Indications

Reserpine is an indole alkaloid extracted from Rauwolfia serpentine roots, an Indian climbing shrub. Reserpine has had FDA approval since 1955 and is one of the first agents developed to treat hypertension in clinical practice. Reserpine can be prescribed alone or combined with a vasodilator or thiazide diuretic, such as reserpine-hydrochlorothiazide, as commonly used in China for over 40 years.[1][2] Reserpine was utilized as a first-line antihypertensive therapy when initially introduced but is currently considered a second-line treatment.[3] This change in status is due to newer and more favorable antihypertensive medications with better side effects. Reserpine is no longer available in the United States. This article is available for historic purposes.

A recent clinical trial tested the effects of reserpine on refractory hypertension (RfHTN) or uncontrolled blood pressure after ≥ five antihypertensive medications from different classes. Out of 45 patients with suspected RfHTN, seven consented to participate in the clinical trial, which only six patients were able to complete.[4] For the trial, patients tapered and discontinued all sympatholytic medications before administering reserpine 0.1 mg daily for four weeks.[4] Treatment results indicate that reserpine is a potent sympatholytic agent that can lower blood pressure in patients who had unsuccessful maximal antihypertensive therapy.[4]

In the 1960s, reports indicated that depression correlated with the monoamine-depleting activity of reserpine treatment, and a neurochemical model of depression was subsequently developed.[5] Recent studies examined the association between reserpine and its depressogenic effect. A case-control, cross-sectional study was conducted from August 2018 to December 2018 to examine the correlation between low-dose reserpine use and depression in Chinese hypertensive patients at the age of 60 and over, with the mean age at 70.3 years.[6] The study utilized the Zung Self-Rating Depression Scale to develop a Chinese depression scale to measure depressive symptoms in 787 reserpine users and 787 non-reserpine users. Researchers found no statistical significance in the prevalence of mild, moderate, or severe depression between reserpine users and non-reserpine users.[6] However, it is important to note that there are limitations to this study, which include utilizing a self-rating depression scale.[6]

Reserpine has historically had other uses. Reserpine was previously utilized to treat schizophrenia and tardive dyskinesia; however, it is not currently in clinical practice for these indications.[7]

Mechanism of Action

Reserpine functions as a sympatholytic agent and antihypertensive medication by acting as an adrenergic uptake inhibitor. Reserpine binds to the storage vesicles of catecholamines, such as dopamine and norepinephrine. Specifically, reserpine irreversibly blocks VMAT-2 (vesicular monoamine transporter-2) in the adrenergic neurotransmission pathway.[8] The inhibition of catecholamine pumps results in blockage of the uptake of serotonin, norepinephrine, and dopamine into presynaptic storage vesicles. This action will then lead to their depletion by cytoplasmic monoamine oxidase from peripheral and central synapses.[3] Reserpine is lipid-soluble, so it can cross the blood-brain barrier and slow the activity of the nervous system, resulting in decreased heart rate, decreased cardiac output, decreased peripheral resistance, and lowered blood pressure.[6] The main effector regions are the cardiovascular system, central nervous system, and gastrointestinal tract.

Administration

Administration of Reserpine

 For hypertension:

• Adults – Orally: Start initially at 0.5 mg, once a day with or without food, for 1 or 2 weeks. For maintenance, reduce to 0.05 to 0.25 mg daily.
• Pediatric – Usually not recommended. If used; orally: start initially at 20 mcg daily; maximum dose at 0.25 mg daily.

For psychiatric disorders (not typically used):

• Orally: 0.5 mg once a day, but may range from 0.1 to 1 mg depending on patient response

Adverse Effects

Side effects commonly occur when patients have taken tricyclic anti-depressants are administered before starting reserpine.

Common adverse reactions:

• Nasal congestion
• Dizziness
• Drowsiness
• Depression
• Headache
• Nausea
• Vomiting
• Diarrhea
• Loss of appetite
• Dry mouth
• Arrhythmias
• Syncope
• Male impotence
• Gastrointestinal upset

 Severe adverse effects:

• Bradycardia
• Chest pain
• Hypotension
• Gastric ulceration

Contraindications

Absolute contraindications for reserpine use include the presence of:

• Active peptic ulcer
• Ulcerative colitis
• Electroconvulsive therapy
• Pregnancy
• Parkinson’s disease
• Rauwolfia alkaloid hypersensitivity
• Psychiatric depression
• Pheochromocytoma

Caution is necessary when administering reserpine to patients with a history of a peptic ulcer or gastroesophageal reflux disease (GERD) due to a possible side effect of increased gastric acid secretion.[9] At higher doses, reserpine may cause a significant incidence of mental depression, anxiety, or psychosis. The FDA categorizes reserpine as a Pregnancy class C drug.  

Relative contraindications for reserpine use include the presence of:

• Cardiac arrhythmias
• Myocardial infarction
• Renal insufficiency
• Asthma
• Elderly patients

For relative contraindications, reserpine use should be approached with caution and begin with lower doses.

Monitoring

Reserpine administered via the oral route is rapidly absorbed, reaching its peak concentration level after approximately 2 hours. Reserpine has a bioavailability of approximately 50% to 70% and an elimination half-life of 11.5 days. Administering reserpine beyond the upper dosage limit can lead to central nervous system depression, bradycardia, hypotension, lethargy, and coma. Reserpine is assigned Pregnancy Category C.

There are currently no recommended routine tests or laboratory analyses for monitoring the use of reserpine.

Toxicity

Symptoms from reported cases of reserpine poisoning include hypotension, nausea, vomiting, sedation, coma, cardiovascular collapse, and death, while the latter two are uncommon.[10]

After ingestion, toxicity symptoms will develop over the initial 4 hours and generally resolve around 18 to 24 hours.

If the patient is experiencing gastric hyperacidity, H2-histamine receptor antagonists or atropine are therapeutic options. Gastrointestinal decontamination may also be an option.

There have been no signs of clinically apparent liver injury with reserpine use.

Enhancing Healthcare Team Outcomes

The collaboration of multiple healthcare professionals is necessary to enhance patient-centered care in reserpine treatment. Every interprofessional team member needs to understand the mechanism of action of reserpine, proper dosage administration, adverse effects, and toxicity treatment to provide proper care for patients. Every team member has a role, from the physician who prescribes the drug to the pharmacist who provides the appropriate dosing. Understanding the side effects and knowing the timing of ingestion will help the healthcare team monitor possible toxicity and plan for treatment. If the nurse notices any adverse effects or signs of toxicity, he/she will have to report the findings to the physician and pharmacist to determine the best course of action to stabilize the patient. The clinician would have to consult with the pharmacist regarding the use of activated charcoal if the ingestion of reserpine was within a few hours. Once the patient stabilizes, the healthcare team must work together to determine the cause and reason for toxicity. The team should monitor the patient until all signs of toxicity have dissipated. Depending on the cause of overdose or toxicity, the healthcare team may have to consider a different medication to replace reserpine.

An integrated interprofessional team approach with collaborative decision-making, mutual respect, and communication with the patient are vital elements to enhance team performance and improve patient-centered care. [Level 5]