The blood pressure medications which were discussed so far worked on blood vessels. Central acting agents work on brain. They prevent our brain from sending signals to our nervous system to speed up the heart rate and narrow our blood vessels.
These central acting agents, also called “Adrenergic Inhibitors”, are not much in use now (as they were used once upon a time in large measures but were later found to have strong side effects) because more effective and low side effect drugs are now available in plenty. But under certain special circumstances these central acting drugs are prescribed. These special circumstances are:
- If the patient in prone to panic attacks.
- If the patient has incidence of low blood sugar.
- If the patient is going through alcohol or drug withdrawal.
The central acting agents reduce symptoms of these conditions. One type of central acting agent. “Clonidine” is available as a skin patch. Methyldopa, another central acting agent, is often recommended to pregnant women with high blood pressure, who cannot take other blood pressure drugs because of risks to themselves and the baby.
Central Acting Agents include:
- Clonidine (Catapres, clothaltion)
- Guanabenz (Rexitence)
- Guanadrel (Hylovel)
- Guanethidine (Ismelin)
- Guanfacine (Estulic)
- Methyldopa (Alphadopa, Emdopa, Aldomet)
- Reserpine (Reserpine, Serpasil)
Side Effects and Cautions
These drugs can produce extreme fatigue, drowsiness, sedation.
They also can cause impotence, dry mouth, headaches, weight gain, impaired thinking, psychological problems like depression.
Stopping use of some central acting agents can cause the blood pressure to increase to dangerously high levels very quickly (Rebound Hypertension). If a patient wants to discontinue a central acting agent due to side effects he must gradually stop it under a doctor’s supervision.