Screening Patients for Bipolar Disorder — A major depressive episode may be the initial presentation of bipolar disorder. It is generally believed (though not established in controlled trials) that treating such an episode with an antidepressant alone may increase the likelihood of precipitation of a mixed/manic episode in patients at risk for bipolar disorder. Whether any of the symptoms described above represent such a conversion is unknown. However, prior to initiating treatment with an antidepressant, patients with depressive symptoms should be adequately screened to determine if they are at risk for bipolar disorder; such screening should include a detailed psychiatric history, including a family history of suicide, bipolar disorder, and depression. It should be noted that duloxetine is not approved for use in treating bipolar depression.
Pooled MDD and GAD Trials— Table 3 gives the incidence of treatment-emergent adverse reactions in MDD and GAD placebo-controlled trials for approved indications that occurred in 2% or more of patients treated with duloxetine and with an incidence greater than placebo.
Table 3: Treatment-Emergent Adverse Reactions: Incidence of 2% or More in MDD and GAD Placebo-Controlled Trials
| System Organ Class / Adverse Reaction | Percentage of Patients Reporting Reaction |
| Duloxetine (N=2995) | Placebo (N=1955) |
Cardiac Disorders
Palpitations
| 2 | 2 |
Eye Disorders
Vision blurred
| 3 | 2 |
Gastrointestinal Disorders
Nausea
Dry mouth
Diarrhea
Constipation
b
Abdominal pain
c
Vomiting
|
25
15
10
10
4
5
|
9
6
7
4
4
2
|
General Disorders and Administration Site Conditions
Fatigue
d | 10 | 6 |
Investigations
Weight decreased
b | 2 | <1 |
Metabolism and Nutrition Disorders
Decreased appetite
e | 7 | 2 |
| Nervous System Disorders | | |
Dizziness
Somnolence
f
Tremor
| 10
10
3
| 6
4
<1
|
| Psychiatric Disorders | | |
Insomnia
g
Agitation
h
Anxiety
Libido decreased
i
Orgasm abnormal
j
Abnormal dreams
k | 10
5
3
4
3
2
| 6
3
2
1
<1
1
|
Reproductive System and Breast Disorders
Erectile dysfunction
l
Ejaculation delayed
b,j
Ejaculation disorder
l,m |
4
3
2
|
1
<1
<1
|
Respiratory, Thoracic, and Mediastinal Disorders
Yawning
| 2 | <1 |
Skin and Subcutaneous Tissue Disorders
Hyperhidrosis
| 6 | 2 |
Vascular Disorders
Hot Flush
| 2 | <1 |
a The inclusion of an event in the table is determined based on the percentages before rounding; however, the percentages displayed in the table are rounded to the nearest integer.
b Events for which there was a significant dose-dependent relationship in fixed-dose studies, excluding three MDD studies which did not have a placebo lead-in period or dose titration.
c Also includes abdominal pain upper, abdominal pain lower, abdominal tenderness, abdominal discomfort, and gastrointestinal pain
d Also includes asthenia
e Also includes anorexia
fAlso includes hypersomnia and sedation
g Also includes middle insomnia, early morning awakening, and initial insomnia
h Also includes feeling jittery, nervousness, restlessness, tension, and psychomotor agitation
i Also includes loss of libido
j Also includes anorgasmia
k Also includes nightmare
l Male patients only
m Also includes ejaculation failure and ejaculation dysfunction
DPNP, OA, and CLBP — Table 4 gives the incidence of treatment-emergent adverse events that occurred in 2% or more of patients treated with duloxetine (determined prior to rounding) in the premarketing acute phase of DPNP, OA, and CLBP placebo-controlled trials and with an incidence greater than placebo.
Table 4: Treatment-Emergent Adverse Reactions Incidence of 2% or More in DPNP, OA, and CLBP Placebo-Controlled Trials
a
| System Organ Class / Adverse Reaction | Percentage of Patients Reporting Reaction |
| Duloxetine(N=2621) | Placebo(N=1672) |
| Gastrointestinal Disorders | | |
| Nausea | 23 | 7 |
| Dry Mouth
b | 11 | 3 |
| Constipation
b | 10 | 3 |
| Diarrhea | 9 | 6 |
| Abdominal Pain
c | 6 | 5 |
| Vomiting | 3 | 2 |
| Dyspepsia
d | 2 | 1 |
General Disorders and Administration Site Conditions
Fatigue
e | 11 | 5 |
| Infections and Infestations | | |
| Nasopharyngitis | 5 | 4 |
| Upper Respiratory Tract Infection | 4 | 4 |
| Influenza | 3 | 2 |
Metabolism and Nutrition Disorders
Decreased Appetite
b,f | 9 | 1 |
| Musculoskeletal and Connective Tissue Disorders | | |
| Musculoskeletal Pain
b,g | 4 | 4 |
| Muscle Spasms | 3 | 2 |
| Nervous System Disorders | | |
| Headache | 13 | 9 |
| Somnolence
b,h | 12 | 3 |
| Dizziness | 10 | 5 |
| Paraesthesia
i | 2 | 2 |
| Tremor
b | 2 | <1 |
Psychiatric Disorders
Insomnia
b,j
Agitation
k | 10
3
| 6
<1
|
Reproductive System and Breast Disorders
Erectile dysfunction
b,j
Ejaculation Disorder
m | 4
2
| <1
<1
|
| Respiratory, Thoracic and Mediastinal Disorders | | |
| Cough | 3 | 2 |
| Oropharyngeal Pain
b | 2 | 2 |
| Skin and Subcutaneous | | |
| Tissue Disorders | | |
| Hyperhidrosis | 6 | 1 |
| Vascular Disorders | | |
| Flushing
n | 3 | 1 |
a The inclusion of an event in the table is determined based on the percentages before rounding; however, the percentages displayed in the table are rounded to the nearest integer.
