What are the potential side effects of Vyvanse (lisdexamfetamine) in patients, particularly those with pre-existing cardiovascular conditions or anxiety?

Side Effects of Vyvanse (Lisdexamfetamine)

Vyvanse causes common side effects including decreased appetite, insomnia, dry mouth, anxiety, and increased heart rate, with cardiovascular effects being particularly important to monitor in patients with pre-existing heart conditions or anxiety disorders. 1

Most Common Side Effects (≥5% incidence, at least twice placebo rate)

In Adults with ADHD:

• Decreased appetite (27%) - most frequent side effect 1
• Insomnia (27%) - equally common, can be managed by morning dosing 1
• Dry mouth (26%) 1
• Anxiety (6%) 1
• Diarrhea (7%) and nausea (7%) 1
• Anorexia (5%) 1
• Feeling jittery (4%) 1

In Pediatric Patients (ages 6-17):

• Decreased appetite (34% in ages 6-12) 1
• Insomnia (13% in ages 6-12) 1
• Upper abdominal pain 1
• Irritability 1
• Vomiting 1

Cardiovascular Side Effects - Critical for Pre-existing Conditions

Blood Pressure and Heart Rate Changes:

• Increased heart rate by 2.8-5.2 bpm depending on dose (30-70 mg/day) 2
• Increased blood pressure (3% incidence) 1
• Palpitations (2%) and tachycardia 1
• Pulse outliers (≥100 bpm) occurred in 3.3-8.5% of subjects 2

Important Cardiovascular Considerations:

Patients with pre-existing cardiovascular disease require careful monitoring, as the American Heart Association and American Academy of Pediatrics recommend regular blood pressure and pulse monitoring, especially during initial titration. 3 Vyvanse should be avoided in patients with serious cardiac disease, uncontrolled hypertension, or tachyarrhythmias 4, 1. A 6-month cardiopulmonary study found no clinically meaningful changes in cardiac structure or function at maximum exertion, though resting changes in left ventricular dimensions were noted 5.

Psychiatric Side Effects - Critical for Anxiety Disorders

Anxiety and Agitation:

• Anxiety (6% in adults, 0% in placebo) 1
• Agitation (3%) 1
• Irritability (2%) - led to discontinuation in some cases 1
• Restlessness (3%) 1

Patients with pre-existing anxiety disorders require particularly careful monitoring, as stimulants can exacerbate anxiety symptoms. 4 The medication should be initiated at lower doses in anxious patients, with close monitoring for worsening symptoms 3.

Weight and Growth Effects

In Pediatric Patients:

• Mean weight loss of 0.9-2.5 pounds after 4 weeks (dose-dependent: 30-70 mg) 1
• Age- and sex-normalized mean change in weight percentile of -13.4 over 1 year in consistently medicated children 1
• Growth rate slowing documented, with approximately 2 cm less height growth over 3 years 1

In Adults:

• Mean weight loss of 2.8-4.3 pounds after 4 weeks (dose-dependent) 1
• Weight loss of 4% reported in binge eating disorder trials 1

Discontinuation Rates Due to Side Effects

ADHD Trials:

• Pediatric patients (ages 6-12): 8% discontinued vs 0% placebo 1
• Adolescents (ages 13-17): 3% discontinued vs 1% placebo 1
• Adults: 6% discontinued vs 2% placebo 1

Most common reasons for discontinuation in adults included insomnia (2%), tachycardia (1%), hypertension (1%), and anxiety (1%) 1.

Sexual Side Effects (Adults Only)

• Erectile dysfunction in 2.6% of males (0% placebo) 1
• Decreased libido in 1.4% (0% placebo) 1

Serious but Rare Side Effects

Postmarketing Reports:

• Cardiomyopathy 1
• Serotonin syndrome (especially with concomitant serotonergic drugs) 1
• Seizures 1
• Peripheral vasculopathy including Raynaud's phenomenon 1
• Rhabdomyolysis 1
• Stevens-Johnson Syndrome 1
• Anaphylactic reactions 1

Contraindications and High-Risk Situations

Vyvanse is absolutely contraindicated with monoamine oxidase inhibitors (MAOIs) due to risk of hypertensive crisis. 1 Allow at least 14 days between MAOI discontinuation and Vyvanse initiation 4, 1. The medication should be avoided in patients with hyperthyroidism, glaucoma, agitated states, and history of drug abuse 4.

Monitoring Recommendations

Regular monitoring of blood pressure, heart rate, and weight is essential at each visit. 3 Dose reduction should be considered if significant cardiovascular elevations occur 3. In pediatric patients, systematic evaluation of growth parameters (height and weight) should be conducted at each visit 3, 1.

Tolerability Profile

The overall tolerability profile of Vyvanse is similar to other amphetamine-based stimulants, with most adverse events being mild to moderate in intensity 6, 7, 8. The prodrug design provides a more gradual onset of action compared to immediate-release amphetamines, which may reduce abuse potential 8.