Source: Medicines and Medical Devices Safety Authority (NZ) Revision Year: 2022 Publisher: AFT Pharmaceuticals Limited, PO Box 33-203, Takapuna, Auckland 0740, Phone: 0800 423 823
ADHD was previously known as attention-deficit disorder or minimal brain dysfunction. Other terms used to describe this behavioural syndrome include: hyperkinetic disorder, minimal brain damage, minimal cerebral dysfunction, minor cerebral dysfunction and psycho-organic syndrome of children.
Rubifen is indicated as part of a comprehensive treatment program which typically includes psychological, educational and social measures and is aimed at stabilising children with a behavioural syndrome characterised by moderate to severe distractibility, short attention span, hyperactivity, emotional lability and impulsivity. The diagnosis should be made according to DSM-IV criteria or the guidelines in ICD-10. Non-localising (soft) neurological signs, learning disability and abnormal EEG may or may not be present, and a diagnosis of central nervous system dysfunction may or may not be warranted.
The specific etiology of this syndrome is unknown, and there is no single diagnostic test. Proper diagnosis requires medical and neuropsychological, educational and social investigation.
Characteristics commonly reported include: history of short attention span, distractibility, emotional lability, impulsivity, moderate to severe hyperactivity, minor neurological signs and abnormal EEG. Learning may or may not be impaired. The diagnosis must be based upon a complete history and evaluation of the child and not solely on the presence of one or more of these characteristics. Drug treatment is not indicated in all children with this syndrome. Stimulants are not indicated in children with symptoms secondary to environmental factors (child abuse in particular) and/or primary psychiatric disorder, including psychosis. Appropriate educational placement is essential, and psychosocial intervention is generally necessary. Where remedial measures alone prove insufficient, the decision to prescribe a stimulant must be based on rigorous assessment of the severity of the child’s symptoms.
Symptoms include daytime sleepiness, inappropriate sleep episodes, and sudden loss of voluntary muscle tone.
Careful dose titration is necessary at the start of treatment with methylphenidate. Dose titration should be started at the lowest possible dose.
Other strengths of this medicinal product and other methylphenidate-containing products may be available.
The maximum daily dosage of methylphenidate is 60 mg.
The dosage of Rubifen should be individualised according to the patient’s clinical needs and responses. Do not halve tablets. Dose equivalence when the tablet is divided has not been established.
In the treatment of ADHD, an attempt should be made to time administration to coincide with the periods of greatest academic, behavioural and social stress.
Rubifen should be started at a low dose, with increments at weekly intervals. Daily doses above 60 mg are not recommended.
If symptoms do not improve after dose titration over a period of one month, the drug should be discontinued.
If symptoms worsen or other adverse effects occur, the dosage should be reduced or, if necessary, the drug discontinued.
If the effect of the drug wears off too early in the evening, disturbed behaviour and/or inability to go to sleep may recur. A small evening dose of the normal tablet or an afternoon dose of the SR tablet may help to solve this problem.
Rubifen should be discontinued periodically to assessthe child’s condition. Improvement may continue when the drug is temporarily or permanently discontinued.
Drug treatment should not, and need not, be indefinite. It can usually be discontinued during or after puberty. However, ADHD may continue into adulthood and treatment with Rubifen may be beneficial to those patients after puberty.
Prior to prescribing, it is necessary to conduct a baseline evaluation of a patient’s cardiovascular status including blood pressure and heart rate. A comprehensive history should document concomitant medications, past and present co-morbid medical and psychiatric disorders or symptoms, family history of sudden cardiac/unexplained death and accurate recording of pre-treatment height and weight on a growth chart (see sections 4.3 and 4.4).
Growth, psychiatric and cardiovascular status should be continuously monitored (see also Section 4.4).
Blood pressure and pulse should be recorded on a centile chart at each adjustment of dose and then at least every 6 months;
Height, weight and appetite should be recorded at least 6 monthly with maintenance of a growth chart;
Development of de novo or worsening of pre-existing psychiatric disorders should be monitored at every adjustment of dose and then least every 6 months and at every visit.
Patients should be monitored for the risk of diversion, misuse and abuse of methylphenidate.
