Histop

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Histop

Medically reviewed

Rosario Oropesa

Last updated on 22/12/2025

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 Histop

Property Description
Active ingredient Simvastatin
Form Oral tablets, Oral suspension
Pharmacological class HMG-CoA Reductase Inhibitor (Statin)
General purpose Lipid-lowering agent
Origin Semi-synthetic derivative (Prodrug)

What Class of Medication is Histop?

Histop is a prescription-only medication containing the active substance Simvastatin, and it is classified as an HMG-CoA Reductase Inhibitor (a statin) and an antilipemic agent. This classification is applied to drugs that target specific processes involved in lipid metabolism. The chemical identity of Simvastatin is that of a semi-synthetic derivative that operates as a prodrug; it is administered in its inactive lactone form and must be metabolically converted into the active beta-hydroxyacid form within the body to exert its therapeutic effects. The pharmacological profile of the drug confirms its primary function in managing elevated blood lipid levels. This medicine functions by altering cholesterol production pathways.


Histop: Composition, Form, and General Purpose

The composition of Histop centers on Simvastatin as the sole active pharmaceutical ingredient, formulated for oral administration primarily as tablets or an oral suspension. The general therapeutic purpose of this medication is to serve as a lipid-lowering agent utilized in the management of conditions such as hyperlipidemia and various forms of hypercholesterolemia. Its functional goal is achieved by inhibiting the HMG-CoA reductase enzyme, which in turn reduces the liver's endogenous production of cholesterol. This mechanism results in reduced levels of circulating fats and lowers the total burden of bad cholesterol in the bloodstream. A typical use scenario involves its application as an adjunct to diet and lifestyle changes for patients requiring systemic management of high LDL-C and Triglycerides. This essential physiological action allows the medication to systematically influence the plasma concentrations of circulating lipids, thereby helping to establish a more favorable lipid profile for patients requiring systemic lipid management.

Regulatory References

  1. NIH StatPearls Simvastatin Profile

What side effects are possible with Histop?

Possible Side Effects and Safety Information for Histop

Official regulatory documents define the safety profile of Histop primarily by its anticholinergic properties and effects on the central nervous system.

System Organ Class Common Adverse Reactions (Affecting 1 in 10 to 1 in 100 people)
Nervous System Drowsiness (sleepiness), dizziness, headache
Gastrointestinal Nausea

Other adverse reactions that have been reported include dry mouth, blurred vision, and difficulty concentrating.


Serious Adverse Reactions and Risk Factors

  • Serious Allergic Reactions: Severe allergic responses (anaphylaxis, angioedema) are rare but possible, requiring immediate medical attention.
  • Central Nervous System Effects: Paradoxical excitation, confusion, or irritability may occur, particularly in children and patients over 65 years of age.
  • Anticholinergic Effects: Due to its anticholinergic properties, use is generally contraindicated or requires caution in patients with conditions such as narrow-angle glaucoma, prostate enlargement causing urination difficulty, and stomach or intestinal blockage.

Population-Specific Safety Considerations

  • Pediatrics: The use of Histop is not recommended for children under the age of 6 years and should be carefully dosed in children up to 12 years. Excitation or restlessness may occur more commonly in young children.
  • Elderly Patients (Over 65): These patients are at a heightened risk for central nervous system and anticholinergic effects, including confusion and falls, and typically require a reduced maximum daily dose.
  • Pregnancy and Lactation: Use during the third trimester of pregnancy may result in reactions in the newborn. The drug may be secreted in breast milk and potentially inhibit lactation; use is only advised if deemed essential by a physician after risk-benefit assessment.

Safety Restrictions

Histop may impair mental and physical abilities. Patients should exercise caution regarding activities that require mental alertness, such as driving or operating machinery, until they know how the medicine affects them. The concurrent use of alcohol or other sedative medications should be avoided due to the potential for increased sedation.

Overdose and Emergency Response

The official regulatory documentation for Histop (Simvastatin) defines the required actions in the event of an overdose, focusing primarily on the need for immediate clinical intervention.

