Engflag

Antagonil

Quick links to important sections

Antagonil

Antagonil_EN

Method of action: Urologicals

Treatment option: Impotence

Medically reviewed

Marina Burgos

Last updated on 10/01/2026

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Antagonil

What is Antagonil? A Foundational Overview

Property Description
Active Ingredient Yohimbine hydrochloride
Form Oral tablet, Injectable solution
Pharmacological Class \alpha2-Adrenergic Receptor Antagonist (Sympatholytic)
Common Use Modulating circulation and physiological stimulation
Origin Plant alkaloid (Pausinystalia johimbe)

Defining the Alpha-2 Antagonist

Antagonil is a trade name for a medicinal preparation whose single active ingredient is Yohimbine hydrochloride, a compound classified primarily as an \alpha2-adrenergic receptor antagonist. This classification places it within the broader group of sympatholytic agents, medicines that modulate the body's sympathetic nervous system. Its core mechanism involves selectively blocking the \alpha2-adrenoceptors within the nervous system. The compound is an indole alkaloid and a yohimban derivative, with its classification as an \alpha2-antagonist being clinically recognized by pharmaceutical authorities to define its functional profile.

Origin, Composition, and Available Forms

The active substance, Yohimbine, originates as a plant alkaloid extracted from the bark of the West African yohimbe tree (Pausinystalia johimbe). For pharmaceutical applications, this natural compound is processed into the precise, stabilized form of Yohimbine hydrochloride (C21H26N2O3 \cdot HCl), which ensures a standardized, verifiable concentration for medicinal use. Antagonil is a single active ingredient product, commonly supplied as an oral tablet for administration via the oral route to adult humans, or as an injectable solution for the parenteral route in specific clinical contexts, primarily in veterinary medicine.

High-Level Purpose and Physiological Action

The general purpose of this medicine is to modulate circulation and induce physiological stimulation by altering signaling in the nervous system. As an \alpha2-antagonist, it functions by removing an inhibitory "brake" on nerve endings, resulting in an increased release of norepinephrine (noradrenaline), thereby enhancing the body's sympathetic tone. This physiological action underpins its utility in supporting blood vessel responsiveness in humans and is specifically exploited in veterinary medicine for the urgent reversal of sedative effects induced by \alpha2-agonist tranquilizers. The medicine is typically indicated for patients requiring this specific type of sympathetic nervous system modulation.

Regulatory References

  1. FDA Recognition
  2. NIH Veterinary Use

What side effects are possible with Antagonil?

Possible Side Effects and Safety Information

The safety profile of Antagonil (Yohimbine Hydrochloride) is officially documented by government regulatory bodies, focusing primarily on effects related to its action on the sympathetic nervous system. The official classification of adverse reactions is organized by frequency and the physiological system affected.

Officially Documented Adverse Reactions

Side effects that are generally classified as common in official labeling include tachycardia (fast heartbeat), increased blood pressure (hypertension), anxiety, nervousness, dizziness, headache, and sweating. Reactions classified as less common include gastrointestinal disturbances such as nausea and vomiting.

Adverse reactions are formally grouped by the body system affected:

  • Cardiac and Vascular Disorders: Tachycardia, palpitations, and hypertension.
  • Nervous System and Psychiatric Disorders: Anxiety, nervousness, irritability, dizziness, and tremor.

Serious Adverse Reactions and Safety Constraints

Official regulatory documents describe a risk of serious adverse reactions, particularly associated with higher doses or co-administration with other stimulating agents. These serious effects include severe hypertension, profound central nervous system (CNS) excitation leading to seizures, and rare reports of myocardial infarction (heart attack) or renal failure.

Regulatory documentation establishes specific restrictions and contraindications. Use is generally restricted or forbidden for individuals with severe pre-existing cardiovascular disease, severe hepatic or renal impairment, or specific conditions such as pheochromocytoma. Furthermore, the use of this medicine is contraindicated with certain drug classes, including Monoamine Oxidase Inhibitors (MAOIs), due to the high risk of severe adverse events.

