LYRICA SIDE EFFECTS AND INDICATIONS |
LYRICA INDICATIONS In June, 2005, Lyrica was approved by FDA for a new use which is to treat partial onset seizures in adults with epilepsy. Pregabalin (Lyrica) was approved by FDA for the management of diabetic peripheral neuropathy and postherpetic neuralgia in December 2004. PREGABALIN (LYRICA) CLINICAL TRIALS Pregabalin (Lyrica) was tested in three trials including nearly 1,000 patients. Before the treatment with pregabalin (Lyrica), patients had approximately 10 seizures a month, even though they were taking one to three other antiepileptic medications. During the Pregabalin (Lyrica) treatment, their frequency of partial seizures was roughly cut in half, with a 51% reduction. PREGABALIN (LYRICA) SIDE EFFECTS The most common side effects in Lyrica's trials were dizziness, sleepiness (somnolence), dry mouth, peripheral edema, blurred vision, weight gain, and difficulty with concentration/attention. PREGABALIN (LYRICA) PHARMACOKINETICS SUMMARY Plasma and/or tissue concentrations were determined in mice, rats, and monkeys following Pregabalin (Lyrica) administration. Pregabalin (Lyrica) was found to be rapidly absorbed in animals and mainly excreted in urine as unchanged. Pregabalin (Lyrica) renal clearance and volume of distribution in humans are well predicted by pre-clinical species. A minor metabolite in mouse and rat urine was identified as the N-methyl metabolite. In dogs, approximately 45% of the pregabalin (Lyrica) dose was excreted in urine as N-methyl metabolite. No significant inhibition of human CYP1A2, 2A6, 2C9, 2C19, 2D6, 2E1, or 3A4 was observed in vitro at Pregabalin (Lyrica) concentrations up to 1000 mM, suggesting low probability for Pregabalin (Lyrica) to elicit drug-drug interactions through inhibition of CYP450 isozymes. Pregabalin (Lyrica) exhibited potent activities in rats in the maximum electroshock seizer test for epilepsy, in chemical allodynia models for neuropathic pain, and in Vogel conflict test for anxiety. The estimated EC50 values ranged from 1.9 ?3.7 mg/mL in the rat models, which are consistent with the steady state average Pregabalin (Lyrica) concentrations (1.6 - 5.6 mg/mL) in humans at efficacious doses of 150 - 600 mg/day. [2] POSSIBLE ADVERSE EFFECTS AFTER WITHDRAWAL FROM LYRICA (PREGABALIN} A case of brain swelling, or cerebral edema, after abrupt withdrawal from pregabalin (Lyrica) was reported. [1] In a study testing the drug for the severe pain of shingles, or postherpetic neuralgia, a 80 year old female patient suffered nausea, headache and loss of balance after abruptly discontinuing the drug. A week later, she started to experience hallucinations and delirium. Researcher found swelling in the same part of the brain that is affected in some epileptic patients who also suddenly stop their medications. However, a single case can not constitute proof of these adverse effects linked to the abrupt withdrawal of the Lyrica (pregabalin). It might be just coincidental. Anyway, when a patient stops an medication, he or she should stop it under physician guidance. [1] DOSING Lyrica can be given to patients two or three times a day. It's classified as a controlled substance. REFERENCES [1] NICHOLAS BAKALAR Case Raises New Concern Over Withdrawal of Drugs The New York Time.Com July 19, 2005 [2] R. Feng et al, Pregabalin: Pharmacokinetics, Pharmacodynamics and Interspecies Scaling FDA Abstract Review Board Number: A-17 |