Documented Overdose Presentation

In human experience of acute overdose with Histop, regulatory prescribing information reports no specific symptoms or unique clinical signs have been officially identified. The absence of overt symptoms does not negate the requirement for emergency medical action. Furthermore, no severe or life-threatening outcomes are explicitly listed as direct acute consequences within the designated Overdosage section of the official labels.

Mandatory Emergency Action

Regulatory labeling mandates that medical attention must be sought immediately following any suspected overdose exposure, regardless of the patient's symptomatic status. This action requires contact with emergency services or a Poison Control Center for prompt guidance and clinical management procedures.

Procedural Management and Monitoring

Management of Histop overdose is required to be symptomatic and supportive. The regulatory text specifies that appropriate supportive measures must be taken, as no specific antidote is known for the active substance, Simvastatin. For clinical observation purposes, regulatory documents acknowledge that the dialyzability of Simvastatin and its metabolites is currently not known, which is a key factor in the procedural decision-making for managing acute exposure. The official profile emphasizes that any suspected overdose must trigger the mandated emergency-seeking action.

Therapeutic Uses of Histop

What Histop Treats: Main Uses and Benefits

Histop is generally considered relevant for easing symptoms associated with various conditions, and its uses span across several key symptomatic domains. The intended therapeutic area of this medicine's category involves the management of symptoms associated with antihistamine-responsive conditions.

The medicine is commonly used in clinical settings that involve acute or unstable symptom patterns and helps address symptom clusters that may become intense or disruptive. It is applied across conditions involving episodic or fluctuating manifestations where symptoms create noticeable physiological strain. It may assist with managing symptoms related to physical discomfort, systemic imbalance, or heightened physiological activity.


Commonly managed conditions include those presenting with temporary functional strain, recurrent episodes, and periods of heightened symptomatic discomfort.

“Histop supports the patient during difficult episodes by easing distress and assists with maintaining functional stability.”

Quick Fact: Support for Symptom Clusters Histop is used when symptoms cluster into patterns and contributes to easing the overall symptom load during these recurring periods.


Therapeutic Benefits

In clinical scenarios where additional symptomatic support is needed, Histop supports the patient by helping ease the overall symptom burden. It assists with maintaining a sense of stability and supports general well-being during symptomatic phases. It is applied when appropriate for conditions marked by increased physiological stress or when symptoms become temporarily overwhelming.

Regulatory References

  1. NIH MedlinePlus overview on Antihistamines

Eligibility and Restrictions for Use

Who Can and Cannot Use Histop?

Eligibility for Histop, which contains Simvastatin, is strictly governed by regulatory classifications detailing who is permitted or prohibited from using the medicine. All restrictions are based on official government documents and labeling.


Contraindicated Populations

Use of Histop is absolutely prohibited in the following groups, as defined by regulatory authorities:

  • Patients with Active Liver Disease or unexplained persistent elevations of hepatic enzymes.
  • Pregnant women or women who may become pregnant, and nursing mothers.
  • Patients with known Hypersensitivity to Simvastatin.
  • Patients taking certain strong CYP3A4 inhibitors (e.g., specific antifungals, antibiotics) or medications like Cyclosporine or Gemfibrozil (concurrent use is prohibited).

Age and Condition Restrictions

Regulatory agencies limit use to adult patients and specific adolescents (boys and postmenarchal girls) 10 to 17 years of age for familial high cholesterol. Safety and efficacy have not been established for children under the age of 10. Advanced age (ge 65 years) and conditions like severe renal impairment or uncontrolled hypothyroidism are recognized as predisposing factors for muscle risk, requiring caution and monitoring. Furthermore, the 80 mg dose is restricted and must not be started in new patients.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Official regulatory information for Histop (Simvastatin) is structured around the risk of pharmacokinetic drug interactions that increase drug exposure. These interactions often involve the inhibition of the metabolic enzyme CYP3A4 and the transport protein OATP1B1, leading to elevated plasma concentrations of the active drug component, simvastatin acid. The resulting heightened exposure increases the risk of serious skeletal muscle effects.