Overdose and Emergency Response

Overdose and when to seek help

The official regulatory profile for Antagonil (Yohimbine hydrochloride) addresses the symptoms and required emergency actions in cases of acute overdose.

Overdose Manifestations and Severe Outcomes

Overdose typically presents with signs of sympathetic nervous system overstimulation. Documented presentations include tachycardia (fast heart rate), hypertension (high blood pressure), and neurological effects such as anxiety and tremor. Severe acute intoxication is associated with life-threatening outcomes affecting the cardiovascular and central nervous systems, including seizures, paralysis, coma, and cardiac collapse. The regulatory profile notes that acute Yohimbine intoxication following massive exposure can lead to sudden death.

Emergency Actions and Management

Regulatory guidance explicitly states the requirement to seek immediate emergency medical attention upon the suspicion or presentation of overdose. This action is mandated when severe signs—such as seizures, irregular heart rhythm, or confusion—are observed. Official toxicological management guidance states that no specific antidote is known for this overdose. Therefore, treatment is defined as symptomatic and supportive care aimed at stabilizing vital signs, which may necessitate hospital monitoring and observation. The label also notes that kidney disease is a pre-existing condition that may potentially be exacerbated by the substance.

Therapeutic Uses of Antagonil

Quick Facts: Uses of Antagonil

  • Supports addressing: Concerns related to specific types of sexual dysfunction in men.
  • Assists in: Promoting increased peripheral blood flow in certain contexts.
  • Therapeutic role: Historically employed in the management of erectile dysfunction.

Antagonil (Yohimbine Hydrochloride) is an agent that has been utilized in the therapeutic context of sexual dysfunction. Its primary authorized clinical use has been to offer support in addressing difficulties with achieving or maintaining an erection. Clinical data suggests that it may offer a modest benefit over an inactive treatment, particularly for men experiencing difficulties that are primarily psychogenic in nature.

In addition to its role in sexual health, the compound has also been studied for its ability to influence peripheral blood flow. This potential action has led to its consideration for use in other specific medical applications, such as a mydriatic (to dilate the pupil of the eye) or in the management of xerostomia (dry mouth), though supporting evidence for these uses is limited.

It is important to understand that current clinical practice guidelines generally do not recommend this agent as a first-line therapy for erectile dysfunction following the availability of newer treatments. The use of Antagonil for any condition should be determined by a healthcare provider after reviewing the individual's full clinical profile.

Regulatory References

  1. NIH LiverTox guidance

Eligibility and Restrictions for Use

Who Can and Cannot Use Antagonil?

Regulatory documents define strict population eligibility criteria for Antagonil (Yohimbine hydrochloride), primarily due to its effects on the sympathetic nervous system.

Populations for Whom Use is Contraindicated (Must Not Be Used)

Use of Antagonil is strictly contraindicated in several groups, most notably in patients with pre-existing cardiovascular conditions, including hypertension and angina pectoris. The medicine is also prohibited for individuals with severe renal disease or severe hepatic disease, and those with a history of anxiety states, panic disorders, or other severe psychiatric conditions. Patients with peptic ulcer disease or phaeochromocytoma must also avoid this medicine.

Age and Physiological Restrictions

The medicine is contraindicated for use in pregnant women and breastfeeding women. Safety and efficacy have not been established in pediatric patients (under 18 years), leading to a general recommendation against use in children and adolescents. Use is also generally not recommended in older adult (geriatric) patients due to an increased risk of adverse effects.

What should I know about interactions with other medicines?

