Clonidine

• Clonidine is the generic name for a drug that lowers blood pressure by altering blood chemistry, according to Drugs.com. Available only by prescription, clonidine has additionally been used to treat alcohol addiction withdrawal symptoms, although the Food and Drug Administration have not approved it for that purpose.
  Clonidine can be a dangerous drug if its use is stopped suddenly. The medication will effectively lower blood pressure, but it can cause a dangerous rebound spike in blood pressure when discontinued. Doctors will likely recommend tapering off use if a patient no longer needs the medication.
  
  

Diuretics

• Diuretics improve blood pressure by getting rid of sodium and excess fluids in the body. Often, these types of drugs are combined with other medications to achieve the desired results, according to the American Heart Association (AHA).
  Diuretics can be undesirable for diabetics, as they tend to increase blood sugar levels. Taking these types of medications are typically safe as long as a doctor is aware of the situation. Usually a change in insulin or diet will offset the changes.
  In addition, diuretics cause the body to shed too much potassium, which can lead to hypokalemia. Hypokylemia can cause fatigue, muscle cramping and abnormal heart rhythms, according to the Mayo Clinic. Replacing potassium with the proper food selections and supplements may help avoid this condition.
  
  

Beta Blockers

• Beta blockers are common hypertension medications that work by decreasing the heart rate. They are also used to treat arrhythmia and angina (chest pain), according to the AHA.
  In addition to insomnia, depression and symptoms similar to asthma, beta blockers can be dangerous to diabetics. The effects of beta blockers may hide the warning signs of low blood sugar, which include increased heart rate. Checking blood sugar levels regularly will help ensure that these types of drugs do not have serious side effects for diabetics.
  
  

Prazosin

• Prazosin is a hypertension drug known as an alpha-adrenergic blocker (alpha blocker), according to Drugs.com. These types of drugs work to decrease blood pressure by causing blood vessels to relax and allowing more blood to pass through.
  The use of Prazosin is not recommended for patients of kidney or liver disease as some complications have been reported. The more common concern over Prazosin is the dizziness and tired feeling caused by the medication. Operating a car or other equipment should be avoided while taking this medication until the patient knows how it affects him. Sitting or standing suddenly could cause fainting, and the sudden cessation of this medication may cause a rebound in high blood pressure, according to Drugs.com.
  
  

Not Taking Meds

• Note that side effects and risks are involved with any prescription medication and that these drugs are generally considered safe for use by most people. The most dangerous choice in treating hypertension may be to avoid treatment.
  Cardiovascular disease affects 80 million people in the United States and was responsible for one in every 2.8 deaths in 2005, according to the AHA.