Cymbalta (duloxetine) Drug Information by MedicineNet.com

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Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD

GENERIC NAME: duloxetine

BRAND NAME: Cymbalta

DRUG CLASS AND MECHANISM: Duloxetine is a selective serotonin and norepinephrine reuptake inhibitor (SNRI) used for treating depression, anxiety disorder and pain associated with diabetic peripheral neuropathy or fibromyalgia. Other drugs in this class include milnacipran (Savella), venlafaxine (Effexor), and desvenlafaxine (Pristiq). Duloxetine affects neurotransmitters, the chemicals that nerves within the brain make and release in order to communicate with one another. Neurotransmitters either travel across the space between nerves and attach to receptors on the surface of nearby nerves or they attach to receptors on the surface of the nerves that produced them, to be taken up by the nerve and released again (a process referred to as re-uptake).

Many experts believe that an imbalance among neurotransmitters is the cause of depression as well as other psychiatric disorders. Serotonin and norepinephrine are two neurotransmitters released by nerves in the brain. Duloxetine works by preventing the reuptake of serotonin and epinephrine by nerves after they have been released. Since uptake is an important mechanism for removing released neurotransmitters and terminating their actions on adjacent nerves, the reduced uptake caused by duloxetine increases the effect of serotonin and norepinephrine in the brain. The mechanism responsible for its effectiveness treating pain is not known but also is thought to involve its effects on serotonin and norepinephrine in the brain. Duloxetine was approved by the FDA in August 2004.

PRESCRIPTION: Yes

GENERIC: No

PREPARATIONS: Delayed-release capsules: 20, 30, and 60 mg

STORAGE: Capsules should be stored at room temperature, between 15 to 30 C (59 to 86 F).

PRESCRIBED FOR: Duloxetine is used for the treatment of depression, generalized anxiety disorder, and pain associated with diabetic peripheral neuropathy or fibromyalgia.

DOSING: The recommended dose for treating depression is 20 or 30 mg twice daily or 60 mg once daily. Patients may be started with 30 mg once daily for one week before the dose is advanced to 60 mg daily. The recommended dose for anxiety disorder, pain associated with diabetic neuropathy or fibromyalgia is 60 mg daily. There is no evidence that doses greater than 60 mg/day provide additional benefits.

DRUG INTERACTIONS: Duloxetine should not be used in combination with a monoamine oxidase inhibitor (MAOI) such as phenelzine (Nardil), tranylcypromine (Parnate), isocarboxazid (Marplan), and selegiline (Eldepryl), or within 14 days of discontinuing the MAOI. At least 5 days should be allowed after stopping duloxetine before starting an MAOI. Combinations of SNRIs and MAOIs may lead to serious, sometimes fatal, reactions including very high body temperature, muscle rigidity, rapid fluctuations of heart rate and blood pressure, extreme agitation progressing to delirium, and coma. Similar reactions may occur if duloxetine is combined with antipsychotics, tricyclic antidepressants or other drugs that affect serotonin in the brain (for example, tryptophan, and sumatriptan (Imitrex).

Fluoxetine (Prozac, Serafem), paroxetine (Paxil, Paxil CR, Pexeva), fluvoxamine (Luvox), and quinidine (Quinidine Gluconate, Quinidine Sulfate) increase blood levels of duloxetine by reducing its metabolism in the liver. Such combinations may increase adverse effects of duloxetine.