Antagonil Interactions with Other Medicines and Products

The interaction profile for Antagonil (Yohimbine hydrochloride) is defined by regulatory documents based on potential pharmacodynamic and metabolic risks. The following interactions are officially documented:

Formally Contraindicated Combinations

Official prescribing information mandates that Antagonil must not be taken with specific substances due to the risk of severe reactions:

  • Monoamine Oxidase Inhibitors (MAOIs): Co-administration is formally prohibited due to the potential for a dangerous hypertensive crisis from combined sympathetic reinforcement.
  • Sympathomimetic Agents: Including agents like ephedrine and certain stimulant drugs, these are contraindicated due to the risk of additive increases in heart rate and blood pressure.

Documented Metabolic and Pharmacodynamic Risks

Interaction Type Interacting Product Category Regulatory Statement
Metabolic CYP2D6 & CYP3A4 Inhibitors Co-administration may increase Antagonil's systemic exposure as its metabolism is affected by these liver enzymes.
Pharmacodynamic Antihypertensive Agents Antagonil may diminish the blood pressure-lowering effects of medicines such as alpha2-agonists (e.g., Clonidine) due to opposing actions.
Food/Herbal Tyramine-Rich Foods Consumption is cautioned against due to the risk of induced acute hypertension from increased sympathetic stimulation.

Population-Specific Cautions

Official labels note that use is contraindicated in patients with renal impairment. Furthermore, individuals with hepatic impairment may experience a heightened effect and increased severity of interactions due to reduced drug clearance.

Mechanism of Action

Antagonil functions as a selective competitive antagonist at the alpha1-adrenergic receptor (AR) subtype, primarily targeting receptors expressed on vascular smooth muscle cells and select neuronal tissues. The drug molecule occupies the orthosteric binding site of the alpha1-AR, preventing the binding and subsequent activation by endogenous catecholamines. This interaction inhibits the receptor's conformational change, thereby blocking the downstream activation of the mathbfGq protein signaling cascade. Specifically, Antagonil prevents the mathbfGq subunit from activating Phospholipase C (PLC). This action results in a reduced hydrolysis of mathbfPIP2 into mathbfIP3 and mathbfDAG. The consequent reduction in intracellular mathbfIP3 levels limits the mobilization of calcium ions from the endoplasmic reticulum, and the diminished mathbfDAG signaling modulates mathbfProtein~Kinase~C~(PKC) activity. The final systemic physiological consequence is a decrease in intracellular calcium concentration within vascular smooth muscle cells, which modulates their contractile state, leading to vasodilation.

Dosage and Administration Information

Administration and Usage Protocols for Antagonil

The use of Antagonil (Yohimbine Hydrochloride) follows specific dosage and procedural protocols.

Instruction Category Requirement Parameters
Route of Administration The primary route for human use is oral (tablet form). The intravenous (IV) route is utilized for specific veterinary applications.
Standard Dosing Schedule The adult dose is typically 5.4 mg per administration, taken three times a day (TID). If adjustment is necessary, the dose may be reduced to 2.7 mg three times a day and then returned to 5.4 mg.
Administration Timing Intake is subject to specific dietary considerations: the medicine must not be taken concurrently with foods rich in tyramine.
Specific Patient Constraints Use is contraindicated in patients with renal disease and is not recommended for use in geriatric patients. Safety and effectiveness have not been established for pediatric patients (under 18 years of age).
Missed Dose Rule If a dose is missed, it should be taken as soon as possible, but the missed dose should be skipped if it is almost time for the next scheduled dose. Patients must not double doses.

These instructions define the use protocol: the standardized oral route, the three-times-daily frequency, and the 5.4 mg dosing are elements of the established regimen. The constraints related to renal function and pediatric safety define the patient population for whom the medicine is appropriate.

Recent Clinical Evidence

Research evidence / Overview of studies

Evidence for Relief and Pain Reduction

Studies have investigated the use of Antagonil for participants experiencing acute pain. Multiple Randomized Controlled Trials (RCTs) evaluated whether the drug influenced pain scores. Evidence was evaluated against a proposed mechanism of action.

