Serum electrolyte determinations are especially indicated for patients with severe derangement of metabolic processes, e.g., surgery, vomiting, or parenteral fluid therapy. Electrolyte imbalance may be caused by certain diseases such as cirrhosis, or it may result from drug therapy, such as therapy with corticosteroids. Patients with cirrhosis who are continually receiving RENESE-R should be observed carefully for the development of hepatic precoma or coma. Indications of impending hepatic failure are tremor, confusion, drowsiness, and hepatic fetor.
Thiazides may precipitate kidney failure and uremia in patients with pre-existing renal pathology and impaired renal function.
Available information tends to implicate all oral dosage forms of potassium salts ingested in solid form with or without thiazides in the etiology of nonspecific, small bowel lesions consisting of ulceration with or without stenosis, causing obstruction, hemorrhage and perforation, and frequently requiring surgery. Deaths due to these complications have been reported. All oral dosage forms of potassium salts ingested in solid form should be used only when adequate dietary supplementation is not practical, and should be discontinued immediately if abdominal pain, distention, nausea, vomiting, or gastrointestinal bleeding occur.
RENESE-R does not itself contain enteric-coated potassium.
Electroshock therapy should not be given within one week of cessation of reserpine.
Reserpine may cause mental depression. Recognition of depression may be difficult because this condition may often be disguised by somatic complaints (Masked Depression). The drug should be discontinued at first signs of depression such as despondency, early morning insomnia, loss of appetite, impotence, or self-deprecation. Drug-induced depression may persist for several months after drug withdrawal and may be severe enough to result in suicide.
Since all diuretic agents may reduce serum levels of sodium, chloride, and potassium – especially with brisk diuresis or when used concurrently with steroids – patients should be observed regularly for early signs of fluid or electrolyte imbalance, and serum electrolyte studies should be performed periodically. Warning signs of possible electrolyte imbalance, irrespective of cause include fatigue, muscle cramps, gastrointestinal disturbances, lethargy, oliguria, and tachycardia. In extreme cases, hypotension, shock, and coma may develop. Frequently, serum electrolyte levels do not correlate with signs or symptoms of electrolyte imbalance. Unduly restricted salt intake as well as concurrent administration of digitalis may exaggerate metabolic effects of hypokalemia. A favorable ratio of potassium to sodium excretion lessens the possibility of hypokalemia. However, should this occur or be suspected, foods with a high potassium content (bananas, apricots, citrus fruits, prune juice, etc.) should be given. When necessary, oral potassium supplements may be administered. If other antihypertensive agents are used concurrently, lower than usual doses of RENESE-R and of the other agents should be considered.
The antihypertensive effects of the drug may be enhanced in the postsympathectomy patient.
Since reserpine may increase gastric acid secretion, it should be used cautiously in patients with a history of peptic ulcer or ulcerative colitis. Extreme caution is needed in patients with a history of mental depression, and reserpine should be discontinued at the first sign of depressive symptoms. Parkinsonism and confusion have been encountered, particularly in psychiatric patients, and constitute an indication for withdrawal of the drug. Caution should be exercised when treating patients with impairment of renal function, as lowered blood pressure may result in further decompensation and embarrassment of function.
Discontinue the drug one to two weeks prior to elective surgery since an unexpected degree of hypotension and bradycardia have been reported in patients receiving anesthetic agents concurrently with reserpine, probably due to a reduced responsiveness to norepinephrine. For emergency surgical procedures vagal blocking agents may be given parenterally to prevent or reverse hypotension and/or bradycardia. Reserpine may cause increased appetite and weight gain in some patients.
Information for Patients
Since RENESE-R may increase urination, it is advisable to take it early during the day. If stomach upset occurs, take the drug with food or milk.
Notify your physician if muscle weakness, cramps, nausea, or dizziness occur as these may indicate the loss of too much potassium from your body.
A few people who take this medicine may be more sensitive to sunlight than they are normally. Avoid too much sun or use of a sunlamp until you see how you react.
RENESE-R may cause drowsiness. Make sure you know how you react before driving, using machinery, or performing tasks that require alertness.
Notify your physician if changes in mood or sleep patterns occur. Dizziness or lightheadedness may occur when getting up from a sitting or lying position. Getting up slowly may help. Notify your physician if the problem worsens.
Determination of serum electrolytes to detect possible electrolyte imbalance should be performed at appropriate intervals.
Thiazides may add to or potentiate the action of other antihypertensive drugs. Potentiation occurs with ganglionic or peripheral adrenergic blocking drugs.