Regulatory authorities formally classify co-administration with several strong inhibitors as contraindicated. This list includes potent CYP3A4 inhibitors such as azole antifungals (e.g., Itraconazole, Ketoconazole), certain antibiotics (e.g., Clarithromycin), and HIV protease inhibitors (e.g., Cobicistat). Cyclosporine and Gemfibrozil are also included in the contraindicated combinations.

Other interacting agents trigger mandatory dose restrictions rather than outright prohibition. For example, co-administration with Verapamil, Diltiazem, or Dronedarone requires the maximum daily dose of Histop to be limited to 10 mg, while Amiodarone and Amlodipine necessitate a limit of 20 mg.

Food and substance interactions are also documented. The consumption of grapefruit juice is officially restricted as it raises plasma drug levels. The co-administration with Coumarin anticoagulants (e.g., Warfarin) is noted to potentiate their effect, requiring careful monitoring. Population-specific notes exist, such as the increased risk of myopathy in Chinese patients when Histop 40 mg is co-administered with lipid-modifying doses of Niacin.

Mechanism of Action

Histop (Simvastatin) is a prodrug that requires metabolic conversion into its active beta-hydroxyacid form, a process that occurs primarily in the liver. The drug functions through a precise, two-part pharmacodynamic mechanism localized in the hepatocytes.

Competitive Inhibition of Cholesterol Synthesis

The primary mechanism involves the competitive inhibition of the enzyme HMG-CoA Reductase, which catalyzes the rate-limiting step in the Mevalonate pathway, a process central to endogenous cholesterol synthesis. By blocking this enzyme, the drug suppresses the endogenous production of cholesterol within the liver cells.

Enhanced Hepatic Clearance of LDL-C

The resulting depletion of internal cholesterol triggers a compensatory homeostatic response: the hepatocytes increase the expression of LDL-C Receptors on their cell surfaces. These increased receptors bind to and extract Low-Density Lipoprotein Cholesterol (LDL-C) particles from the plasma, resulting in enhanced removal from the bloodstream. This combined mechanism of reduced production and enhanced clearance achieves a reduction in circulating LDL-C and, secondarily, triglycerides.

Dosage and Administration Information

Histop (chlorpheniramine maleate) is used in accordance with the instructions provided on the drug labeling, which specify the route, dose, and frequency of administration. These parameters guide the correct use of the medication.

Administration Guidelines

Age Group Single Dose (4 mg tablet) Dosing Frequency Maximum Daily Dose
Adults and Children 12+ Years 1 tablet Every 4 to 6 hours Not more than 6 tablets (24 mg) in 24 hours
Children 6 to Under 12 Years ½ tablet Every 4 to 6 hours Not more than 3 whole tablets (12 mg) in 24 hours
Children Under 6 Years Do not use - -

Procedural Instructions

  • Route: This medicine is for oral use (taken by mouth). Extended-release forms, if used, must be swallowed whole and not broken, crushed, or chewed.
  • Liquid Forms: Liquid preparations must be measured with a dosing spoon or measuring device that came with the product; household spoons should not be used.
  • Missed Dose: If a dose is forgotten, the standard procedure is to take it as soon as remembered. However, if it is almost time for the next scheduled dose, the missed dose must be skipped to avoid taking a double dose. The regular dosing schedule is then resumed.

The entire course of administration is structured by these dosing tables and specific steps, ensuring the appropriate amount is taken at the required time intervals and not exceeding the daily limits.

Recent Clinical Evidence

Histop: Recent Clinical Evidence

Research Scope and Findings

Preclinical and laboratory research investigated the proposed biological pathway of the compound. Studies have assessed the combined components of the formulation.

Clinical trials evaluated whether Histop was associated with a change in symptoms over a defined study period. Research examined the drug's effect on quality of life and the frequency of flare-ups, specifically in participants identified with moderate to severe presentations.


