الكلونيدين

Clonidine maybe used orally or as patches applied to your skin, it treats high blood pressure. It acts changing concentration of certain chemicals in blood and stimulating alpha2-adrenoceptors in the brain stem that reduces transmission of a signal from brain to other areas in the body. Its action results in a decrease in peripheral resistance, renal vascular resistance, heart rate, and blood pressure.
Usually Clonidine is taken twice daily, dosage depends on individual blood pressure response of a patient. Do not use this drug if it was not prescribed to you by your physician. In case you use patches they should be applied to an area of hairless skin on the upper arm or torso, once every 7 days. When you change the patch for a new one, choose a different area of skin. 
Hypersensitivity to Clonidine or any component of the formulation. Contraindication may also include in patients with sick sinus syndrome, bradicardia, atrioventricular block (degree II and III). Cautiousness should be exercised in cases of acute myocardial infraction, Reino syndrome, endogenous depression kidney failure and others.  
Beside of signs of allergic reaction such as 
hives, 
difficulty breathing, 
swelling 
such side effects may appear: 
fast or pounding heartbeats, 
a very slow heart rate, 
swelling, 
rapid weight gain, 
confusion, 
hallucinations, 
fever, 
pale skin, 
urinating less than usual. 
If you experience them seek for immediate medical attention. 
If you missed a dose take it as soon as you remember, but if it is almost time of your next dose, just skip the forgotten dose. Do not try to compensate a missed dose by taking an extra one. 
If you suspect that you took too much of Clonidine and your blood pressure first becomes too high (severe headache, blurred vision, buzzing in your ears, anxiety, confusion, chest pain) and then followed by low blood pressure (fainting, cold feeling, slow heart rate) seek for immediate medical attention. 
Tablets and patches should be stored at room temperature 15-30 C (59-86 F) in a light- resistant container away from moisture.