comparision of efficacy and safety of oseltamivir and

7/28/2019 Comparision of Efficacy and Safety of Oseltamivir And

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nazan tuna, oguz karabay, mehmet yahyaoglu

Indian J of PharmacolAug 2011;43(4):437-40


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introduction

Influenza virus is a segmented genome, negative polarity,enveloped RNA virus.

The virus caused major pandemics in 1918(H1N1), 1957(H2N2),

1968(H3N2) & more recently in feb 2009(H1N1).

Resistance was reported to amantadine and rimantadine .

During the last outbreak, the two neuraminidase inhibitors-oseltamivir and zanamivir, were used in the treatment.

They reduce the severity, duration of the disease and prevent

deaths.


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Objectives

The study aimed to compare the efficacy and tolerability of

oseltamivir and zanamivir in the treatment of influenza


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Inclusion criteria Fever 38C &the presence ofatleast of one of the following symptoms-

sorethroat, headache, myalgia, weakness, diarrhoea, nausea, vomiting,

cough, rhinorrhea and respiratory distress.

Initiated on either oseltamivir or zanamivir within the first 48h of

disease onset.

o Not receiving other drugs of palliation.

o Age group: 17-70 yrs.

o Who were diagnosed to be suffering from influenza.

o Pt. not requiring hospitalization.

o BMI < 30

o Non-pregnant females.

o Not with chronic diseases such as bronchial asthma.


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Exclusion criteria

Pts who were tested negative negative for influenza infection onPCR testing.

Pts with chronic diseases like bronchial asthma


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Study design Retrospective, randomized study.

Open labelled.


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Methodology

Study duration- october 2009 and february 2010 duringpandemic period.

Institutional Ethics Committee- approved

Total- 136 pts records obtained.

Exclusion -56( lack of data, COPD, asthma, pneumonia)

Included 80 pts

Treatment :-

Oseltamivirtwice a day as 150mg(2x75mg) PO for 5 days Zanamivir- twice a day as 10mg(2x5mg) oral inhaler for 5 days


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MethodologyTests :-

Healing criteria- time taken for axillary temp. to be normal.

decrease in myalgia.

loss of symptoms.

lack of complications. H1N1 PCR test from nasal swab ( only 8 pts received it)

ALT, AST, CBC, CRP, Urea, Creatinine, blood glucose and

cretinine kinase levels- Day0, Day2, DAY 5 Adverse events review from registered file information.


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MethodologyStatistical evaluation:

For quantifiable variables- students t- test.

For categorical variables-X2 test.

P< 0.05 was considered statistically significant.


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Results Demographical variables Table 1

M/F ratio-1.22 ( M-44, F- 36)

Average age- 30.811.6

Detected weakness in 97.5%

myalgia in 93.8%nausea in 46.3%

diarrhoea in 23.8%

Laboratory values-Table 3

Avg baseline WBC value- 7.3K/L in oseltamivir group6.4K/L in zanamivir group

Avg urea value- 22mg/dl- in both group

On reassessing parameters on D2 & D5- no significant diff.


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Results

Efficiency values of oseltamivir & zanamivir-Table 2Fever Defervescence- 50.4hrs for O, 43.2hrs for Z

Disappearance of symptoms- 157.2hrs for O, 163.2hrs for Z

Resumption of work period- 158.4hrs for O, 145.2hrs for Z.

Adverse effects of oseltamivir & zanamivir- Table 4

Drowsiness- 37.5% in O, 27.5% in Z

Nausea- 25% in O, 15% in Z

No serious adverse effects in either group.


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Discussion

H1N1 virus is considered to be resistant to M2 inhibitors( amantadine & rimantadine) while it is sensitive to

neuraminidase inhibitors ( oseltamivir and zanamivir)

Neuraminidase inhibitors, when used within the first 48hrs of the

the disease, not only reduced infectivity but also reduced the

duration of symptoms and mortality.

In this study, no significant difference was seen between 2drugs.

Fever is more rapidly resolved with Zanamivir but the incidence of

drowsiness(37.5%) was more when compared to

Oseltamivir(22.5%)


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Discussion

Other adverse events include nausea ( O-25%, Z-15%), psychiatricproblems (O-7.5%, Z- 5%)

Respiratory distress was not found with O but was seen in Z.

Zanamivir has low bioavailability. However it is concentrated in

the oropharynx, respiratory airways and lungs.

Zanamivir should be used cautiously in pts with underlying

respiratory tract diseases.


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Conclusion Zanamivir and oseltamivir were found to have similar efficacy

in terms of symptom relief & duration to resume work.

Temp. normalization was more rapid in pts using Zanamivir.

Neither drug has serious adverse effects.

However, pts. Who used Zanamivir suffered from respiratorydisease more often.


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Merits randomized study


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Demerits

Retrospective study Not blinded

Single centric

Less sample size


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Limitations


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Is the title suitable for the study done?

Is the study hypothesis presented clearly? Is the review of literature appropriate & adequate?

Comment on the clarity & appropriateness of methodology.

Comment on the statistical analysis done.

Does the discussion extend support to the hypothesis beingtested?

Does the study add to the current knowledge?

Are limitations of the study discussed? Conflict of interest.

Overall impression of the paper.

Critique of the paper

comparision of efficacy and safety of oseltamivir and

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