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Serotonin Reuptake Inhibitors

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Fluoxetine

Brand Name (Manufacturer)

Prozac (Dista)


Type of Drug

Psychoactive-antidepressant


Used For

Fluoxetine is widely used to treat the symptoms of mental depression. It is less frequently used to treat obsessive-compulsive disorder, classic panic disorder, the eating disorder bulimia, and as an appetite suppressant.


General Information

Fluoxetine is an antidepressant that belongs to a class known as serotonin reuptake inhibitors. It is chemically unrelated to tricyclic, tetracyclic, or other known classes of antidepressants. It has become widely used because it is effective and tends to have fewer side effects than older antidepressants (such as the monoamine oxidase inhibitors, for example). It does not cause sedation, weight gain, dry mouth, or constipation.

Antidepressant medications are usually taken over long periods. It takes four weeks or more before steady levels are built up in the blood, and it may take as long for the drug to have an effect on depression. Fluoxetine accumulates in the body's tissues with prolonged use, and the drug may stay in the body for weeks or months after discontinuing therapy. It is especially important that at least five weeks pass after stopping the drug before starting another drug that may interact with fluoxetine.

Fluoxetine has been studied in a number of small clinical trials in people with HIV infection. It general, it has been highly effective in reducing the symptoms of depression. People with low CD4+ counts (under 200) did as well on the drug as people with higher counts.

Fluoxetine is available as capsules for oral administration.


Treatment

For depression, the recommended dose is 20 to 80 mg per day. As with all antidepressants, it is recommended that the lower dose be initially used and increased after several weeks as necessary if the person is not experiencing serious side effects. It may take up to four weeks to notice an effect. The dose may need to be reduced for people with poor liver or kidney function.

For obsessive-compulsive disorder, the recommended treatment is 20 mg per day taken in the morning. Full therapeutic effect may take five weeks or longer. A dose increase may be considered after several weeks if no improvement is seen, but the dose should not exceed 80 mg per day.


Cautions and Warnings

Fluoxetine should not be used by anyone with a known allergy to it. It should not be used by people taking monoamine oxidase (MAO) inhibitor antidepressants. Because fluoxetine and MAO inhibitors remain in the body for a time after stopping therapy, fluoxetine should not be started within fourteen days of receiving a MAO inhibitor. MAO inhibitors should not be started within at least five weeks, and perhaps longer, after stopping fluoxetine.

People with diabetes should use fluoxetine with caution. The drug may alter control of sugar metabolism in the body.

Side Effects

Fluoxetine is relatively well-tolerated. Its most common side effects (which were observed in more than 5% of people taking the drug in clinical trials) include anxiety, nervousness, insomnia, fatigue, tremors, sweating, changes in appetite, reduced sex drive, nausea, diarrhea, dizziness, or light-headedness.


Pregnancy/Breast-Feeding

There was no harm to the fetus when fluoxetine was given to pregnant laboratory animals, but there have been no studies of fluoxetine in pregnant women. Pregnant women are encouraged to discuss the benefits and potential risks of fluoxetine with their physician before deciding to use the drug.

HIV can be passed from a woman to her child through breast milk. In areas where nutritional alternatives are readily available, breast-feeding is discouraged for HIV-positive women. Fluoxetine is excreted in human milk. Because of the potential toxicity of the drug, women should consider alternatives to breast-feeding while taking it.

Use In Children

The safety and effective of fluoxetine for children has not been formally studied in clinical trials.


Use in the Elderly

It is not known if fluoxetine is metabolized differently in elderly people than in younger people. No unexpected side effects have been seen in elderly people taking 20 mg daily.


Drug Interactions

Extreme drowsiness may occur when fluoxetine is taken with alcohol or other central nervous system depressants such as barbiturates, muscle relaxants, sleeping pills, antihistamines, or tranquilizers.

Fluoxetine increases the blood-thinning effect of warfarin, which may require adjustment of warfarin dose. Similarly, fluoxetine may increase the effect of heart medicine such as digitoxin.

Serious side effects may occur when fluoxetine is taken with MAO inhibitors or when taken by people with residual levels of MAO inhibitors in their blood.

Fluoxetine can increase the levels of tryptophan and increase the chance of tryptophan-related side effects, including anxiety, agitation, restlessness, and stomach irritation.


Food Interactions

None reported.


Other Drugs Used for Similar Conditions

For treatment of depression, there are many options, including tricyclic antidepressants (desipramine, nortriptyline, protriptyline, amoxapine, maprotiline, imipramine, trimipramine, doxepin), MAO inhibitors (tranylcypromine, phenelzine, isocarboxazid), other serotonin reuptake inhibitors (paroxetine and sertraline), and stimulants such as methylphenidate. The appropriate drug varies from person to person and depends on age, physical health and condition, and other drugs being concurrently used.


