BP TODAY - Tricyclic antidepressants may induce mood conversions in bipolar disorder, according to a new retropective study done in Poland.

The aim of this retrospective study was an analysis of antidepressant-induced mood conversions to mania/hypomania occurring in bipolar inpatients treated with antidepressants in the Affective Disorder Unit of the Institute of Psychiatry and Neurology, Warsaw, in the years 1972-1996.

Methods: The data for analysis were obtained retrospectively from clinical records. In a subgroup of patients prone to mood conversions, a comparison was done of depressive episodes treated with antidepressants with and without a switch to mania/hypomania as well as the frequency of mood conversions induced by particular antidepressant drugs, especially tricyclic (TCA) versus non-TCA drugs.

What are tricyclic antidepressants? Tricyclic antidepressants (TCAs) inhibit the reabsorption (reuptake) of serotonin and norepinephrine by brain cells. To a lesser extent, TCAs also inhibit reabsorption of dopamine. These antidepressants also block other cell receptors, which accounts for many of their side effects. TCAs are called tricyclic because of their chemical structure. They were among the earliest antidepressants developed and remained the first line of treatment for depression before newer antidepressants arrived.

Here are the TCAs approved by the Food and Drug Administration specifically to treat depression, with their generic, or chemical, names followed by available brand names in parentheses:

• Amitriptyline
• Amoxapine
• Desipramine (Norpramin)
• Doxepin (Sinequan)
• Imipramine (Tofranil, Tofranil-PM)
• Nortriptyline (Pamelor)
• Protriptyline (Vivactil)
• Trimipramine (Surmontil)

Some of these medications come in forms that must be injected or as oral solutions that must be mixed with liquids, such as water or juice.

Some of these medications may also be used to treat conditions other than depression.

Because TCAs are less selective about which cells they affect, they typically have more side effects than other antidepressants do.

Side effects of TCAs include:

• Drowsiness
• Dry mouth
• Blurred vision
• Constipation
• Urinary retention
• Dizziness
• Impaired sexual functioning
• Increased heart rate
• Disorientation or confusion
• Headache
• Low blood pressure
• Sensitivity to sunlight
• Increased appetite
• Weight gain
• Nausea
• Weakness

Results:

• Among 333 bipolar patients hospitalized in this period, mood conversions were observed in 118 subjects (35%)

• Mood conversions were significantly more frequently in female (44%) than in male patients (25%), and in patients with depressive episode at the onset of illness (80 vs. 40%).

• Among mood converters, it was found that the depressive episodes with a switch to mania were less severe, shorter, and with shorter duration of antidepressant treatment.

• The risk of switching was higher during treatment with TCA than with non-TCA drugs (36 vs. 17%), the highest with amitriptyline (42% of treated episodes), imipramine (40%) and clomipramine (35%).

Conclusions: The results suggest that bipolar patients prone to mood conversion constitute one third of the inpatient population with this illness. The switch from depression to mania occurred significantly more frequently during treatment with TCA than with non-TCA drugs.

It is hypothesized that anticholinergic activity may contribute to the higher frequency of TCA-induced mood conversions.

What is anticholinergic activity? Anticholinergic means blocking the effects of the neurotransmitter acetylcholine.

Acetylcholine is a neurotransmitter found in both the central nervous system and the peripheral nervous system. Acetylcholine plays an important role both in learning and memory and in sending messages from motor nerves to muscles, especially in the heart, bladder and stomach. It also affects glands. There is a marked deficiency of acetylcholine in the brains of patients with Alzheimer’s Disease. Drugs with anticholinergic effects target acetylcholine receptors.

Drugs that have anticholinergic effects include but are not limited to:

• Tricyclic antidepressants
• Antipsychotics
• SSRI antidepressants Prozac, Zoloft and Paxil
• Diphenhydramine (Benadryl, other generic antihistamines)

[Neuropsychobiology. 2009 Feb 17;59(1):12-16.]

Related posts

• Thyroid hormone gives hope to treatment-resistant bipolar, depression (0)
• New approach may be needed for depression in bipolar patients (0)
• Seroquel XR for bipolar launches (0)
• Schizophrendia drug may be useful for bipolar (0)
• New triple reuptake inhibiting drug invented (0)
• New class of better antidepressants emerging (0)
• Glossary (0)
• Bipolar ups risk of early death (0)
• 8 risk factors for suicide attempts of bipolar patients identified (0)

Leave a Reply