acyclovir and its congeners can rarely result in psychosis , mania and neurotoxicity in elderly , immunocompromised individuals.[14 ] however , there are no reports of acyclovir - associated hypomania in psychiatric population .
mrs a is a 55-yr - old lady with bipolar affective disorder for the last 33 years with hypothyroidism since 2 years .
her last episode was 10 months back , when she was diagnosed as mania with psychotic symptoms and subsequently was on treatment with tab .
she presented to us with a 3-day history of irritability , increased talkativeness and decreased need for sleep .
five days before the onset of these symptoms , patient had vesicular lesions over the body which was diagnosed as chicken pox by dermatologist ( she did not have past history of chicken pox ) .
the hypomanic symptoms were reported to have started after 24 hrs of starting acyclovir . on mental status examination , she was distractible , had irritable mood , emotional liability , increased psychomotor activity and decreased attention span .
she did not have any psychotic symptoms . on young mania rating scale ( ymrs )
her thyroid profile showed mild elevation of tsh-9.28 mciu / ml ( normal : 0.28 - 6.82 mciu / ml ) with normal t3 , t4 levels .
she was diagnosed as having bipolar affective disorder , current episode hypomania ( icd-10 ) .
she showed improvement in symptoms after 1 week ( ymrs score 7 ) and was discharged from hospital .
index patient had an episode of hypomania within a week of developing chicken pox and 24 hours after starting acyclovir .
previous reports have documented psychiatric manifestations due to acyclovir and its congeners in elderly individuals with immunocompromised state or physical illness.[25 ] although an earlier report reported resolution of symptoms after stopping acyclovir , we started her on olanzapine in view of her past history of severe manic episodes .
on naranjo adverse drug reaction probability scale she had a score of 4 indicating a possible association .
we did not find any previous report of varicella zoster infection resulting in mania or hypomania , thus making it unlikely to be associated with the index episode .
however , index episode being secondary to stress associated with chicken pox though , less likely , is still possible . in conclusion
, our report suggests that acyclovir is a risk factor for mood episode in vulnerable individual and one need to be cautious while using antiviral agents in patients with psychiatric disorders .
 acyclovir , a commonly used antiviral drug can rarely result in neuropsychiatric complications especially in elderly . 
 we for the first time report acyclovir associated hypomania in an elderly woman . 
 our report suggests that acyclovir is a risk factor for mood episode in vulnerable individual and one need to be cautious while using antiviral agents in patients with psychiatric disorders . 
INTRODUCTION
CASE REPORT
DISCUSSION