Paroxetine

Brand Name (Manufacturer)

Paxil (Smithkline Beecham)


Type of Drug

Psychoactive-antidepressant


Used For

Paroxetine is primarily used for the treatment of mental depression. It is also used to treat obsessive-compulsive disorder.


General Information

Paroxetine, an antidepressant belonging to a class known as serotonin reuptake inhibitors, is chemically unrelated to tricyclic, tetracyclic, or other known classes of antidepressants. It has become widely used because it is effective and tends to have fewer side effects than older antidepressants. It is available in 20-mg and 30-mg tablets.

Antidepressant medications are usually taken over long periods. It generally takes ten days of treatment before steady levels of paroxetine are built up in the blood, and it may take that long for the drug to have an effect on depression. In some people, it may take considerably longer.

Paroxetine accumulates in the body's tissues with prolonged use, and the drug may stay in the body for weeks after discontinuing therapy. It is especially important to wait at least two weeks after stopping the drug before taking an antidepressant that is a monoamine oxidase (MAO) inhibitor (e.g., phenelzine or tranylcypromine). Similarly, paroxetine should not be taken for at least two weeks after a MAO inhibitor is used.

In prolonged use, tolerance to paroxetine may develop over time, and the drug may lose its effectiveness.


Treatment

The recommended initial dose is 20 mg taken once a day, usually in the morning. Some people who do not respond to this dose may respond to dose increases, in 10-mg-per-day increments, up to a maximum of 50 mg per day. The dose increases should occur no more often than once a week.

The recommended initial dose for the elderly, debilitated, and/or people with kidney or liver impairment is 10 mg per day. In these people, the daily dose may be increased as necessary but should not to exceed 40 mg.


Cautions and Warnings

Paroxetine should not be used by anyone with a known allergy to it. The drug is broken down by the liver and excreted by the kidneys. People with liver or kidney disease should take it with caution. In a small number of people who suffer from mania, paroxetine cause a reactivation of the condition. Paroxetine should be used with caution by people with a history of seizure disorders.


Side Effects

Twenty-one percent of volunteers in clinical trials of paroxetine quit using the drug because of side effects. The most common side effects include nausea, sleepiness, insomnia, increased sweating, tremors, anxiety, agitation, abnormal ejaculation, diarrhea, dry mouth, and vomiting. Less common side effects include flushing, increased salivation, cold or clammy skin, dizziness, blood pressure changes, swelling, coldness in the hands or feet, rapid heartbeat, weakness, loss of coordination, headaches, acne, hair loss, dry skin, difficulty swallowing, stomach gas, joint pains, muscle pains, cramps and weakness, abnormal thinking patterns, blurred vision, bleeding between periods, weight changes, and lymph swelling.


Pregnancy/Breast-Feeding

Paroxetine has not been formally studied in pregnant women. In animal studies, the drug did not cause fetal harm, but it is not known whether this would be true for humans. Pregnant women are encouraged to discuss the benefits and potential risks of paroxetine with their physician before deciding to use the drug.

HIV can be passed from a woman to her child through breast milk. In areas where nutritional alternatives are readily available, breast-feeding is discouraged for HIV-positive women. Paroxetine is excreted in human milk. Because of the potential toxicity of the drug, women are encouraged to consider alternatives to breast-feeding while using it.


Use In Children

Paroxetine is not recommended for children because its safety and effectiveness have not been formally studied or established for them.


Use in the Elderly

Paroxetine is metabolized more slowly in the elderly than in younger people, and their blood levels of the drug are higher for a given dosage. Consequently, elderly people often require lower doses of the drug.


Drug Interactions

Paroxetine combined with tryptophan may cause headache, nausea, sweating, and dizziness. It is recommended that the two drugs not be taken together. Serious and fatal reactions may occur if paroxetine and monoamine oxidase (MAO) inhibitors are taken together. Paroxetine may increasing the anticoagulant effect of warfarin. Cimetidine may increase paroxetine blood levels. Phenobarbital or phenytoin may decrease paroxetine blood levels.

Coadministration of paroxetine with nortriptyline, amitriptyline, imipramine, desipramine, fluoxetine, thioridazine, propafenone, flecainide, and encainide may require dose adjustments in either drug used in the combination. Paroxetine may decrease procyclidine blood levels.


Food Interactions

Paroxetine may be taken with or without food.


Other Drugs Used for Similar Conditions

A number of other drugs are available for the treatment of depression. Fluoxetine and sertraline are other serotonin reuptake inhibitors that are effective. Monoamine oxidase inhibitors that are useful as antidepressants are tranylcypromine, phenelzine, and isocarboxazid. Tricyclic antidepressants include amoxapine, desipramine, nortriptyline, amitriptyline, and doxepin.

