What are the side effects of topiramate?

Side Effects of Topiramate

Topiramate has numerous potential side effects ranging from common cognitive issues to serious metabolic complications, with the most common side effects including paresthesias, dizziness, dysguesia, insomnia, constipation, and dry mouth. 1

Common Side Effects

• Neurological effects:

  • Paresthesias (tingling of arms and legs) 2
  • Dizziness 1
  • Dysguesia (altered taste) 1
  • Insomnia 1
  • Cognitive impairment (problems with concentration, attention, memory, speech) 2
  • Confusion 2
  • Somnolence/sleepiness 2
  • Loss of muscle coordination 2

• Gastrointestinal effects:

  • Constipation 1
  • Dry mouth 1
  • Nausea 2
  • Loss of appetite 2
  • Diarrhea 2
  • Weight loss 2

• Psychological effects:

  • Depression or mood problems 2
  • Nervousness 2
  • Aggression 2
  • Irritability 1

Serious Side Effects

1. Metabolic acidosis:

   • Occurs when there is too much acid in the blood 2
   • Symptoms include tiredness, loss of appetite, irregular heartbeat, impaired consciousness 2
   • Requires monitoring of serum bicarbonate levels 1
   • Can be severe in adults and children 3

2. Eye problems:

   • Acute myopia (sudden decrease in vision) 2
   • Secondary angle closure glaucoma (increased eye pressure) 2
   • Can lead to blindness if not treated promptly 2

3. Decreased sweating (oligohidrosis) and increased body temperature:

   • Particularly concerning in hot temperatures 2
   • May require hospitalization 2

4. Kidney stones:

   • Due to carbonic anhydrase inhibitor properties 1
   • Risk increases with higher doses and prolonged exposure 1
   • Preventable by drinking plenty of fluids 2

5. High blood ammonia levels:

   • Can affect mental activities and decrease alertness 2
   • May cause fatigue or vomiting 2
   • More common when used with valproic acid 2

6. Pregnancy risks:

   • Potential increased risk of orofacial clefts in infants exposed during first trimester 1
   • FDA requires Risk Evaluation and Mitigation Strategy for women of reproductive potential 1

Special Considerations

Dosing and Administration

• Topiramate should be taken exactly as prescribed 2
• Can be taken before, during, or after meals 2
• Requires gradual dose titration when starting and stopping 2

Monitoring Requirements

• Regular monitoring of serum bicarbonate levels for long-term use 1
• Monthly pregnancy tests for women of reproductive potential 1
• Blood pressure and heart rate monitoring 1

Drug Interactions

• Reduced efficacy of oral contraceptives 1
• May interact with other central nervous system depressants 2
• Avoid alcohol while taking topiramate 2

Contraindications

• Should be avoided in patients with:
  • History of significant nephrolithiasis 1
  • Uncontrolled hypertension 1
  • History of cardiovascular disease 1
  • Untreated hyperthyroidism 1

Rare but Reported Side Effects

• Urinary incontinence 4
• Upper respiratory tract infection 2

Practical Advice

• Take early in the day to minimize insomnia 1
• Drink plenty of fluids to prevent kidney stones 2
• Do not drive or operate machinery until you know how topiramate affects you 2
• Do not abruptly discontinue the medication; taper slowly under medical supervision 2

By understanding these potential side effects, patients and healthcare providers can better monitor for complications and take appropriate steps to minimize risks while using topiramate.