ebook_ADHD2019_engl.

98 Rohde, Buitelaar, Gerlach & Faraone methylphenidate, some children only require twice daily dosing whilst others still gain benefit from the addition of a third dose. Titration on to lisdexamfetamine A similar approach to that described for methylphenidate can be used with lis- dexamfetamine with a starting dose of 30 mg, increased to 50 mg and then to 70 mg once daily as required. Unlike for methylphenidate, where it is possible to calculate the appropriate dose for switching between immediate release and extended release preparations, this approach is not possible for lisdexamfetamine and dexamfetamine. Due to important differences in the pharmacokinetics and pharmacodynamics, it is not possible to calculate equivalent doses for these two medications. So, whilst a positive response to dexamfetamine does suggest that a patient is likely to respond to lisdexamfetamine, it is still necessary to indepen- dently titrate when switching between the two medications. Treatment response and adverse effects should be assessed in the same way as described above for methylphenidate. Titration on to atomoxetine Atomoxetine is prescribed for children and adolescents in a dose per weight (mg/ kg) and is therefore generally simpler to titrate than the stimulants. The standard protocol for titration on to atomoxetine is to start at a dose of 0.5 mg/kg, once daily for a week. The purpose of this first week is to reduce difficulties with initial adverse effects (especially nausea, which is very common but usually transient). The dose is then increased up to 1.2 mg/kg and continued at this dose. For older adolescents and adults, the maximum dose is capped at 100 mg/day. Whilst many of those who are going to show a response will report some positive effects after three to four weeks, a small but significant number of patients are late responders. We therefore recommend that patients are made aware of this when starting on atomoxetine and that treatment is continued for 12 weeks before a decision about response/non-response is made. When there is a partial response on 1.2 mg/kg, it is acceptable to increase the dose up to 1.8 mg/kg. (Up to a maximum of 100 mg/ day). Where there has been no response after 12 weeks, we will usually switch to an alternative treatment. Treatment response and adverse effects are again asses- sed using the same protocols that were described for methylphenidate. Titrating on to extended release guanfacine and clonidine Extended release guanfacine is designed to be taken once daily and this can be either in the morning or evening. The recommendation is to begin at a dose of 1 mg/day. Adjustments should be done in increments of no more than 1 mg/week