Lyrica vs Gabapentin: A Family Doctor’s Perspective
August 12, 2011 Dr. Pullen
After at first being a skeptic I am finding a significant role for Lyrica in treatment of neuropathic pain syndromes. Lyrica first came to market in December of 2004 in the US with approval for diabetic neuropathic pain and post herpetic neuralgic pain. I was a slow adopter of this drug. It seemed essentially a high priced alternative to Neurontin, a closely related drug that is used off label for the same indications. It appeared another case of a drug company miraculously coming up with a new and improved version of an old drug shortly before the patent on the old drug expires as I’ve previously discussed with Nexium and Lexapro. (Pfizer markets gabapentin as Neurontin and also pregabalin as Lyrica) Lyrica is pregabalin which is chemically very similar to gabapentin and works by the same mechanism.
Over time I have come to realize that Lyrica does have some distinct advantages over gabapentin. From a practical standpoint the biggest advantage of Lyrica over gabapentin is that I can prescribe a dose of Lyrica that has a chance of working for their painful condition without intolerable Lyrica side effects at the starting dose. The lowest dose of gabapentin that is typically effective for neuropathic pain is 1800 mg daily. Starting a patient at that dose will almost always lead to intolerable drowsiness and an intoxicated sensation of disequilibrium and confusion. We have to start gabapentin with a slow taper up in dosing to avoid these intolerable side effects. A typical starting regimen would be to start on gabapentin 100 mg three times a day, or 300 mg at bedtime for a few days and then very gradually increase the dose over a couple of weeks or more to a dose of 600 mg three times daily. Most patients do not get adequate pain relief at doses much lower than 1800 mg daily of gabapentin. Increasing the dose much faster almost guarantees the patient stopping therapy due to these side effects. Using Lyrica I can prescribe 50-75 mg twice daily from the beginning with a good chance that the starting dose will help with the pain. If it takes a higher dose the Lyrica can be increased much faster than gabapentin without causing undue sedation and drugged feeling in most patients.
Other advantages of Lyrica over gabapentin include the faster and more consistent absorption from the gut. About 90% of Lyrica is absorbed from the gut vs. 27-60% of gabapentin being absorbed. In addition the absorption of Lyrica is not dose dependent whereas the higher the dose of gabapentin the lower the absorption rate. Both Lyrica and gabapentin work via a similar mechanism biologically.
For conditions like diabetic peripheral neuropathy I find gabapentin to be a good option. These patients have a chronic condition that has usually been slowly progressive, and gradually beginning a medication with the expectation of help over a few weeks time is acceptable to most of these patients. For more acutely painful conditions like herpes zoster and trigeminal neuralgia the idea of taking up to several weeks for pain relief is much less acceptable. In these conditions Lyrica is far more attractive.
Lyrica was also the first drug with an FDA approval specifically for treating fibromyalgia. Gabapentin is also used off label (without a specific FDA indication for the condition being treated) for fibromyalgia. It is nice as a physician to have a drug with a proven benefit for fibromyalgia as it is a notoriously difficult to treat problem. I have had a couple of patients who have had dramatic improvement of their fibromyalgia on Lyrica and have not had this type of response with gabapentin. I expect that once Lyrica loses its patent and becomes competitive with gabapentin as a generic medication it will nearly replace gabapentin as the drug of choice or treatment of neuropathic pain. For reasons unknown to me gabapentin has not come down dramatically in price like nearly every other generic drug. The cash price of gabapentin 300 mg capsules at Costco is still 14.68/ 100 capsules of the generic product, making the cost of 600 mg three times daily $26.42/ month. This compares favorably though to brand name Neurontin at $391.63 for the same dose or Lyrica 75 mg twice daily of $172.95 / month. My experience has also been that it is difficult to receive authorization from third party payers for Lyrica without previously trying gabapentin, even when gabapentin does not have FDA approval for the condition being treated.
