Dilantin Injection
Phenytoin
50mg
Pfizer Ltd.
| Pack size | 2ml |
|---|---|
| Dispensing mode | |
| Source | |
| Agent | |
| Retail Price | 170.09 NPR |
Available as:
Indications
Dilantin Injection is used for:
Epilepsy,Tonic-clonic status epilepticus
Adult Dose
Oral
Epilepsy
Adult: Initially, 3-4 mg/kg daily as single dose or in divided doses.
Alternatively, 150-300 mg daily increased gradually to 600 mg daily if necessary. Maintenance: 200-500 mg daily.
Child Dose
Oral
Control of Tonic-Clonic and Complex Partial Seizures
Initial dosage
Neonates: 5 mg/kg/day in 2 divided doses
Child: 6 months to 16 years: 5 mg/kg/day in 2-3 divided doses
Neonates (<28 days)
Initial: 5-8 mg/kg/day PO divided q8-12hr
Age-based maintenance dose
6 months-4 years: Usual range, 8-10 mg/kg/day PO divided two to three times daily
4-7 years: Usual range, 7.5-9 mg/kg/day PO divided two to three times daily
7-10 years: Usual range, 7-8 mg/kg/day IPO divided two to three times daily
10-16 years: Usual range, 6-7 mg/kg/day PO divided two to three times daily
Renal Dose
Administration
Should be taken with food. When administering to patients on nasogastric or other enteral feeds, do not administer feeds 2 hr before or after a dose. Be consistent throughout therapy in relation to feed times. Do not switch dosage forms/brands w/o prior consideration.
Contra Indications
Pregnancy.
Precautions
Cardiovascular disease, e.g. sinus bradycardia, heart blocks; DM; hepatic impairment; hypoalbuminemia; porphyria; seizures (may increase frequency of petit mal seizures); debilitated patients; elderly. Caution in IV admin in hypotension, heart failure or MI, monitor BP and ECG during therapy. IV must be given slowly (too rapid admin may cause hypotension, CNS depression, cardiac arrhythmias and impaired heart conduction). Extravasation and intra-arterial admin must be avoided. Do not discontinue abruptly (may increase seizure frequency), unless safety concerns require a more rapid withdrawal. May impair ability to drive or operate machinery.
Lactation: Excreted in breast milk; not recommended
Pregnancy-Lactation
Interactions
Effects with other sedative drugs or ethanol may be potentiated. Enhances toxic effects of paracetamol, lithium. Increased risk of osteomalacia with acetazolamide. Decreased serum levels/effects with acyclovir, antineoplastics, benzodiazeines, ciprofloxacin, CYP2C9 inducers (e.g. carbamazepine), CYP2C19 inducers (e.g. rifampin), folic acid, vigabatrin.
Increased serum concentrations with allopurinol, capecitabine, cimetidine, CYP2C9 inhibitors (e.g. fluconazole), CYP2C19 inhibitors (e.g. delavirdine), disulfiram, methylphenidate, metronidazole, omeprazole, SSRI, trazodone, trimethoprim. Increases metabolism of antiarrhythmics, anticonvulsants, antipsychotics, beta-blockers, calcium channel blockers, chloramphenicol, corticosteroids, doxycycline, oestrogens, HMG-CoA reductase inhibitors, methadone, theophylline, TCAs. Decreases levels/effects of clozapine, ciclosporin, tacrolimus, CYP2B6 substrates (e.g. bupropion, selegiline), CYP2C8 substrates (e.g. amiodarone), CYP2C9 substrates (e.g. celecoxib), CYP2C19 substrates (e.g. citalopram), CYP3A4 substrates (e.g. benzodiazepines), digoxin, itraconazole, levodopa, neuromuscular-blocking agents, thyroid hormones, topiramate.
Increases levels/effect of dopamine, ticlopidine. Valproic acid may displace phenytoin from binding sites; and affect phenytoin serum concentrations. Transiently increases the hypothrombinaemia response to warfarin initially, followed by an inhibition of the response.
Potentially Fatal: Enhances the hypotensive properties of dopamine and the cardiac depressant properties of lidocaine.
Adverse Effects
Side effects of Phenytoin :
Hypersensitivity, lack of appetite, headache, dizziness, tremor, transient nervousness, insomnia, GI disturbances (e.g. nausea, vomiting, constipation), tenderness and hyperplasia of the gums, acne, hirsutism, coarsening of the facial features, rashes, osteomalacia. Phenytoin toxicity as manifested as a syndrome of cerebellar, vestibular, ocular effects, notably nystagmus, diplopia, slurred speech, and ataxia; also with mental confusion, dyskinesias, exacerbations of seizure frequency, hyperglycaemia. Solutions for inj may cause local irritation or phlebitis. Prolonged use may produce subtle effects on mental function and cognition, especially in children.
Potentially Fatal: Toxic epidermal necrolysis, Stevens-Johnson syndrome.
Mechanism of Action
Phenytoin acts as an anticonvulsant by increasing efflux or decreasing influx of sodium ions across cell membranes in the motor cortex during generation of nerve impulses; thus stabilising neuronal membranes and decreasing seizure activity. It acts as an antiarrhythmic by extending the effective refractory period and suppressing ventricular pacemaker automaticity, shortening action potential in the heart.
Note
Dilantin 50mg Injection manufactured by Pfizer Ltd.. Its generic name is Phenytoin. Dilantin is availble in Nepal.
Farmaco Nepal drug index information on Dilantin Injection is not intended for diagnosis, medical advice or treatment; neither intended to be a substitute for the exercise of professional judgment.