Table. Drugs that can be considered for comorbidities in children with autism14-17,27.

Drug	Dose	Half-life	Best indication	Common adverse effects in young people
Sertraline	Start 0.5 mg/kg, up to 2 mg/kg. Gradual dose increases are recommended. Common dose range is 50–200 mg a day. Alternatively: • over 6 years – start at 25 mg and increase to 50 mg after 1 week then by 25 mg monthly • 6–18 years – maximum dose 200 mg a day.	27 hours	Anxiety disorders, particularly generalised anxiety disorder	In younger children agitation, labile mood. Risk of increased suicidal thinking. Withdrawal symptoms if the dose is not tapered off slowly
Fluoxetine	Start 0.5 mg/kg, up to 1 mg/kg. Average dose for 7–12 years – 20–30 mg a day. 12 years and over with eating disorders or obsessive compulsive disorder – up to 60 mg may be needed. The maximum dose for other diagnoses is 40 mg a day. Alternatively: • under 12 years – start at 5 mg and increase by 5 mg monthly to a maximum of 30 mg • 12 years and over – the maximum dose is 40 mg for major depression and 60 mg for obsessive compulsive disorder.	Active metabolite norfluoxetine 9–14 days	Depression, obsessive compulsive disorder, eating disorder symptoms including avoidant restrictive food intake disorder	Nausea, headaches, agitation, insomnia Tablets have a strong aversive flavour Risk of increased suicidal thinking
Fluvoxamine	0.5 mg/kg up to 2 mg/kg. Maximum dose generally 150 mg (divided doses once 100 mg a day is given). Alternatively: • over 8 years – start at 25 mg and increase by 25 mg monthly.	15.6 hours	Obsessive compulsive disorder, significant anxiety disorders	Agitation, restlessness, onset and offset adverse effects when starting and weaning Risk of increased suicidal thinking
Sodium valproate	5 mg/kg once a day for 2 weeks then increase if needed for mood, up to maximum of 20 mg/kg (divided doses once over 200 mg a day).	8–20 hours	Can help with mood lability and aggression particularly in those with comorbid intellectual impairment	Nausea, metallic taste, fatigue, weight gain, poor attention, Stevens-Johnson syndrome, liver toxicity Sevenfold increase in polycystic ovary syndrome Need to monitor blood concentrations, but many children with autism spectrum disorder cannot tolerate venepuncture
Risperidone	Over 5 years and below 20 kg – 0.25 mg once daily for 3 days, then increase to 0.5 mg daily. If necessary, increase by 0.25 mg every 2 weeks. Usual range 0.5–1.5 mg daily. Over 5 years and over 20 kg – 0.5 mg once daily for 3 days, then increase to 1 mg daily. If necessary, increase daily dose by 0.5 mg every 2 weeks. Usual range 1–2.5 mg daily, maximum 3 mg daily.	3–20 hours	Used in autism spectrum disorder, approved by Therapeutic Goods Administration, best for agitation, aggression, impulsivity	Weight gain, increased appetite including hoarding of food at times
Aripiprazole	6–18 years – 2.5 mg once daily for 1 week, then 5 mg once daily. If necessary, increase daily dose in 5 mg increments at intervals of at least a week, to a maximum of 15 mg once daily.	75 hours	Agitation, irritability		Less weight gain than risperidone but little sedation and can be an activating drug
Olanzapine	13–18 years if under 40 kg – 2.5 mg at night, maximum dose 5 mg. 13–18 years if over 40 kg – up to 5 mg at night, maximum dose 10 mg.	21–54 hours	Aggression and mood lability when risperidone, aripiprazole and sodium valproate have not been effective		Significant sedation, weight gain and hypersalivation
Quetiapine	Over 13 years old and under 40 kg – 25 mg at night, increase to 25 mg twice a day (or 50 mg long-acting) if tolerated, maximum dose 50 mg a day. Over 13 years old and over 40 kg – 25 mg at night and increase up to maximum dose 100 mg a day if tolerated.	7–12 hours
Atomoxetine	0.5 mg/kg a day increasing after at least 3 days. Maximum 1.2–1.4 mg/kg a day or 100 mg, whichever is lower.	17 hours	ADHD, slightly better results for inattention		Nausea, fatigue27
Methylphenidate	Under 12 years – 5 mg twice a day. Over 12 years – 10 mg twice a day. Maximum 60 mg daily.	Children: 2.5 hours Adults: 3.5 hours	ADHD		Weight loss, poor weight gain, palpitations, agitation
Dexamfetamine	6–12 years – start at 2.5 mg daily and increase at weekly intervals. Usual maximum is 20 mg in 2 divided doses. Over 12 years – 5 mg every morning, daily dose may be increased by 5 mg at weekly intervals until optimal response. Maximum 40 mg a day.	12 hours	ADHD		Weight loss, poor weight gain, palpitations, agitation
Lisdexamfetamine	6–18 years – 30 mg once each morning – if necessary, increase the daily dose by 20 mg at intervals of at least a week. Maximum 70 mg daily.
Guanfacine	Starting dose of 1 mg. Under 11 years – increase to maximum of 4 mg a day. Over 11 years – increase to maximum of 7 mg a day.	10–30 hours	ADHD		Fatigue, weight gain27

ADHD attention deficit hyperactivity disorder