TCAs Tricyclic Antidepressants
Tricyclic antidepressants (TCAs) are often prescribed in severe cases of depression or when SSRI medications do not work. Tricyclic antidepressants include amitriptyline (Elavil), amoxapine (Asendin), desipramine (Norpramin), doxepin (Adapin, Sinequan, Zonalon), imipramine (Tofranil), nortriptyline (Aventyl, Pamelor), protriptyline (Vivactil), and trimipramine (Surmontil).
How do TCAs work? TCAs block the uptake of serotonin and norepinephrine, thereby providing higher levels of these neurotransmitters at the brain receptor site. Besides increasing norepinephrine and serotonin, amoxapine also increases the neurotransmitter dopamine.
Who should not use these medications?
* Individuals who have allergic reactions to TCAs
* Individuals in the acute recovery phase following a heart attack
* Individuals with glaucoma
* Individuals with urine retention
* Individuals who are currently taking or have taken MAOIs within the past 2 weeks (Phenelzine , and tranylcypromine , are examples of MAOIs.) (Do not start taking MAOIs for at least 2 weeks after stopping TCAs. This is a general warning; see drug and food interactions for low-dose use together.)
* Individuals taking some medications that alter heart rhythm such as thioridazine (Mellaril) or cisapride (Propulsid)
* Tricyclic antidepressants are taken orally by tablet, capsule, or oral solution.
* Elderly individuals and adolescents often require lower doses.
Elderly: Elderly individuals require lower doses. Elderly individuals are more susceptible to sedative effects and may feel faint when standing up, therefore increasing the risk of falls and injuries.
Children: The following TCAs are approved in the United States for treating adolescents with depression who are older than 12 years:
* Amoxapine (approved for persons older than 16 years)
Drug or food interactions: Tell the doctor what medications are currently being taken because many medicines interact with TCAs. Do not take any nonprescription or herbal medications without first consulting the doctor or pharmacist. The following are examples of interactions, but they do not represent a complete list.
* TCAs may increase the blood levels and/or risk of toxicity of the following medications:
o MAOIs (These may cause serious and sometimes fatal reactions; some TCAs have been used safely with MAOIs, but the dose of TCAs must be increased very slowly and the person must strictly adhere to MAOI dietary restrictions.)
o Sympathomimetics such as pseudoephedrine (Sudafed)
* The following substances may increase the toxicity of TCAs:
o Alcohol or other drugs that depress the central nervous system such as medications taken for insomnia
o Medications, such as antihistamines (Benadryl), that may produce similar side effects
o Antifungal medications such as ketoconazole (Nizoral) or fluconazole (Diflucan)
o SSRIs, venlafaxine, and nefazodone (may increase risk for serotonin syndrome—symptoms include hypertension, fever, muscle tremor, or confusion)
o Tramadol (Ultram) (may increase risk of seizures)
o Medications such as cisapride, thioridazine, quinidine, antihistamines, erythromycin, dofetilide, and pimozide that also increase the risk for abnormal heart rhythm
o Valproic acid
* Other interactions include the following:
TCAs may decrease the ability for clonidine to lower blood pressure levels.
Carbamazepine may decrease TCA effectiveness.
St. John’s wort may decrease TCA effectiveness and increase the risk of serotonin syndrome.
Side Effects: This is NOT a complete list of possible side effects reported with TCAs. A doctor, health care provider, or pharmacist can discuss a more complete list of side effects.
* Confusion, agitation, or hallucinations (Contact a doctor immediately if these occur.)
* Severe diarrhea, fever, sweating, muscle stiffness, or tremors (These may be symptoms of neuroleptic malignant syndrome. Contact a doctor immediately.)
* Rapid or abnormal heartbeat or fainting (Contact a doctor immediately if these occur.)
* Changes in sexual interest or ability
* Manic episodes in persons with bipolar disorder (If not combined with a mood-stabilizing medication, SSRIs may induce manic episodes in individuals with bipolar disorder .)
* Drowsiness (Caution is advised when operating machinery, driving, or performing other tasks that require alertness.)
* Photosensitivity (increased risk of sunburn) (Use protective clothing, such as long sleeves and hats, and sunscreen to decrease the risk of sunburn.)
* Dry mouth
* Urine retention
* Blurred vision
* Lightheadedness when standing up from a sitting or lying position (Stand up gradually from lying down or sitting positions.)
* Seizures (TCAs lower the threshold for seizures, that is, seizures may occur more easily in the person taking TCAs. Caution is advised for individuals prone to seizures or those who have a history of seizures.)