In summary I still use generic gabapentin frequently, and find it a very good drug, but I find that Lyrica sometimes works when gabapentin seems not to be effective and that Lyrica is frequently better tolerated by patients. Especially for patients with fibromyalgia Lyrica is sometimes a remarkably effective drug when not much else seems to work.
ray, just another market for Nuuedexta. I'll have to post twice:
Applies to pregabalin: oral capsule, oral solution
Nervous system side effects including dizziness (up to 38%), somnolence (up to 28%), ataxia (up to 20%), tremor (up to 11%), neuropathy (up to 9%), abnormal thinking (up to 9%), abnormal gait (up to 5%), confusion (up to 7%), speech disorder (up to 7%), amnesia (up to 6%), incoordination (up to 6%), twitching (up to 5%), vertigo (up to 4%), myoclonus (up to 4%), euphoria (up to 3%), and nervousness (up to 1%) have been reported. Anxiety, depersonalization, hypertonia, hypesthesia, decreased libido, nystagmus, paresthesia, stupor, and twitching have been reported frequently. Abnormal dreams, agitation, apathy, aphasia, circumoral paresthesia, dysarthria, hallucinations, hostility, hyperalgesia, hyperesthesia, hyperkinesia, hypokinesia, hypotonia, increased libido, myoclonus, and neuralgia have been reported infrequently. Addiction, cerebellar syndrome, cogwheel rigidity, coma, delirium, delusions, dysautonomia, dyskinesia, dystonia, encephalopathy, extrapyramidal syndrome, Guillain-Barre syndrome, hypoalgesia, intracranial hypertension, manic reaction, paranoid reaction, peripheral neuritis, psychotic depression, schizophrenic reaction, torticollis, and trismus have been reported rarely.
Metabolic side effects including peripheral edema (up to 16%), weight gain (up to 16%), edema (up to 6%), and hypoglycemia (up to 3%) have been reported. Decreased glucose tolerance and urate crystalluria have been reported rarely.
Gastrointestinal side effects including dry mouth (up to 15%), constipation (up to 7%), increased appetite (up to 6%), vomiting (up to 3%), flatulence (up to 3%), nausea and diarrhea have been reported. Gastroenteritis has been reported frequently. Cholecystitis, cholelithiasis, colitis, dysphagia, esophagitis, gastritis, gastrointestinal hemorrhage, melena, mouth ulceration, pancreatitis, rectal hemorrhage, and tongue edema have been reported infrequently. Aphthous stomatitis and esophageal ulcer have been reported rarely.
General side effects including infection (up to 14%), accidental injury (up to 11%), headache (up to 9%), asthenia (up to 7%), pain (up to 5%), chest pain (up to 4%), facial edema (up to 3%), flu syndrome (up to 2%), and back pain (up to 2%) have been reported. Abdominal pain and fever have been reported frequently. Abscess, cellulitis, chills, malaise, neck rigidity, overdose, pelvic pain, photosensitivity reaction, and suicide attempt have been reported infrequently. Ascites, granuloma, hangover effect, intentional injury, retroperitoneal fibrosis, shock, and suicide have been reported rarely.
Ocular side effects including visual field changes (13%), reduced visual acuity (7%), and blurred vision (6%) have been reported. Conjunctivitis and diplopia have been reported frequently. Abnormality of accommodation, blepharitis, dry eyes, eye hemorrhage, hyperacusis, photophobia, retinal vascular disorder, and retinal edema have been reported infrequently. Anisocoria, blindness, corneal ulcer, exophthalmos, extraocular palsy, iritis, keratitis, keratoconjunctivitis, miosis, mydriasis, night blindness, ophthalmoplegia, optic atrophy, papilledema, parosmia, ptosis, and uveitis have been reported rarely.
Blurred vision resolved in the majority of cases with continued dosing. Less than 1% of patients discontinued pregabalin treatment due to vision related events (primarily blurred vision).
Patients should be informed that they should notify their physician if changes in vision occur. If visual disturbance persists, further assessment should be considered. Furthermore, more frequent assessment should be considered for patients who are already routinely monitored for ocular conditions.