Each person may react differently to different antidepressants. The choice of drug usually depends on the individual's response to the drug, the drug's effectiveness, and side effects. People who do not benefit from one type of antidepressant may respond to another.


Sertraline

Brand Name (Manufacturer)

Zoloft (Roerig)


Type of Drug

Psychoactive-antidepressant


Used For

Sertraline is widely used to treat the symptoms of mental depression. It is also used to treat obsessive-compulsive disorder.


General Information

Sertraline, an antidepressant, belongs to a class known as serotonin reuptake inhibitors. It is chemically unrelated to tricyclic, tetracyclic, or other known classes of antidepressants. It has become widely used because it is effective and tends to have fewer side effects than other older antidepressants. It is available in 50-mg and 100-mg tablets.

Antidepressant medications are usually taken over long periods. It takes a week or more before steady levels of sertraline are in the blood, and it may take as long for the drug to have an effect on depression. Sertraline accumulates in the body's tissues with prolonged use, and the drug may stay in the body for weeks after discontinuing therapy. It is especially important to wait at least two weeks after stopping sertraline before taking an antidepressant that is a monoamine oxidase (MAO) inhibitor (e.g., phenelzine or tranylcypromine). Similarly, sertraline should not be taken for at least two weeks after an MAO inhibitor is used.


Treatment

Sertraline is taken at a dose of 50 mg per day to start. If there is no response, the dose may gradually be increased up to 200 mg per day as tolerated and needed. Dose changes should not occur any more frequently than once a week. Lower doses of sertraline may be required in people with reduced liver function.


Cautions and Warnings

Sertraline should not be taken by anyone with a known allergy to it. The drug is broken down by the liver and excreted by the kidneys. People with liver or kidney disease should take it with caution. In a small number of people who suffer from mania, sertraline may worsen their condition.


Side Effects

The side effects that occur most frequently are dry mouth, headache, dizziness, tremors, nausea, diarrhea, fatigue, insomnia, difficulty ejaculating in men, and sleepiness. Each of the side effects occurred in more than 10% of people taking the drug in clinical trials.

Other side effects of sertraline include increased sweating, heart palpitations, twitching, rash, constipation, stomach upset, vomiting, changes in appetite, hot flushes, fever, increased thirst, agitation, nervousness, anxiety, impaired concentration, abnormal vision, menstrual disorders, back pain, ringing in the ears, and changes in taste.


Pregnancy/Breast-Feeding

Sertraline has not been formally studied in pregnant women. In animal studies, it did not cause fetal harm, but it is not known whether the same would be true for humans. Pregnant women are encouraged to discuss the benefits and potential risks of sertraline with their physician before deciding to use the drug.

HIV can be passed from a woman to her child through breast milk. In areas where nutritional alternatives are readily available, breast-feeding is discouraged for HIV-positive women. It is not known whether sertraline is excreted in human milk, but because of the potential toxicity of the drug for newborns, women are encouraged to consider alternatives to breast-feeding while using it.


Use In Children

Sertraline is not recommended for children because its safety and effectiveness have not been formally studied or established for them.


Use in the Elderly

Sertraline was studied in several hundred elderly people in clinical trials. In general, the side effects reported were similar to those seen in younger people. Sertraline is metabolized about 40% more slowly by elderly people, possibly because of the reduced liver and kidney function that occurs with aging. Because of this, it takes longer for sertraline to build up to steady levels in the blood of elderly people (two to three weeks compared to one week for younger people), which may mean it takes longer for the drug to work.


Drug Interactions

Sertraline may prolong the effects of diazepam and other benzodiazepines. Serious and fatal reactions may occur if sertraline and monoamine oxidase (MAO) inhibitors are taken together.

Sertraline may increase the effect of warfarin or digoxin, requiring dose adjustments of those two drugs. It may also affect blood levels of lithium and tolbutamide.


Food Interactions

Food increases the rate of uptake of sertraline into the body, and it may slightly increase the total amount of the drug absorbed. Nevertheless, the most consistent drug levels in the blood occur when sertraline is taken on an empty stomach.


Other Drugs Used for Similar Conditions

A number of other drugs are available for the treatment of depression. Fluoxetine and paroxetine are other serotonin reuptake inhibitors that are effective. MAO inhibitors that are useful as antidepressants are tranylcypromine, phenelzine, and isocarboxazid. Tricyclic antidepressants include amoxapine, desipramine, nortriptyline, amitriptyline, and doxepin.

Each person may react differently to different antidepressants. The choice of drug usually depends on the individual's response to the drug, the drug's effectiveness, and side effects. People who do not benefit from one type of antidepressant may respond to another.


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