Clonidine

How it works

     * Clonidine acts on specific receptors in the brain stem called
       alpha-adrenoreceptors to reduce heart rate and blood pressure.
     * The mode of action of clonidine in ADHD is not known.
     * Clonidine belongs to the class of drugs known as centrally acting
       alpha agonists.

Upsides

     * Clonidine may be used in the treatment of high blood pressure after
       other treatments have failed. It is usually used in combination
       with other agents for high blood pressure.
     * Slow-release forms (Kapvay brand) may be used in the treatment of
       ADHD (Attention Deficit Hyperactivity Disorder) in children over
       the age of six years.
     * May also be used off-label for other conditions, such as Tourette's
       syndrome (off-label means not an FDA-approved use but experts
       consider it still has a place in therapy).
     * Available as an oral tablet, a transdermal patch, and an oral
       extended-release tablet. The incidence of side effects may be lower
       with the transdermal patch compared with oral forms of the drug but
       people using this patch should be monitored for the appearance of a
       rash.
     * Generic clonidine is available.

Downsides

   If you are between the ages of 18 and 60, take no other medication or
   have no other medical conditions, side effects you are more likely to
   experience include:
     * Dry mouth, drowsiness, headache, fatigue, dizziness on standing and
       constipation. Clonidine may lower blood pressure and increase the
       risk of falls when going from a lying or sitting position to
       standing. Drowsiness caused by clonidine may affect a person's
       ability to drive or operate machinery.
     * Other less common effects include agitation, anxiety,
       hallucinations, skin reactions, slow heart rate and increased
       sensitivity to alcohol.
     * May cause a withdrawal reaction with abrupt discontinuation
       (symptoms include anxiety, agitation, tremor and headache
       accompanied by a rapid rise in blood pressure); taper off slowly on
       a doctors advice.
     * Transdermal clonidine may be associated with an initially localized
       skin rash at the site of application; continued use may see a more
       generalized rash develop - seek immediate medical advice.
     * Clonidine may worsen or cause arrhythmias especially when used with
       other medications that affect the sympathetic nervous system (such
       as epinephrine).

   Notes: In general, seniors or children, people with certain medical
   conditions (such as liver or kidney problems, heart disease, diabetes,
   seizures) or people who take other medications are more at risk of
   developing a wider range of side effects. For a complete list of all
   side effects, [84]click here.

Bottom Line

   Clonidine can be used to lower blood pressure and treat ADHD; however
   it causes sedation and tolerance can develop to its blood pressure
   lowering effects.

Tips

     * Avoid driving or operating machinery until the effects of clonidine
       on your functioning are known.
     * Formulations of clonidine are not interchangeable; speak to your
       pharmacist.
     * Do not crush or chew slow-release forms of clonidine; swallow
       whole.
     * Food has no effect on the absorption of clonidine.
     * Do not stop taking without your doctors advice; slow withdrawal may
       be necessary.
     * Regular monitoring of blood pressure and kidney function may be
       needed.
     * Dry eyes caused by clonidine may affect contact lens wear; try
       lubricant eye drops or seek medical advice.
     * Taking most of your designated dose of clonidine at night may help
       reduce the incidence of daytime sedation and dry mouth.
     * If you miss a dose, take the next dose as scheduled; do not take
       more than the prescribed amount in a daily period.

Response and Effectiveness

     * Clonidine is rapidly absorbed and the peak effects are seen within
       one to three hours. The blood pressure lowering effect of clonidine
       happens quickly, within 30 to 60 minutes after an oral dose, and
       the maximal effect on blood pressure occurs within two to four
       hours.
     * May be used in addition to other medications for ADHD. An
       improvement in the symptoms of ADHD attributable to clondine may
       take several days to develop.

References