The safety and efficacy of long term use of methylphenidate has not been systematically evaluated in controlled trials. Methylphenidate treatment should not and need not, be indefinite. Methylphenidate treatment is usually discontinued during or after puberty. The physician who elects to use methylphenidate for extended periods (over 12 months) in children and adolescents with ADHD should periodically re-evaluate the long term usefulness of the drug for the individual patient with trial periods off medication to assess the patient’s functioning without pharmacotherapy. It is recommended that methylphenidate is de-challenged at least once yearly to assess the child’s condition (preferable during times of school holidays). Improvement may be sustained when the drug is either temporarily or permanently discontinued.
Treatment must be stopped if the symptoms do not improve after appropriate dosage adjustment over a one-month period. If paradoxical aggravation of symptoms or other serious adverse events occur, the dosage should be reduced or discontinued.
In the treatment of narcolepsy, the usual oral dose is 20 to 30 mg daily in divided doses, normally 30 to 45 minutes before meals, but the effective dose may range from 10 to 60 mg daily.
In hyperactivity disorders in children aged 6 years and over, the usual initial dose is 5 mg once or twice daily by mouth, increased if necessary by 5 to 10 mg at weekly intervals to a maximum of 60 mg daily in divided doses. Methylphenidate maybe given before breakfast and lunch. A later dose may be considered if the effect wears off in the evening causing rebound hyperactivity.
Rubifen SR Tablets have a duration of action of about 8 hours. They may therefore be used when a prolonged effect is desired exceeding the duration of action of conventional Rubifen tablets. Rubifen SR tablets must be swallowed whole and never crushed or chewed. Rubifen SR tablets should not be split or divided. They should be taken after meals, preferably after a substantial breakfast (see Section 5.2) for maximum duration of effect.
It may be necessary to use a combination of the standard immediate release and SR tablets in some patients to achieve the optimal clinical response. As the duration of action of Rubifen SR tablets is variable from patient to patient, it may not be possible to avoid administration of a Rubifen dose during the middle part of the day in all patients. The total absorption and duration of action of Rubifen SR tablets are maximised when it is taken with a meal.
The total daily dose should be similar to that required if the immediate formulation is used. In the fasted state, Rubifen SR 20 mg gives similar blood concentration to that expected following two Rubifen 10 mg immediate release tablets (with the second being taken four hours after the first).
Signs and symptoms of acute overdosage, mainly due to overstimulation of the central and sympathetic nervous systems, may include: vomiting, agitation, tremor, hyperreflexia, muscle twitching, convulsions (possibly followed by coma), euphoria, confusion, hallucinations, delirium, sweating, flushing, headache, hyperpyrexia, tachycardia, palpitation, cardiac arrhythmias, hypertension, mydriasis, dryness of mucous membranes and rhabdomyolysis.
Management consists in providing supportive measures, and symptomatic treatment of life-threatening events, e.g. hypertensive crisis, cardiac arrhythmias, convulsions. For the most current guidance for treatment of symptoms of overdose, the practitioner should consult a certified Poison Control Centre or current toxicological publication.
Supportive measures include preventing self-injury and protecting the patient from external stimuli that would exacerbate the overstimulation already present. If the overdose is oral and the patient is conscious, the stomach could be evacuated by induction of vomiting, followed by administration of activated charcoal. Airway protected gastric lavage is necessary in hyperactive or unconscious patients, or those with depressed respiration. Intensive care must be provided to maintain adequate circulation and respiratory exchange; external cooling procedures may be required to reduce hyperpyrexia.
The efficacy of peritoneal dialysis or extracorporeal haemodialysis for Rubifen overdosage has not been established. Clinical experience with acute overdosage is limited. Patients who have received doses higher than those recommended should be carefully monitored. In the event of overdose leading to clinically significant hypocalcaemia, reversal may be achieved with supplemental oral calcium and/or an infusion of calcium gluconate.
For advice on the management of overdose please contact the National Poisons Centre on 0800 POISON (0800 764766).
Rubifen (5 mg, 10 mg and 20 mg): 24 months.
Rubifen SR (20 mg): 36 month.
Store at or below 25°C and protect from moisture.
Rubifen (5 mg, 10 mg and 20 mg): Blister pack, PVC/Al, 30 tablets.
Rubifen SR (20 mg): Blister pack, PVC/PVdC AL (10 tbs/blister), 30 tablets.
Not applicable.
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