Bupropion

Antidepressant Drug

Drug class: Atypical Antidepressants

Bupropion (WELLBUTRIN)（中文：安非他酮）

Common Strengths of Bupropion

Bupropion are available in the following strengths:

• Immediate-release: 75 mg, 100 mg
• Sustained-release (SR): 100 mg, 150 mg, 200 mg
• Extended-release (XL): 150 mg, 300 mg, 450 mg

Drug Trade Names of Bupropion

• Wellbutrin
• Wellbutrin SR
• Wellbutrin XL
• Zyban

Drug Usage

• Major depressive disorder (MDD)
• Seasonal affective disorder (SAD): Bupropion is used to manage seasonal patterns of depression.
• Smoking cessation: Under the brand name Zyban, it helps reduce nicotine cravings and withdrawal symptoms.

Mechanism of Action

Bupropion is a norepinephrine-dopamine reuptake inhibitor (NDRI). It works by inhibiting the reuptake of norepinephrine and dopamine, two neurotransmitters involved in mood regulation and reward pathways. By preventing their reabsorption, bupropion increases the levels of these neurotransmitters in the brain, which can help alleviate symptoms of depression and aid in smoking cessation.

Route of Administration

Oral

Dosages

Major depressive disorder (MDD):

• Immediate-release: 100 mg twice daily, up to 450 mg/day
• Sustained-release: 150 mg twice daily, up to 400 mg/day
• Extended-release: 150 - 300 mg once daily, up to 450 mg/day

Renal dose based on eGFR:

• eGFR 30 - 89 mL/min: Reduce dose by 25 - 50%
• eGFR <30 mL/min: Reduce dose by 50% or more

Side Effects

Frequency	Adverse reactions
Common	These side effects are generally not severe and may diminish as your body adjusts to the medication.
	Dry mouth: Chew sugar-free gum or sweets.
	Constipation: Increase fiber intake and drink plenty of water
	Dizziness: Change sitting or standing position slowly
	Nausea: Stick to simple meals and avoid rich or spicy foods
	Increased sweating: Wear loose clothing and use a fan if needed
	Tremors or shaking
	Insomnia: Take in the morning
	Blurred vision
	Ringing in the ears (tinnitus)
	Agitation
	Restlessness
	Anxiety
Serious	Serious side effect of bupropion require immediate medical attention. These include:
	Seizures: Bupropion can lower the seizure threshold, especially at higher doses.
	Severe allergic reaction: Symptoms can include hives, itching, fever, swollen glands, difficulty breathing, and swelling of the face or throat.
	Mental health effects: These can include new or worsening depression, suicidal thoughts or behaviors, panic attacks, agitation, aggression, hostility, and other unusual changes in behavior or mood.
	Cardiovascular issues: Fast or irregular heartbeats, chest pain, and high blood pressure.
	Eye problems: Pain, swelling, redness, or vision changes such as blurred or double vision.
	Severe skin reactions: Rash, blisters, peeling skin, and other severe skin reactions.
	Manic episodes: Symptoms include excessively high energy, severe trouble sleeping, racing thoughts, reckless behavior, and unusually grand ideas.

Pharmacokinetics

• Extensively metabolized by CYP2B6 in the liver
• Elimination half-life: approximately 10 - 20 hours

The full therapeutic effects of bupropion can take 4 to 6 weeks to manifest.

Bupropion's pharmacokinetic profile is characterized by rapid absorption, extensive metabolism, and a significant presence of active metabolites.

Drug Precautions

Pregnancy

Use with caution; potential risks to the fetus

Breastfeeding

Use with caution; bupropion is ecreted in breast milk

Children and Elderly

• Not recommended for children under 18 for depression
• Elderly may require lower doses due to decreased clearance

Monitoring Requirements

• Blood pressure
• Signs of suicidal thoughts or behaviors
• Seizure risk
• Liver function

Drug Interaction

• Major Drug Interactions
  • Bupropion is primarily metabolized by CYP2B6, so inhibitors or inducers of this enzyme can significantly affect bupropion levels. Examples of CYP2B6 inhibitors include ticlopidine and clopidogrel.
  • Bupropion is a moderate inhibitor of CYP2D6, so it can increase levels of medications metabolized by this enzyme like venlafaxine, desipramine, and metoprolol.
  • Combining bupropion with other antidepressants like SSRIs like fluoxetine (Prozac) and sertraline (Zoloft), venlafaxine or duloxetine may increase the risk of serotonin syndrome, especially in poor CYP2D6 metabolizers.
  • Bupropion can lower the seizure threshold, so it should be avoided in patients with seizure disorders or eating disorders like bulimia or anorexia that increase seizure risk.
  • Drinking alcohol while taking bupropion may increase the risk of seizures. Alcohol should be limited or avoided.
  • Antipsychotics: Drugs like thioridazine can interact with bupropion, increasing the risk of side effects such as seizures and cardiovascular issues.
  • Tamoxifen: Bupropion can reduce the effectiveness of tamoxifen, a medication used in breast cancer treatment.

FAQ

How Should I Take the Tablet?

Take the tablet whole with or without food. Do not crush, chew, or split extended-release tablets

What Should I Avoid While Taking?

Avoid alcohol consumption and operating heavy machinery until you know how bupropion affects you.

What Happens if I Miss a Dose?

Take the missed dose as soon as you remember unless it is almost time for your next dose. Do not double doses.