

The FDA mentions that depression and other serious psychiatric illnesses are a common cause of suicide. So close monitoring is advised from mental health professionals when patients use various psychiatric medications. Duloxetine, as well as other prescribed psychotropic medications, are given out with an information pamphlet that indicates risks and usages. Some side effects, while taking Cymbalta and the generic Duloxetine, include dizzy spells, upset stomach, dry mouth, sleepiness, lack of appetite, fatigue and sweating. The FDA assures consumers that the generic Duloxetine drugs have the same strength and quality of brand name products, and that all generics have to pass the same quality regime. So Duloxetine, the FDA approved Cymbalta generic, will soon be prescribed to patients even though some caution continues to exist.

By Tina Elliott



Australian Prescriber