The main factors affecting the bupropion dose used are tolerance, response and the clinical indication for which it is being used. Other factors which may be taken into account include the liver and kidney function of the patient which, if compromised, may necessitate a lower dosage. There are a number of different pharmaceutical preparations of bupropion available — immediate-release, slow-release and extended-release — and which one is used will determine the frequency of dosage of the drug.
Bupropion is an antidepressant drug which is used to treat depression, seasonal affective disorder and in the cessation of smoking. It works by blocking the reuptake of noradrenaline and dopamine in the brain, which are chemical neurotransmitters involved with mood. Bupropion may be known by different trade names in different countries, according to manufacturer, and in most countries is available by prescription only.
The sufficient bupropion dose for depression will be established by the treating doctor on a case-by-case basis. Usually the drug is started at low dose and increased slowly with the doctor monitoring response and tolerance. The bupropion dose will usually be taken three times a day for the immediate-release preparation, twice a day for the sustained release preparation and once daily for the extended-release preparation. The prescribed dose should never be exceeded without discussion with the doctor.
When using the drug to aid stopping smoking, the bupropion dose is usually started as a once daily dose and increased to twice daily after some days. The drug is started while the person is still smoking but a quitting date is established before taking the first bupropion dose, usually within a week or two of starting treatment. The full course of treatment is usually two to three months and should be accompanied by non-drug supportive measures.
In patients who have hepatic (liver) dysfunction, bupropion may be contraindicated or a reduced bupropion dose or increased time between dosing may be necessary. Any underlying clinical conditions and other medications, including homeopathic, complementary and over-the-counter medications, should be discussed with the prescribing doctor before starting treatment. Interactions may occur between bupropion and other medicines.
As with any medication, adverse effects may occur. These may include agitation, insomnia, headache and nausea. Seizures have also been reported, so bupropion is contraindicated in patients with pre-existing seizure disorders. The lowest effective dose will be used to minimize the possibility of adverse effects and medical advice should be sought if they do occur.