Paxil
Paxil (generic name: Paroxetine) is an anti-depressant drug that affects the chemicals that nerves in the brain use to communicate with one another. These chemical messengers, called neurotransmitters, are released by one nerve and taken up by other nerves. Neurotransmitters that are released but not taken up by other nerves are taken up by the nerves that release them (”reuptake”). Many experts believe that it is an imbalance among the amounts of the different neurotransmitters that are released that causes depression. Paroxetine works by inhibiting the reuptake of serotonin by the nerves that release it, an action which allows more serotonin to be available to be taken up by other nerves. Paroxetine is in a class of drugs called selective serotonin reuptake inhibitors (SSRIs), a class that also contains fluoxetine (Prozac) and sertraline (Zoloft).
All SSRIs, including paroxetine, should not be taken with any of the MAO (mono-amine oxidase) inhibitor-class of anti-depressants, for example, isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Parnate), and procarbazine (Matulane). Such combinations may lead to confusion, high blood pressure, tremor, and increased activity. This same type of interaction may also occur with selegiline (Eldepryl), fenfluramine (Pondimin), and dexfenfluramine (Redux). The anti-ulcer medication, cimetidine (Tagamet) can increase the amount of paroxetine in the blood, possibly leading to side effects. Paroxetine may increase the risk of bleeding in patients taking warfarin (Coumadin) although the mechanism for the interaction is not known. Tryptophan can cause headaches, nausea, sweating, and dizziness when taken with any SSRI. Phenytoin (Dilantin) and phenobarbital may decrease the amount of paroxetine in the body and possibly reducing its effectiveness.
Paxil CR is approved for continuous or intermittent therapy for premenstrual dysphoric disorder. For intermittent therapy, women take Pacil CR once daily during only the two-week period prior to the onset of their menstrual cycle rather than throughout the month.
Paxil side effects
The most commonly noted side effects associated with paxil are anxiety, sweating, nausea, decreased appetite, somnolence (sleepiness), dizziness, insomnia, and male sexual disturbances. Dry mouth occurs in about 18% of patients taking paroxetine.
The withdrawal of treatment with many anti-depressants has been associated with troublesome symptoms. Symptoms have been particularly frequent with anti-depressants, like paroxetine, classified as SSRI’s. Specifically, the incidence of symptoms upon withdrawal is between 17% and 30% with paroxetine and fluvoxamine (Luvox), but less than 5% with other SSRI’s.
The most common symptoms of withdrawal have been dizziness, tiredness, tingling of the extremities, nausea, vivid dreams, irritability, and poor mood. Other symptoms have included visual disturbances and headaches.
Withdrawal reactions have been reported upon withdrawing SSRI’s after an average of 12 to 36 weeks of treatment, but after as few as 5 weeks. Although most authorities have recommended that treatment be discontinued by tapering the SSRI (by gradually reducing the dose), symptoms have occurred despite tapering. Symptoms generally appear within a few days of discontinuing medication and persist for an average of 12 days (up to 21 days). They are relieved within 24 hours by re-administering the medication that was discontinued.