Phenobarbitone

Phenobarbitone is oral and parenteral barbiturate with anticonvulsant and sedative-hypnotic properties. Phenobarbital is the oldest of the commonly used anticonvulsants. Phenobarbitone is also the longest-acting agent in the barbiturate group. In general, Phenobarbitone is effective in all seizure disorders except absence (petit mal). It was regularly prescribed to prevent febrile seizures, but now it is infrequently used for this due to side effects and lack of efficacy. It was first used as an anticonvulsant in 1912, and it was approved by the FDA in 1939. Anticonvulsant action of phenobarbitone is a combined result of elevating the seizure threshold and inhibiting the spread of discharges from a seizure focus. It inhibits the spread of seizure activity in the cortex, thalamus, and limbic systems, and increases the threshold for electrical stimulation of the motor cortex. There is a decrease in both pre and postsynaptic excitability.

Phenobarbitone is primarily indicated in conditions like Benign febrile convulsions of infancy, Epilepsy, Seizures, Short-term treatment of severe congestive heart failure, Status epilepticus.

Phenobarbitone is contraindicated in conditions like Porphyrias, Severe Hepatic impairment, Airway obstruction, History of sedative hypnotic addiction.

The severe or irreversible adverse effects of Phenobarbitone, which give rise to further complications include Ataxia, Confusion, Aggression, Irritability, Nystagmus, Mental disturbances. Phenobarbitone produces potentially life-threatening effects which include Agranulocytosis, Aplastic Anemia, Exfoliative dermatitis, Hepatitis. which are responsible for the discontinuation of Phenobarbitone therapy. The signs and symptoms that are produced after the acute overdosage of Phenobarbitone include Coma and death, Sedation, Stupor. The symptomatic adverse reactions produced by Phenobarbitone are more or less tolerable and if they become severe, they can be treated symptomatically, these include Skin rashes, Erythema, Morbilliform, Ataxia, Headache, Fatigue, Nystagmus, Vertigo, Stevens-Johnson syndrome, Rickets, Osteomalacia.

Phenobarbitone should be used with extreme caution in case of severe liver function, pulmonary or cardiac disease, shock or uremia. Administered with caution to patients with borderline hypoadrenal function. During prolong therapy, perform periodic lab evaluation of organ system, including renal (kidney) and hepatic (liver) system. It should be used with caution (if contains tartrazine) in patients with aspirin hypersensitivity, because may produced allergic reactions (including bronchial asthma).

Drug should not be given to Pediatrics, Pregnant Mothers, patients suffering from Liver Malfunction, Geriatrics, and Neonates. If prescribing authority justifies the benefits of the drug against the possible damages he/she should reevaluate them and consult the reference material and previous studies.

50 to 200 mg (120 (125)) 6 hourly IV,IM — 60 to 180 mg (120 (120)) 24 hourly PO — Taken at night.

3.1 mg/kg (3.1 (3.1)) 24 hourly Oral — -

3.1 mg/kg (3.1 (3.1)) 24 hourly Oral — -

Phenobarbitone is known to interact with other drugs, the details of drug interactions is as follows:DrugDetailsSeverityOnsetManagementAbacavirPhenobarbital reduces plasma concentration of abacavir.AlcoholAlfacalcidolit reduces hydroxilation of alfacalcidolAmoxapineAmoxapine antagonises antconvulsant effect of phenobarbitone; convuksive threshold lowered. Metabolism of amoxapine possibly accelerated; reduced plasma concentration. Bupropion (HCl)CalcifediolCarbamazepinePhenobarbitone may decreases Carbamazepine levels. The mechanism may be related to induction of CYP450 hepatic metabolism of Carbamazepine.CarmustineChloramphenicolPhenobarbitone causes subtherapeutic concentration of chloramphenicol.ChloramphenicolChlorpropamideClonazepamCorticotropinCyclosporin ADesogestrelDexamethasonephenobarbitone decrease plasma half life and bioavailibility of dexamethasone by 50%Dexamphetamine (Sulphate)DextropropoxypheneDiazepamBarbiturates (e.g. Phenobarbitone) potentiate the action of Diazepam and should not be given concurrentlyDigitoxinDigitoxinDi-IodohydroxyquinolineDiltiazem (HCl)Dimemorfan PhosphateDiphenhydramineDipyroneDisopyramideDoxycyclineDoxycyclineDydrogesteroneEphedrineEstazolamEstradiol (Valerate)EthinyloestradiolEthosuximideEthynodiol (Diacetate)FlunisolideFosphenytoinGallopamilGestodeneGriseofulvinGriseofulvinHydrocortisoneIndinavir (Sulphate)Influenza VaccineIopanoic AcidIotroxate (Meglumine)ItraconazoleLamotrigineLevonorgestrelLynoestrenolMegestrol (Acetate)MephenytoinPhenobarbital may interact with Mephenytoin. It can either increase or decrease the effect of Mephenytoin. MethylprednisoloneBarbiturates (e.g. Phenobarbitone ) can increase metabolism of methyl prednisoloneNicoumaloneNorgestimateNortriptyline (HCl)PemolineEffects may be additive. Use caution when pemoline is used with other CNS acting medicationsPethidine (HCl)PhenindionePhenylbutazone Phenytoin (Na)Phenytoin (Na)PioglitazonePrajmalium Bitartaratephenobarbitone increases hepatic metabolism of prajmalium bitartarate.ProgesteronePropoxyphenePyridoxinePyridoxineQuinidineRepaglinidePhenobarbitone may decrease the levels/effects of repaglinide.RitonavirSecnidazoleSertindoleSertindole has the potential of causing drowsiness, thus in combination Phenobarbitone sedation may result. Sodium ValproateStilboestrolTacrolimusTelithromycinPhenobarbitone is likely to result in subtherapeutic levels of telithromycin and loss of effect.Thiamine HCl (Vitamin B1)Barbiturates may lower thiamin levels in the body by decreasing absorption and increasing excretion or metabolism.Tiagabine (HCl)Tocainide (HCl)Verapamil (HCl)Vitamin KWarfarin (Na)Phenobarbitone may increase the metabolism, via CYP isoenzymes, of Warfarin. MajorDelayedMonitor for decreased therapeutic effects of Warfarin if Phenobarbitone is initiated/dose increased (anticoagulant dosage increases of 30% to 60% may be needed based on monitored PT), or increased effects if Phenobarbitone is discontinued/dose decreased. An increased frequency of PT monitoring should be considered for the period immediately following Phenobarbitone initiation/dosage changes. Zolpidem (Tartrate) These interactions are sometimes beneficial and sometimes may pose threats to life. Always consult your physician for the change of dose regimen or an alternative drug of choice that may strictly be required.

Inj Store Below 40°C. Do not Freeze. Tab Store in a well closed container, Below 40°C.