b Incidence of 120 mg/day is significantly greater than the incidence for 60 mg/day.
c Also includes abdominal discomfort, abdominal pain lower, abdominal pain upper, abdominal tenderness and gastrointestinal pain
d Also includes stomach discomfort
e Also includes asthenia
f Also includes anorexia
g Also includes myalgia and neck pain
h Also includes hypersomnia and sedation
i Also includes hypoaesthesia, hypoaesthesia facial and paraethesia oral
j Also includes middle insomnia, early morning awakening, and initial insomnia
k Also includes feeling jittery, nervousness, restlessness, tension and psychomotor hyperactivity
l Male patients only (N=885 for duloxetine , 494 for placebo)
m Male patients only (N=885 for duloxetine , 494 for placebo). Also includes ejaculation failure
n Also includes hot flush
Absorption and Distribution — Orally administered duloxetine is well absorbed. There is a median 2-hour lag until absorption begins (T
lag), with maximal plasma concentrations (C
max) of duloxetine occurring 6 hours post dose. Food does not affect the C
max of duloxetine, but delays the time to reach peak concentration from 6 to 10 hours and it marginally decreases the extent of absorption (AUC) by about 10%. There is a 3-hour delay in absorption and a one-third increase in apparent clearance of duloxetine after an evening dose as compared to a morning dose.
The apparent volume of distribution averages about 1640 L. Duloxetine is highly bound (>90%) to proteins in human plasma, binding primarily to albumin and α
1-acid glycoprotein. The interaction between duloxetine and other highly protein bound drugs has not been fully evaluated. Plasma protein binding of duloxetine is not affected by renal or hepatic impairment.
Metabolism and Elimination — Biotransformation and disposition of duloxetine in humans have been determined following oral administration of
14C-labeled duloxetine. Duloxetine comprises about 3% of the total radiolabeled material in the plasma, indicating that it undergoes extensive metabolism to numerous metabolites. The major biotransformation pathways for duloxetine involve oxidation of the naphthyl ring followed by conjugation and further oxidation. Both CYP1A2 and CYP2D6 catalyze the oxidation of the naphthyl ring
in vitro. Metabolites found in plasma include 4-hydroxy duloxetine glucuronide and 5-hydroxy, 6-methoxy duloxetine sulfate. Many additional metabolites have been identified in urine, some representing only minor pathways of elimination. Only trace (<1% of the dose) amounts of unchanged duloxetine are present in the urine. Most (about 70%) of the duloxetine dose appears in the urine as metabolites of duloxetine ; about 20% is excreted in the feces. Duloxetine undergoes extensive metabolism, but the major circulating metabolites have not been shown to contribute significantly to the pharmacologic activity of duloxetine.
Carcinogenesis — Duloxetine was administered in the diet to mice and rats for 2 years.
In female mice receiving duloxetine at 140 mg/kg/day (11 times the maximum recommended human dose [MRHD, 60 mg/day] and 6 times the human dose of 120 mg/day on a mg/m
2 basis), there was an increased incidence of hepatocellular adenomas and carcinomas. The no-effect dose was 50 mg/kg/day (4 times the MRHD and 2 times the human dose of 120 mg/day on a mg/m
2 basis). Tumor incidence was not increased in male mice receiving duloxetine at doses up to 100 mg/kg/day (8 times the MRHD and 4 times the human dose of 120 mg/day on a mg/m
2 basis).
In rats, dietary doses of duloxetine up to 27 mg/kg/day in females (4 times the MRHD and 2 times the human dose of 120 mg/day on a mg/m
2 basis) and up to 36 mg/kg/day in males (6 times the MRHD and 3 times the human dose of 120 mg/day on a mg/m
2 basis) did not increase the incidence of tumors.
Mutagenesis — Duloxetine was not mutagenic in the
in vitro bacterial reverse mutation assay (Ames test) and was not clastogenic in an
in vivo chromosomal aberration test in mouse bone marrow cells. Additionally, duloxetine was not genotoxic in an
in vitro mammalian forward gene mutation assay in mouse lymphoma cells or in an
in vitro unscheduled DNA synthesis (UDS) assay in primary rat hepatocytes, and did not induce sister chromatid exchange in Chinese hamster bone marrow
in vivo.
Impairment of Fertility
— Duloxetine administered orally to either male or female rats prior to and throughout mating at doses up to 45 mg/kg/day (7 times the maximum recommended human dose of 60 mg/day and 4 times the human dose of 120 mg/day on a mg/m
2 basis) did not alter mating or fertility.