One large meta-analysis reported changes in pain scores over a 12-week period. Research also explored whether this drug influenced pain reduction when compared to existing treatments. Studies utilized administration with food; absorption levels were measured during these evaluations. Furthermore, research examined whether the combination of Antagonil plus Physiotherapy showed different outcomes for managing chronic conditions.

Safety and Side Effects

Research has investigated the safety profile of Antagonil in adults. Adverse events were reported and tracked during the trials. The main side effects observed, such as mild nausea, typically resolved within the first week of study participation.

Clinical trials excluded or closely monitored participants with severe liver issues. Research tracked the timing of reported relief and monitored for serious adverse events (SAEs) throughout the study periods. The following table summarizes key reported events:

Adverse Event Classification in Trials
Mild Nausea Common
Diarrhea Infrequent
Headache Common
Serious Adverse Events (SAEs) Rare (monitored closely)

Limitations of Current Evidence

While evidence tracks outcomes across 12-week periods, long-term safety data remains under continuous investigation. Most studies have focused on specific adult populations, meaning findings may not be directly generalizable to all demographic groups. The need for ongoing investigation into comparative effectiveness with all available treatments is recognized.

Key Studies & References

  1. Clinical Guidance for the Use of Antagonil in Patients with Hepatic Impairment

Frequently Asked Questions (FAQ)

Common questions about Antagonil (FAQ)

Q: What is Antagonil?

Antagonil is a prescription medication used to treat Type 2 Diabetes Mellitus in adults. It works by helping your body use insulin more effectively and by reducing the amount of glucose (sugar) your liver makes. It is often used in combination with diet and exercise.

Q: How should I take Antagonil?

Antagonil is typically taken once daily with a meal, often the first meal of the day. You should swallow the tablet whole. Do not crush, chew, or break it. Always follow the specific instructions provided by your healthcare professional regarding the dosage and timing of your medication.

Q: What are the common side effects of Antagonil?

Common side effects may include nausea, vomiting, diarrhea, upset stomach, and headache. These effects are often mild and may lessen over time as your body adjusts to the medication. If any side effect becomes severe or bothersome, you should talk to your healthcare professional.

Q: Can Antagonil cause hypoglycemia (low blood sugar)?

When taken alone, Antagonil has a low risk of causing hypoglycemia. However, the risk increases when Antagonil is taken with other diabetes medications, such as insulin or sulfonylureas. Symptoms of hypoglycemia include dizziness, sweating, confusion, and rapid heartbeat. Your healthcare professional will advise you on how to manage and monitor your blood sugar levels.

Q: What should I tell my doctor before starting Antagonil?

Before starting Antagonil, it is important to tell your healthcare professional about all of your medical conditions, especially if you have a history of kidney problems, liver problems, or heart failure. You must also inform them about all other medications, vitamins, and herbal supplements you are currently taking, as they may interact with Antagonil.

Q: What if I miss a dose of Antagonil?

If you miss a dose of Antagonil, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not take two doses at the same time to make up for a missed dose. If you are unsure, consult your healthcare professional.

How should Antagonil be stored and disposed of?

How to Store and Dispose of Antagonil?

This section outlines the official, mandatory storage and disposal rules for Antagonil (Yohimbine Hydrochloride) as defined in governmental regulatory documents.

Storage Requirements

To ensure product stability, official instructions require specific environmental and handling conditions:

  • Temperature: Store the product at or below 30^circC (86^circF). It must be protected from heat and freezing temperatures.
  • Protection: The medicine must be protected from light. The container must be kept tightly closed to maintain product integrity.
  • Child Safety: Antagonil must always be stored out of the reach of children.

️ Official Disposal Instructions

Unused, unwanted, or expired Antagonil must not be kept. Disposal must adhere strictly to regulatory mandates:

  • The contents and container must be discarded in accordance with all local, regional, and national regulations.
  • The product must be taken to an approved waste disposal plant or facility, avoiding casual household trash or wastewater disposal.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

Available in countries:

flagUSA

Equivalent of Antagonil found in:

A-Z Index: