What is the drug class of bupropion, particularly for a patient with a history of depression, anxiety, and sexual dysfunction as a side effect of venlafaxine (Effexor)?

Bupropion Drug Class

Bupropion is a norepinephrine-dopamine reuptake inhibitor (NDRI), making it uniquely different from SSRIs and particularly advantageous for patients experiencing sexual dysfunction from other antidepressants like venlafaxine. 1, 2

Mechanism of Action

• Bupropion acts via dual inhibition of norepinephrine and dopamine reuptake and is devoid of clinically significant serotonergic effects or direct effects on postsynaptic receptors 2
• This selective norepinephrine and dopamine reuptake inhibition mechanism distinguishes it from SSRIs (which target serotonin), SNRIs like venlafaxine (which target both serotonin and norepinephrine), and tricyclic antidepressants 2

Clinical Advantages for Sexual Dysfunction

Bupropion has significantly lower rates of sexual adverse events compared to SSRIs, making it the optimal choice for patients experiencing sexual dysfunction from medications like venlafaxine. 1, 3

• In a large cross-sectional study, bupropion SR was associated with only 25% prevalence of sexual dysfunction, compared to 36-43% with SSRIs and venlafaxine XR 3
• In a prospectively defined subpopulation, the odds of having sexual dysfunction were 4 to 6 times greater with SSRIs or venlafaxine XR than with bupropion SR 3
• Bupropion is the only antidepressant that has been shown to consistently promote weight loss rather than weight gain, another advantage over venlafaxine 1

Important Contraindications and Warnings

Seizure Risk

• Bupropion is contraindicated in patients with seizure disorders, brain metastases, or conditions that increase seizure risk (severe head injury, arteriovenous malformation, CNS tumor, anorexia nervosa, bulimia) 4
• The dose should not exceed 300 mg once daily, and the dose must be increased gradually to minimize seizure risk 4

Bipolar Disorder and Mania Risk

• Bupropion is "activating" and can exacerbate anxiety or trigger manic episodes in patients with bipolar disorder 1, 5
• If used in bipolar depression, it must always be combined with adequate mood stabilizer therapy (lithium, valproate, or carbamazepine at therapeutic levels) with intensive monitoring for manic symptoms 5
• Screen all patients for history of bipolar disorder and risk factors before initiating treatment 4

Cardiovascular Monitoring

• Monitor blood pressure and heart rate, particularly during the first 12 weeks of treatment, as bupropion can cause tachycardia and elevated blood pressure 6, 4
• Bupropion is contraindicated in patients with uncontrolled hypertension 6
• In clinical trials, 1-2% of patients discontinued due to hypertension 4

FDA-Approved Indications

• Major depressive disorder 4, 7
• Smoking cessation (as bupropion SR formulation) 1
• Seasonal affective disorder 4
• Chronic weight management (in combination with naltrexone as Contrave) 1

Practical Dosing Considerations

• Available as immediate release (IR, three times daily), sustained release (SR, twice daily), and extended release (XR, once daily) formulations 7
• Administer the second dose of bupropion SR before 3 PM to minimize insomnia risk 6
• Start at 150 mg once daily for 3 days, then increase to 150 mg twice daily if tolerated 1
• Maximum dose is 300 mg per day for extended release formulations 4

Clinical Context for Your Patient

For a patient with depression, anxiety, and sexual dysfunction from venlafaxine, bupropion represents an excellent alternative given its lack of serotonergic effects and minimal sexual side effects 1, 2. However, the "activating" nature of bupropion requires careful assessment: if the patient has significant anxiety symptoms, this could be exacerbated 1. Additionally, rule out any history of bipolar disorder, seizures, or uncontrolled hypertension before prescribing 5, 4.