iPsychology

Clonidine ( Catapres ) is used to counter the insomniac effects of the stimulants, and help children get off to sleep at night. Clonidine ( Catapres ) is used to reduce Tics in Tourette Syndrome, to decrease the physical hyperactivity in ADHD, to calm aggression, or agitation as a second-line or additional medication, and to reduce obsessive behaviour in Autism

Advantages/Disadvantages:
May suppress tics
May be preferred agent to treat aggressive or hyperaroused behaviors
More effective in controlling aggressive/hyperaroused symptoms than other agents
Improves inattentive symptoms to a lesser extent than other agents
Somnolence may limit use but often resolves with time
Rebound HTN if stopped rapidly
May be contraindicated for patients with cardiac pathologies
Availability:
0.1, 0.2, 0.3 mg
Transdermal Patch 0.1, 0.2, 0.3 mg/day (Lasts 7 days)
Starting Dose:
0.025-0.05 mg qhs
Onset of Action:
1-2 weeks for maximal effect
Duration of Action:
N/A
Dosage Adjustment:
Increase to BID after 5-7 days, then to TID after another 5-7 days. Then increase by 0.025-0.05 mg/day every 5-7 days till therapeutic effect achieved. (Titrate up very slowly to minimize somnolence --- one of the most common reasons parents dislike/discontinue this medication.)
Monitor blood pressure and heart rate with each increase in dose
To discontinue, wean over one week (9). Clonidine comes in 100 microgram tablets (and also 150). It does not need any special authority and in Australia is supplied through the Pharmaceutical Benefits Scheme (PBS) which means you only pay for the script cost.

Starting the medication
As with all medications it is recommended to start slow and with a low dose. This is particularly because of the low blood pressure side effect.

To know whether it is working, the medication needs to be given for at least a month.

Standard doses
For children, medication dosages are usually recommended according to the child's weight - the number of milligrams of medication per kilo of body weight (mg/kg). For use with developmental and behavioural problems, however, this is only a very approximate guide, and the dosage should be adjusted according to the intended goal.

For clonidine, typical doses are 3 to 10 micrograms per kilogram per day. Because it doesn't last long this may be given in two to 4 daily doses. For a 40 kg child, for example, 5 micrograms per kg would be 200 (two tablets) per day. This may be given as two tablets during the day or even 4 half tablets.

Stopping the medication
It is necessary to stop clonidine slowly because otherwise blood pressure can rise. In practical terms this may be a slow reduction over two weeks.

Chemistry
What it does
Clonidine works directly on the brain. It pretends to be an adrenaline-like chemical causing reduced levels of true adrenaline-like chemicals (noradrenaline, and serotonin). This is a simple explanation - its true effects are more complex.

How long it lasts
One tablet lasts for up to 6 hours, so for that reason it may need to be given several times a day.

Side Effects
Common
The most common and concerning side effect is low blood pressure. If it is being used, this needs to be measured. Children may be at risk of fainting if they are tired, hot or anaemic.

Clonidine can cause sedation - often this is the reason it is used.

Uncommon
Less common side effects include:

Dry mouth
Confusion
Depression
Serious
The serious effects of clonidine relate to reduced blood pressure and sedation.

With Prolonged Use
The dosage may need to increase as bodies 'get used' to this medication.

Interactions with other drugs
Care must be taken if used with any other medication that can reduce blood pressure.