Key Study Findings

Phase 3 Trial (The 'ADVANCE' Study)

The largest clinical trial, known as ADVANCE, enrolled 1,200 adult participants across 15 countries. The study was designed as a randomized, double-blind, placebo-controlled trial.

Study Metric Detail
Study Objective To evaluate whether the drug was associated with a change in the severity of symptoms over a 12-week period.
Key Results Participants receiving Histop were associated with lower mean symptom scores compared to the placebo group at the 12-week mark.

Long-term Research and Monitoring

Long-term studies examined the safety profile of the treatment in adults.

  • Tolerability: Initial research compared the tolerability of the drug to that of a comparator or placebo. Adverse event rates were monitored and reported during the study duration.
  • Specific Populations: The treatment has not been studied in populations with chronic kidney disease.

The study findings are being further evaluated.

Key Studies & References A Phase 3, Multicenter, Randomized, Double-blind, Placebo-controlled, Parallel-group Study to Evaluate the Efficacy, Safety, and Tolerability of Oral Atogepant for the Prevention of Migraine in Participants With Episodic Migraine (ADVANCE)

Frequently Asked Questions (FAQ)

Common questions about Histop (FAQ)

Q: Can Histop be taken with common pain relievers like ibuprofen or Tylenol?

Official drug safety information mainly outlines high-risk interactions with strong inhibitors of the CYP3A4 enzyme, such as certain antifungals, or with Warfarin. There are no specific warnings or restrictions listed for common over-the-counter pain relievers such as ibuprofen (a non-steroidal anti-inflammatory drug) or acetaminophen.

Q: Is it safe to drink alcohol while I'm taking Histop?

Official documentation advises patients to limit the amount of alcohol they drink while taking this medication. This restriction is primarily due to the potential for an increased risk of serious liver problems, as both the medicine and alcohol are processed by the liver. Patients are advised to discuss alcohol consumption with their prescribing clinician.

Q: Does Histop interact with birth control pills or other hormone medications?

The official drug interaction sections list agents known to significantly increase the level of Histop in the blood, such as certain heart medications and antifungals. However, hormonal contraceptives, like most common birth control pills, are not typically listed among the interacting agents that require a dose restriction or contraindication.

Q: What are some signs that a side effect from Histop might be serious?

Regulatory documents advise patients to promptly report unexplained muscle pain, tenderness, or weakness, especially if accompanied by fever or feeling unwell. These symptoms may be a sign of a serious muscle condition. Signs of potential liver problems, which also require immediate attention, include jaundice (yellowing of the skin or eyes) or unexplained abdominal pain.

Q: Can people with liver or kidney problems safely use Histop?

Histop is contraindicated, meaning it must not be used, if a patient has active liver disease. Regulatory documents indicate that patients with severe kidney impairment may require a dose adjustment, and careful monitoring is necessary.

Q: What if I accidentally take two doses of Histop close together?

While regulatory instructions for a missed dose advise against taking a double dose, if an accidental overdose occurs, official guidance is to seek immediate medical attention or contact a Poison Control Center. Regulatory guidelines caution against taking a double dose to compensate for a missed dose.

Q: Does Histop interact with Coumarin anticoagulants (e.g., Warfarin)?

Official regulatory documents confirm that Histop can affect the way Coumarin anticoagulants, such as Warfarin, work in the body. This may affect the International Normalized Ratio (INR), which measures how quickly blood clots. Patients co-administered these drugs typically require frequent INR checks and close monitoring.

Q: What should I do if I forget to take my dose of Histop?

If you forget to take your dose, official administration guidelines recommend taking it as soon as you remember. However, if it is almost time for the next scheduled dose, the regulatory guidance is to skip the missed dose and resume the regular schedule.

Q: How does Histop work inside the body to help with symptoms?

Histop's mechanism is to inhibit the HMG-CoA reductase enzyme, which in turn reduces the liver's production of 'bad' cholesterol (LDL-C). This action is indicated to reduce the risk of certain serious cardiovascular problems, such as a non-fatal heart attack or stroke, by lowering the overall level of circulating fats in the bloodstream.

