Pegabalin:
1.Efficacy and safety of pregabalin
for treating neuropathic pain associated with diabetic peripheral neuropathy: a
14 week, randomized, double-blind, placebo-controlled trial:
Significant reductions in
pain were observed in patients treated with pregabalin at 300 and 600 mg/day
vs. placebo (P < 0.05). Improvements in weekly pain scores were observed as
early as week 1 and were sustained throughout the study period (300 and 600
mg/day difference from placebo at study end-point, -0.63 and -0.74,
respectively). Pregabalin produced significant improvements in weekly sleep
interference scores, the short-form McGill Pain Questionnaire, the Medical
Outcomes Study-Sleep Scale, the 36-item Short-Form Health Survey scale, and the
Patient and Clinical Global Impression of Change. Patient impressions of
numbness, pain and paraesthesia were also significantly improved. Regarding
treatment responders, 29.1 and 35.6% of patients treated with 300 and 600
mg/day, respectively, reported ≥ 50% improvement in mean pain scores (vs. 21.5%
for placebo). Pregabalin was well tolerated; somnolence (26%), dizziness (24%),
peripheral oedema (13%) and weight gain (11%) were the most common adverse
events and generally were reported as mild to moderate.
The two higher doses of
pregabalin had similar responder rates of roughly 47%, whereas the placebo rate
was 18%. These doses were also tied to significant improvements in sleep and
quality of life. Improvements in pain and sleep were noted within 1 week of
treatment and persisted throughout the study. A total dose of 300 mg/day has
also been found effective in improving pain scores, sleep interference, and
other secondary outcomes.
Conclusion:Pregabalin
was effective in reducing pain and improving sleep disturbances due to pain,
and was well tolerated in Japanese patients with painful DPN.
2. Amitriptyline vs. pregabalin in
painful diabetic neuropathy: a randomized double blind clinical trial:
Good, moderate
and mild pain relief were noted in 21 (48%), 6 (13%) and 7 (15%) patients on
pregabalin and 15 (34%), 5 (11%) and 12 (27%) patients on amitriptyline,
respectively, by patient's global assessment of efficacy and safety. Patient
and physician's global assessment, McGill pain questionnaire, Likert pain scale
and Patient Global Impression of Change showed no significant difference
between the treatments, although improvement with both treatments was seen from
the first week. Of the 52 adverse events reported, 34 (65.4%) were with
amitriptyline, drowsiness being the commonest [in 19 (43%) patients].
Pregabalin caused adverse events in 18 (25%), of which drowsiness was the most
common in nine (20%) patients. The preferred pregabalin dose was 150 mg twice
daily.
Conclusion:As there are few differences between the
two treatments in efficacy, pregabalin 150 mg twice daily might be the
alternative choice as it is associated with fewer adverse effects
3.Comparative
Study of Clinical Efficacy of Amitriptyline and Pregabalin in Postherpetic
Neuralgia:
we found a clinically
significantly better response with pregabalin compared to amitriptyline
The study included 50 patients, 32 (64%) male
and 18 (36%) female, randomized to receive either amitriptyline or pregabalin
(n=25 each). Amitriptyline was administered in a dose of 25 mg once daily and
pregabalin in a dose of 75 mg twice daily. Inclusion criteria were as follows:
postherpetic neuralgia of more than 1 month duration; pain of at least moderate
severity; and patient age 40 years or older and no pregnancy. Patients with a
history of any serious diseases (renal, cardiac, hepatic or seizure) were
excluded. Total treatment period spanned 8 weeks, with patient follow up visits
at 2, 4 and 8 weeks to assess the degree of improvement in pain perception and
any adverse reaction. Patients with four herpes zoster types were included in
this study, of which thoracic type predominated (54%). Other types were
cervical in 12 (24%), trigeminal in 8 (16%) and lumbosacral in 3 (6%) patients.