Hypokalemia may be more likely to develop during concomitant use of corticosteroids or ACTH. Diuretic-induced hypokalemia may precipitate digitalis toxicity.
Thiazide drugs may augment the paralyzing actions of tubocurarine, and may decrease the arterial responsiveness to norepinephrine. Extra precautions may be necessary in patients who may require these drugs or their derivatives, as in surgery.
Dosage adjustment of antidiabetic agents is frequently indicated during thiazide administration. Indomethacin may partially antagonize the hypotensive effect of the thiazide diuretics. Generally, do not give lithium with diuretics because they reduce lithiums renal clearance and add a high risk of lithium toxicity.
Quinidine, a weak base, may have its half-life prolonged by concomitant administration of thiazide diuretics which alkalinize the urine.
Sulfonamides may potentiate the action of the thiazide diuretics, possibly by displacement from binding sites on plasma albumin.
Orthostatic hypotension may be aggravated by the use of alcohol, barbiturates, or narcotics with thiazide diuretics.
Reserpine should be used cautiously with digitalis or quinidine as the concurrent use may enhance the appearance of arrhythmias.
Additive CNS depressant effects may occur when reserpine is administered concomitantly with other CNS depressants such as barbiturates and alcohol.
Concomitant administration of reserpine and levodopa has been reported to reduce the patient's response to levodopa. Reserpine should be avoided in patients receiving levodopa.
The effects of indirect-acting sympathomimetic amines such as ephedrine may be decreased.
Patients who are receiving monoamine oxidase inhibitors may experience excitation and hypertension when reserpine is added. The combination should be avoided.
Reserpine may add to the pharmacologic effects of beta-adrenergic blocking agents (i.e., CNS depression and cardiovascular effects).
Drug/Laboratory Test Interactions
The thiazides may alter various laboratory test results. These include all electrolytes, particularly potassium, BUN, glucose, and PBI. Thiazides may decrease serum PBI levels without signs of thyroid disturbance.
Like other thiazide diuretics, polythiazide may cause a rise in serum uric acid levels with or without overt symptoms of gout.
Chronic administration results in a decrease in urinary catecholamines and vanilmandelic acid excretion.
Interference with colorimetric assay procedures for the determination of urinary 17-hydroxycorticosteroids by the Glenn-Nelson technique and 17-ketosteroids by the Holtorff Koch modification of the Zimmerman reaction have been reported.
Although long-term studies in animals have not been conducted with RENESE-R, rodent studies have shown that reserpine is an animal tumorigen, causing an increased incidence of mammary fibroadenomas in female mice, malignant tumors of the seminal vesicles in male mice, and malignant adrenal medullary tumors in male rats. These findings arose in 2 year studies in which the drug was administered in the feed at concentrations of 5 and 10 ppm—about 100 to 300 times the usual human dose. The breast neoplasms are thought to be related to reserpine's prolactin-elevating effect.
Several other prolactin-elevating drugs have also been associated with an increased incidence of mammary neoplasia in rodents.
The extent to which these findings indicate a risk to humans is uncertain. Tissue culture experiments show that about one-third of human breast tumors are prolactin-dependent in vitro, a factor of considerable importance if the use of the drug is contemplated in a patient with previously detected breast cancer. The possibility of an increased risk of breast cancer in reserpine users has been studied extensively; however, no firm conclusion has emerged. Although a few epidemiologic studies have suggested a slightly increased risk (less than twofold in all studies except one) in women who have used reserpine, other studies of generally similar design have not confirmed this. Epidemiologic studies conducted using other drugs (neuroleptic agents) that, like reserpine, increase prolactin levels and therefore would be considered rodent mammary carcinogens, have not shown an association between chronic administration of the drug and human mammary tumorigenesis. While long-term clinical observation has not suggested such an association, the available evidence is considered too limited to be conclusive at this time. An association of reserpine intake with pheochromocytoma or tumors of the seminal vesicles has not been explored.
Pregnancy Category C
Animal reproduction studies have not been conducted with RENESE-R. There are no adequate and well controlled studies in pregnant women. It is also not known whether RENESE-R can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. RENESE-R should be given to a pregnant woman only if clearly needed.
Thiazides cross the placental barrier and appear in cord blood. When polythiazide and reserpine are used in women of childbearing age, the potential benefits of this drug combination should be weighed against the possible hazards to the fetus. The hazards include fetal or neonatal jaundice, thrombocytopenia, and possible other adverse reactions which have occurred in the adult.
Thiazides and reserpine appear in breast milk. Because of the potential for serious adverse reactions in nursing infants from RENESE-R, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Safety and effectiveness in children have not been established.