Renese-R (Polythiazide / Reserpine) - Drug Interactions, Contraindications, Overdosage, etc

DRUG INTERACTIONS

Polythiazide

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

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).

OVERDOSAGE

One case of RENESE-R overdosage is reported after ingestion of an unknown number of tablets. Electrolyte replacement therapy was successful in treating the symptoms.

Polythiazide

An overdose of Renese may cause electrolyte imbalance, manifested by fatigue, muscle weakness, cramps, gastrointestinal disturbances, lethargy, tachycardia, and/or other arrhythmias, and hypotension.

Should overdosage with Renese occur, electrolyte balance and adequate hydration should be maintained. Gastric lavage is recommended followed by supportive treatment. Where necessary, this may include intravenous dextrose and saline with potassium and other electrolyte therapy, administered with caution as indicated by laboratory testing at appropriate intervals.

Reserpine

Signs of overdosage include CNS depression ranging from drowsiness to coma, bradycardia and hypotension, respiratory depression, hypothermia, diarrhea, vomiting, mental depression, skin flushing, miosis, and extrapyramidal signs such as stiffness and tremors. Emesis or gastric lavage to remove unabsorbed drug is of benefit in conscious patients, even if several hours have elapsed since ingestion. Treatment is symptomatic and supportive.

Parasympathomimetic side effects usually can be controlled with small doses of atropine or other anticholinergics. Evidence of motor dysfunction often can be controlled by drugs useful for parkinsonism. Avoid vasopressor drugs (except in cases of extreme hypotension) and rapid intravenous infusions because of the uncertain cardiac status.

It is not known whether dialysis would be of benefit in treating cases of overdosage of RENESE-R.

CONTRAINDICATIONS

A. Related to polythiazide

1. Advanced renal or hepatic failure.
2. Hypersensitivity to this or other sulfonamide derivatives.

B. Related to reserpine

1. Demonstrated hypersensitivity.
2. Patients with a history of mental depression.
3. Demonstrated peptic ulcer or ulcerative colitis.