Medications used to treat hypertension are known to reduce the risk of complications such as stroke, congestive heart failure, renal failure and myocardial infarction that are often associated with hypertension. Despite strong evidence of the effectiveness of such medications, little is known about whether they should be continued throughout a patient's lifetime. Withdrawal of medications has far-reaching implications, including reductions in potentially serious side effects and savings to patients that may range up to $1 billion annually. Froom and colleagues reviewed available studies of the withdrawal of antihypertensive medications and surveyed 1,000 family physicians in New York state regarding the frequency of such attempts.

An extensive MEDLINE search yielded only 18 trials in which antihypertensive medications were withdrawn from patients. Despite differences in research design and patient characteristics, data from 12 trials were combined for use and judged appropriate for reporting in this study. Four of the 12 trials used placebo, and six studies were limited to patients 60 years of age and older. Successful withdrawal was achieved in 40.3 percent of 765 patients at one year; at two years, only 27.7 percent of patients were still not taking the medication. In patients 60 years of age and older, successful withdrawal was achieved in 26.2 percent for an average period of two years or more. All trials displayed decreasing success rates over time.

A number of factors predicted the success of withdrawal. The most common predictor was a lower blood pressure before treatment. Other factors included female gender, lower diastolic blood pressure during treatment, absence of family history of hypertension, ease of control of blood pressure with medication, and both longer and shorter duration of therapy. In addition, combining weight reduction and a decreased salt and alcohol intake with medication withdrawal was more successful than withdrawal of medication alone.

Of the 1,000 family physicians surveyed about attempts to withdraw antihypertensive therapy in patients, 535 responded. Among these, 79 percent reported that they sometimes stopped therapy in patients whose blood pressure was well controlled and who were free of symptoms. On average, these physicians had discontinued antihypertensive medications in 5.6 patients in the preceding six months. These results suggest that a substantial percentage of family physicians in New York state attempt to withdraw medications in some of their patients.

The authors support previously reported recommendations that withdrawal may be attempted in patients taking a single antihypertensive agent who are normotensive for six to 12 months, and those taking a single agent for mildly elevated blood pressure if they have lost weight and/or begun to exercise during therapy. Once medication is withdrawn, patients should be monitored every three to six months for the rest of their lives and should be encouraged to maintain proper weight, to exercise and to avoid excess intake of sodium and alcohol. Patients taking multiple blood pressure medications may be candidates for withdrawal of all but one medication after achieving normotensive status for six to 12 months. Counseling for risk factor reduction should be provided.