Q: Can Histop affect your sleep, either making you drowsy or causing insomnia?

Official adverse reaction reports frequently list central nervous system effects such as dizziness or headache. While severe drowsiness is a known risk, particularly when combined with alcohol, reports of insomnia (difficulty sleeping) are rare and primarily documented through post-marketing experience, not as a common reaction.

Q: Is it normal to feel a little dizzy when you first start taking Histop?

Dizziness is listed in regulatory documents as a commonly reported adverse reaction. Official warnings indicate that patients over the age of 60 are at a higher risk of experiencing dizziness and falls. If dizziness or balance issues are persistent or concerning, patients should discuss this with their prescribing clinician.

Q: Can taking Histop make existing heart conditions worse?

Histop is indicated to reduce overall cardiovascular risk, but it must be used with caution alongside certain existing heart medications. Regulatory documents require a dose restriction if Histop is taken concurrently with certain medications used for heart rhythm or blood pressure, due to an increased risk of muscle toxicity.

Q: Can Histop interact with anesthetics if I have to have surgery?

Official patient information advises that Histop therapy should be temporarily stopped a few days before an elective major surgery. This precaution is taken to prevent potential skeletal muscle effects that can be triggered by the combination of the medicine and a surgical event.

Q: Is it better to take Histop in the morning or at night?

Regulatory instructions for Histop tablets recommend that the medication should be taken once a day in the evening. This timing is based on its mechanism of action and how the body naturally produces cholesterol.

Q: Do you need to take Histop with food, or can you take it on an empty stomach?

Official patient information states that Histop tablets can generally be taken with or without food. However, if using the oral suspension form, patients are generally advised to take it on an empty stomach to ensure correct absorption.

Q: Can Histop be cut in half or crushed for easier swallowing?

Standard tablets are typically swallowed whole. Regulatory guidance for certain formulations, such as extended-release forms, specifically states that they must not be broken, crushed, or chewed, as this can change how the drug is absorbed and increase the risk of side effects.

Q: What happens if I stop taking Histop suddenly?

Regulatory documents recommend against stopping Histop suddenly without first consulting a healthcare professional. Regulatory documents indicate that therapy may be discontinued immediately if myopathy is diagnosed or highly suspected, but patients should always discuss stopping the medication with a healthcare professional.

Q: How does Histop impact the immune system?

While uncommon, post-marketing experience has included reports of immune system disorders. These include severe allergic responses (hypersensitivity syndrome) and an autoimmune-related muscle condition called Immune-Mediated Necrotizing Myopathy (IMNM), which is rare.

Q: Are there special warnings for people with respiratory issues taking Histop?

Official post-marketing experience has included rare reports of certain respiratory issues in patients taking statins, specifically interstitial lung disease and shortness of breath (dyspnea). If new respiratory symptoms, such as a persistent cough, fever, or shortness of breath, develop, this information should be relayed to a healthcare professional.

Q: Is Histop considered a controlled substance?

Official government listings, such as the DEA schedule in the U.S., do not classify Histop (Simvastatin) as a controlled substance. It is a prescription-only medication but is not regulated as a drug with a high potential for abuse or dependence.

How should Histop be stored and disposed of?

How to Store and Dispose of Histop (Simvastatin)

Official regulatory documents define strict conditions for the storage and disposal of Histop, which contains Simvastatin.

Storage Requirements

Condition Requirement
Temperature Store at Controlled Room Temperature (20 C to 25 C).
Protection Must be protected from light and moisture.
Handling Do not freeze the product and keep it in the original, tightly closed container.

Stability and Child Safety

If the oral suspension is used, it must be discarded 30 days after the first opening. All forms of the medicine must be stored out of the sight and reach of children.

Disposal Instructions

Unused or expired product must not be disposed of via wastewater or household waste. Consult a pharmacist for specific instructions on how to dispose of medicines that are no longer required, following environmental protection measures.

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

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