How Long Until It Works

• Can reduce neuropathic pain and anxiety within a week

• Should reduce seizures by 2 weeks

• If it is not producing clinical benefits within 6–8 weeks, it may require a dosage increase or it may not work at all

If It Works

• The goal of treatment of neuropathic pain, seizures, and anxiety disorders is to reduce symptoms as much as possible, and if necessary in combination with other treatments

• Treatment of neuropathic pain most often reduces but does not eliminate all symptoms and is not a cure since symptoms usually recur after medicine stopped

• Continue treatment until all symptoms are gone or until improvement is stable and then continue treating indefinitely as long as improvement persists

If It Doesn’t Work (for neuropathic pain)

• Many patients have only a partial response where some symptoms are improved but others persist

• Other patients may be nonresponders, sometimes called treatment-resistant or treatment-refractory

• Consider increasing dose, switching to another agent or adding an appropriate augmenting agent

• Consider biofeedback or hypnosis for pain

• Consider psychotherapy for anxiety

• Consider the presence of noncompliance and counsel patient

• Consider evaluation for another diagnosis or for a comorbid condition (e.g., medical illness, substance abuse, etc.)

Best Augmenting Combos for Partial Response or Treatment Resistance

✽ In addition to being a first-line treatment for neuropathic pain and anxiety disorders, pregabalin is itself an augmenting agent to numerous other anticonvulsants in treating epilepsy

• For postherpetic neuralgia, pregabalin can decrease concomitant opiate use

✽ For neuropathic pain, tricyclic antidepressants and SNRIs as well as tiagabine, other anticonvulsants, and even opiates can augment pregabalin if done by experts while carefully monitoring in difficult cases

• For anxiety, SSRIs, SNRIs, or benzodiazepines can augment pregabalin

Tests

• None for healthy individuals

PREGABALIN: SIDE EFFECTS

How Drug Causes Side Effects

• CNS side effects may be due to excessive blockade of voltage-sensitive calcium channels

Notable Side Effects

✽ Sedation, dizziness

• Ataxia, fatigue, tremor, dysarthria, paresthesia, memory impairment, coordination abnormal, impaired attention, confusion, euphoric mood, irritability

• Vomiting, dry mouth, constipation, weight gain, increased appetite, flatulence

• Blurred vision, diplopia

• Peripheral edema

• Libido decreased, erectile dysfunction

Life-Threatening or Dangerous Side Effects

• Rare activation of suicidal ideation and behavior (suicidality)

Weight Gain

• Occurs in significant minority

Sedation

• Many experience and/or can be significant in amount

• Dose-related

• Can wear off with time

What to Do About Side Effects

• Wait

• Wait

• Wait

• Take more of the dose at night to reduce daytime sedation

• Lower the dose

• Switch to another agent

Best Augmenting Agents for Side Effects

• Many side effects cannot be improved with an augmenting agent

PREGABALIN: DOSING AND USE

Usual Dosage Range

• 150–600 mg/day in 2–3 doses

Dosage Forms

• Capsule 25 mg, 50 mg, 75 mg, 100 mg, 150 mg, 200 mg, 225 mg, 300 mg

How to Dose

• Neuropathic pain: initial 150 mg/day in 2–3 doses; can increase to 300 mg/day in 2–3 doses after 7 days; can increase to 600 mg/day in 2–3 doses after 7 more days; maximum dose generally 600 mg/day (may be lower for diabetic peripheral neuropathy and fibromyalgia)

• Seizures: initial 150 mg/day in 2–3 doses; can increase to 300 mg/day in 2–3 doses after 7 days; can increase to 600 mg/day in 2–3 doses after 7 more days; maximum dose generally 600 mg/day