Prodromal symptoms before herpes zoster were reported by 66% of study patients.
Satisfactory improvements of pain perception at the end of 8 weeks (>75%)
were noticed in pregabalin group, which was statistically significant
(χ2=10.08; P<0.05).Dry mouth was the commonest complication in amitriptyline
group and dizziness in pregabalin group.
If pregabalin dose is reduced, discontinued, or substituted
with an alternative medication, this should be done gradually over a minimum
interval of 1 week.
“In the United States, the Food and Drug
Administration (FDA) has approved pregabalin for adjunctive therapy for adults
with partial onset seizures, management of postherpetic
neuralgia and neuropathic pain
associated with spinal cord injury and diabetic
peripheral neuropathy, and the treatment of fibromyalgia.[7] Pregabalin has
also been approved in the European Union”.
Adverse drug reactions associated with
the use of pregabalin include:
·
Very
common (>10% of patients): dizziness, drowsiness.
·
Common
(1–10% of patients): blurred vision, diplopia, increased appetite, euphoria,
confusion, vivid dreams, changes in libido (increase or decrease),
irritability, ataxia, attention changes, abnormal coordination, memory
impairment, tremors, dysarthria, parasthesia, vertigo, dry mouth and constipation,
vomiting and flatulence, erectile dysfunction, fatigue, peripheral edema,
drunkenness, abnormal walking, weight gain, asthenia, nasopharyngitis,
increased creatine kinase level.
·
Infrequent
(0.1–1% of patients): depression, lethargy, agitation, anorgasmia,
hallucinations, myoclonus, hypoaesthesia, hyperaesthesia, tachycardia,
excessive salivation, sweating, flushing, rash, muscle cramp, myalgia,
arthralgia, urinary incontinence, dysuria, thrombocytopenia, kidney calculus
·
Rare
(<0.1% of patients): neutropenia, first degree heart block, hypotension,
hypertension, pancreatitis, dysphagia, oliguria, rhabdomyolysis, suicidal
thoughts or behavior
Amitriptyline:
Disadvantages:
·
risk
of fatality in overdose
·
narrow
therapeutic index
·
strong
anticholingergic properties, and as a result severe anticholingergic side
effects
·
sedation
and mental or motor impairment
·
can
lower the seizure threshold
·
cardiotoxicity
·
weight
gain (greater increase in weight than with nortriptyline, desipramine,
zimelidine, and imipramine) 39, 24
·
possible
decreased amount of REM sleep
Amitriptyline was not approved by US FDA for this use.
References:
1.Bansal D, Bhansali A, Hota D, Chakrabarti A,
Dutta P. Amitriptyline vs. pregabalin in painful diabetic
neuropathy: a randomized double blind clinical trial. Diabet Med. 2009 Oct;26(10):1019-26. doi:
10.1111/j.1464-5491.2009.02806.x.Available from: http://www.ncbi.nlm.nih.gov/pubmed/19900234
2Arun Achar1, Partha Pratim Chakraborty2,
Samiran Bisai3, Asish Biswas4,Tapobrata Guharay5. Comparative Study of Clinical Efficacy of Amitriptyline and Pregabalin
in Postherpetic Neuralgia. Acta Dermatovenerol
Croat. 2012;20(2):89-94.
3.Satoh J, Yagihashi S, Baba M, Suzuki M,
Arakawa A, Yoshiyama T, Shoji S.Efficacy and safety of pregabalin for treating
neuropathic pain associated with diabetic peripheral neuropathy: a 14 week,
randomized, double-blind, placebo-controlled trial. Diabet Med. 2011 Jan;28(1):109-16. doi:
10.1111/j.1464-5491.2010.03152.x.Available from: http://www.ncbi.nlm.nih.gov/pubmed/21166852
4.Amitriptyline HCL (Elavil). Last updated: April 12,
2012.Available from: http://www.emedexpert.com/facts/amitriptyline-facts.shtml
