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DRUG & THERAPEUTICS LETTER
A Quarterly Bulletin from
Drug Information Unit (DIU)
Department of Clinical Pharmacology
Tribhuvan University Teaching Hospital
Institute of Medicine, Maharajgunj, Kathmandu.
January – March 2006
Contents
Medication Overuse Headache
Prescribing by Denatal Surgeon
for HIV Infection
Drug Committee, TUTH
Eye problem reported with
Sildenafil (Viagra)
caused directly by medication, suchas nitrates and related compounds.
Medication Overuse Headache
Although medication overuseheadache is associated with tolerance misuse pain medication, and that aminimum 1% of the general Patients taking analgesia for otherreasons (for example, arthritis) are Disorders: ICHD-II) medicationoveruse headache is subdivided sumatriptan) produce medication Medication overuse headache is notoveruse headache more quickly, and associated with focal or lateralisingat a lower frequency of use than neurological symptoms. However,either simple patients with a history of migraine headache may experience an aurabefore the headache emerges.
from apparently infrequent (three medication overuse headache istimes weekly) or relatively short- withdrawal term treatment. Medication overuse medication, but in most cases that headache is estim ated to be patients find it very difficult to responsible for 30% of chronic daily accept that the medication they use headache, and accounts for 10-60% to treat their headaches is actually of patients attending specialist making their situation worse.
headache clinics. A high index ofsuspicion is therefore appropriate Following successful withdrawal offor any patient presenting with the overused medication, migrainefrequent headache.
prophylaxis, careful assessment ofprecipitants, counseling, a headache There are no useful diagnostic tests management plan and clear limitsfor medication overuse headache. on the use of analgesia may all beThe history is by far the most required in order to prevent relapse.
important item of information. A Studies suggest that following critical aspect of the history is the medication overuse headache will temporal course of the headache, relapse in approximately 40% of from patients. This relapse is most likely intermittent pain or headache to to occur in the first 12 months continuous, or frequent (at least following withdrawal.
every alternate day) headache. Thecharacteristics of m edication The prevalence of medicationoveruse headache are not uniform. overuse headache is high and theThe headache may vary in severity, condition is usually present for a longtype and location.
such as peri-oral paraesthesia canoccur with antiretroviral drugs.
Reference:
David Williams. Medication overuse
living with HIV/AIDS are smokers.
These patients therefore have an Brief Information
increased likelihood of oral diseasessuch as periodontal disease, Prescribing by Dental Surgeon for
HIV Infection
carcinom a so thorough dentalexam ination, HIV infection is expected to rise andthese people are increasingly likely Drug Committee, TUTH
to seek care from practitioners fromdifferent increase in number and complexityof antiretroviral regimens and the - ensuring quality and cheap drugs associated with visual disturbances in the hospital. The purchase is most notably changes in perceptionbased on the list of manufacturers of colour hue or brightness.
approved by various depart- WHO Drug information (Vol. 19, Eye problem reported with post marketing reports of sudden
Sildenafil (Viagra)
visual loss, attributed to NAION ( nonarteritic ischemic optic neuropathy),a condition where blood flow is Sildenafil is used widely for blocked to the optic nerve.
treatment of erectile dysfunction. Itacts phospho- FDA advises patients to stop taking diesterase 5 (PDE5) enzym e this medicine and contact a doctor responsible for metabolism of cGMP or healthcare provider immediately that causes relaxation of smooth if they experience sudden or muscle of corpus cavernosum and decreased vision loss. Further, they should be asked about history ofsevere loss of vision in the past The adverse effects of sildenafil is before instituting the therapy.
largely predictable on the basis ofit’s effect on PDE5. Headache, So far, it has not been determinedflushing and rhinitis m ay be whether this oral medicine forobserved with its use.
erectile dysfunction was the causeof the loss of eye-sight or whether Sildenafil also is a weak inhibitor of the problem is related to otherPDE6, the iso-enzyme responsible factors such as high blood pressurefor signal or diabetes or to a combination of transduction and sildenafil has been these problems.
"Drug and Therapeutics Letter" is also available now in the following websites:http://www.teachinghospital.org.np/diu.html, Chief Editor : Prof. Kumud Kumar Kafle
Editors : Dr. Sanu Maiya Shakya and Dr. Sangha Ratna Bajracharya
Department of Clinical Pharmacology, Drug Information Unit, Room Number: 1-85
Doctors' Room Block, TU Teaching Hospital, P.O. Box : 3578, Maharajgunj, Kathmandu.
Phone No. : 4412404 Extn 1093, E-mail : diu@healthnet.org.np

Source: http://www.teachinghospital.org.np/vol13no1.pdf