It is important that your doctor check your progress at regular visits to make sure that this medicine is working properly.
Dizziness, lightheadedness, or fainting may occur, especially when you get up from a lying or sitting position. This may be more likely to occur in the morning. Getting up slowly may help. If you feel dizzy, sit or lie down. When you get up from lying down, sit on the edge of the bed with your feet dangling for 1 or 2 minutes. Then stand up slowly. If the problem continues or gets worse, check with your doctor.
The dizziness, lightheadedness, or fainting is also more likely to occur if you drink alcohol, stand for long periods of time, exercise, or if the weather is hot. While you are taking guanadrel, be careful to limit the amount of alcohol you drink. Also, use extra care during exercise or hot weather or if you must stand for long periods of time.
Do not take other medicines unless they have been discussed with your doctor. This especially includes over-the-counter (nonprescription) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems, since they may tend to increase your blood pressure.
Before having any kind of surgery (including dental surgery) or emergency treatment, tell the medical doctor or dentist in charge that you are taking guanadrel.
Tell your doctor if you get a fever since that may change the amount of medicine you have to take.