INDICATIONS AND USAGE Essential hypertension, alone or as an adjunct.

WARNINGS In a few patients hydrALAZINE may produce a clinical picture simulating systemic lupus erythematosus including glomerulonephritis.

In such patients hydrALAZINE should be discontinued unless the benefit-to-risk determination requires continued antihypertensive therapy with this drug.

Symptoms and signs usually regress when the drug is discontinued but residua have been detected many years later.

Long-term treatment with steroids may be necessary.

(See PRECAUTIONS, Laboratory Tests .)

ADVERSE REACTIONS Adverse reactions with hydrALAZINE are usually reversible when dosage is reduced.

However, in some cases it may be necessary to discontinue the drug.

The following adverse reactions have been observed, but there has not been enough systematic collection of data to support an estimate of their frequency.

Common headache, anorexia, nausea, vomiting, diarrhea, palpitations, tachycardia, angina pectoris.

Less Frequent Digestive constipation, paralytic ileus.

Cardiovascular hypotension, paradoxical pressor response, edema.

Respiratory dyspnea.

Neurologic peripheral neuritis, evidenced by paresthesia, numbness, and tingling; dizziness; tremors; muscle cramps; psychotic reactions characterized by depression, disorientation, or anxiety.

Genitourinary difficulty in urination.

Hematologic blood dyscrasias, consisting of reduction in hemoglobin and red cell count, leukopenia, agranulocytosis, purpura; lymphadenopathy; splenomegaly.

Hypersensitive Reactions rash, urticaria, pruritus, fever, chills, arthralgia, eosinophilia, and rarely, hepatitis.

Other nasal congestion, flushing, lacrimation, conjunctivitis.