In a cohort study of 333 diabetic patients who received pregabalin (the active ingredient contained in Lyrica) for at least 2 years, the average weight gain was 5.2 kg. Pregabalin associated weight gain was related to dose and duration or exposure.
Other side effects including weight gain have been reported. In controlled clinical trials of up to 13 weeks, weight gain of 7% or more over baseline has been reported in 8% of pregabalin-treated patients. Otitis media and tinnitus have been reported frequently. Taste loss, and taste perversion have been reported infrequently.
Cardiovascular side effects including edema, primarily peripheral edema (6%) have been reported. Deep thrombophlebitis, heart failure, hypotension, syncope, and postural hypotension have been reported infrequently. Depressed ST and ventricular fibrillation have been reported rarely. There have been postmarketing reports of angioedema and headache.
Specific symptoms of angioedema have included swelling of the face, mouth (tongue, lips, and gums), and neck (throat and larynx). There have also been reports of life-threatening angioedema with respiratory compromise requiring emergency treatment. Pregabalin should be discontinued immediately in patients with these symptoms. Caution is recommended if prescribing pregabalin to patients who have had a previous episode of angioedema. In addition, patients who are taking other drugs associated with angioedema (e.g., angiotensin converting enzyme inhibitors [ACE inhibitors]) may be at increased risk of developing angioedema.
Respiratory side effects including dyspnea (up to 3%) and bronchitis (up to 3%) have been reported. Apnea, atelectasis, bronchiolitis, hiccup, laryngismus, lung edema, lung fibrosis, and yawn have been reported rarely.
Genitourinary side effects including urinary incontinence (up to 2%) have been reported. Anorgasmia, impotence, and urinary frequency have been reported frequently. Abnormal #$%$, albuminuria, amenorrhea, dysmenorrhea, dysuria, hematuria, kidney calculus, leukorrhea, menorrhagia, metrorrhagia, nephritis, oliguria, and urinary retention have been reported infrequently. Acute kidney failure, balanitis, bladder neoplasm, cervicitis, dyspareunia, epididymitis, female lactation, and glomerulitis have been reported rarely. Unilateral painful gynecomastia has been reported postmarketing.
Musculoskeletal side effects including myasthenia (1%) have been reported. Arthralgia, leg cramps, myalgia, and myasthenia have been reported frequently. Arthrosis has been reported infrequently. Generalized spasm has been reported rarely.
Oncologic side effects including an unexpectedly high incidence of hemangiosarcoma have been reported in animal studies after pregabalin (the active ingredient contained in Lyrica) was given their diet for two years. In clinical studies comprised of 6,396 patient-years of exposure, new or worsening-preexisting tumors were reported in 57 patients. It is not known if the incidence seen in these clinical studies is or is not affected by treatment.
Hypersensitivity side effects including allergic reactions have been reported frequently. Allergic reactions have included skin redness, blisters, hives, rash, dyspnea, and wheezing. Pregabalin (the active ingredient contained in Lyrica) should be discontinued immediately in patients with these symptoms. Anaphylactoid reactions have been reported rarely.
Hematologic side effects including ecchymosis have been reported frequently. Anemia, eosinophilia, hyperchromic anemia, leukocytosis, leukopenia, lymphadenopathy, and thrombocytopenia have been reported infrequently. Myelofibrosis, polycythemia, decreased prothrombin, purpura, and thrombocytopenia have been reported rarely.
Dermatologic side effects including pruritus have been reported frequently. Alopecia, dry skin, eczema, hirsutism, skin ulcer, urticaria, and vesiculobullous rash have been reported infrequently. Angioedema, exfoliative dermatitis, lichenoid dermatitis, melanosis, petechial rash, purpuric rash, pustular rash, skin atrophy, skin necrosis, skin nodule, Stevens-Johnson syndrome, and subcutaneous nodule have been reported rarely.
Another one of your safe drugs!