Cletus

Quick links to important sections

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 Cletus

Cletus is a synthetic prescription medicine used to control and significantly reduce the production of acid in the stomach. As a systemic drug, its primary function is to block the final mechanism responsible for acid secretion, providing sustained relief from conditions related to excess stomach acid. The formulation is primarily available in the United States, positioning it as an established, single-active ingredient option for patients requiring strong acid suppression.


Quick Facts

Property Description
Active ingredient Omeprazole
Form Delayed-release capsule (Oral)
Pharmacological class Proton Pump Inhibitor (PPI)
General purpose Sustained gastric acid suppression
Origin Synthetic Benzimidazole derivative

1. Defining Cletus: Active Ingredient and Pharmacological Class

Cletus is classified as a Proton Pump Inhibitor (PPI), containing the active ingredient Omeprazole. This substance is an antiulcer agent that is a chemically engineered substituted Benzimidazole derivative. It is a single-active ingredient product designed for oral administration. The classification of Omeprazole as a PPI is a standard classification in gastroenterology. This means that the medicine works to reduce the amount of acid the stomach makes, a therapeutic effect recognized for its potency and duration.


2. What Type of Drug Is Cletus and What Is Its General Purpose?

The general purpose of Cletus is to suppress gastric acid to mitigate discomfort and facilitate the healing of the upper digestive tract. This medicine is primarily used to control symptoms in adults requiring consistent acid reduction. By lowering the overall acidity level, the medication helps reduce the impact of acid on the stomach lining and esophagus. Cletus is commonly supplied as a delayed-release capsule, although other oral forms may exist. PPIs like Omeprazole are established as effective in reducing stomach acid levels. This means that the fundamental benefit is the long-lasting reduction of acidity, which offers therapeutic relief and supports the body’s natural repair processes.


3. How the Delivery System Ensures Efficacy

Cletus is formulated as a delayed-release capsule to protect the active ingredient, Omeprazole, from degradation by stomach acid. The capsule contains enteric-coated pellets that resist the stomach's highly acidic environment. This feature is crucial because the Omeprazole substance is rapidly degraded by acid, and the delayed release ensures the drug's full bioavailability. These pellets dissolve and release the Omeprazole once they have passed into the small intestine, where the pH is neutral. This specialized design is essential to ensure the drug's therapeutic potency, allowing the concentration of the anti-secretory substance to be absorbed.

Regulatory References

  1. Omeprazole: MedlinePlus Drug Information
  2. Omeprazole Delayed-Release Capsules Label

What side effects are possible with Cletus?

Cletus is associated with a range of officially documented adverse reactions, which regulatory agencies classify based on frequency and affected system-organ class. The most frequent adverse reactions listed in regulatory documents are generally centered in the Nervous System and Gastrointestinal System.


Frequency-Classified Adverse Reactions

The frequency classification found in regulatory labels identifies some effects as Very Common (ge 1/10 patients), including headache, diarrhea, and abnormal stools. Common reactions (ge 1/100 to < 1/10 patients) include palpitations, tachycardia, dizziness, and peripheral edema. Uncommon (ge 1/1,000 to < 1/100 patients) reactions involve serious events such as myocardial infarction (heart attack), cerebrovascular accident (stroke), and atrial fibrillation. Rare reactions (ge 1/10,000 to < 1/1,000 patients) include certain blood and lymphatic system disorders.


Serious Adverse Reactions and Safety Restrictions

Official labeling contains specific and fundamental safety constraints. The medicine is contraindicated in patients with heart failure of any severity, as documented by the FDA. Serious adverse reactions include potential for major hemorrhage and clinically significant cardiac events. Furthermore, the medicine is contraindicated for patients with known hemorrhagic tendencies or active bleeding conditions. Safety notes also exist for patients with severe hepatic or renal impairment, where caution is advised.


The overall safety profile is primarily structured by its high-frequency, non-serious effects and the absolute cardiac contraindication that severely limits its use in a specific high-risk population. These formal classifications dictate the established boundaries and acknowledged risks associated with the medicine.

Overdose and Emergency Response

Overdose and When to Seek Help

This information is based on the official overdose guidance found in government regulatory documents for the active ingredient in Cletus (Omeprazole).

Documented Overdose Presentations

Overdose manifestations recorded in human cases, including those with doses up to 2,400 mg, were generally transient (short-lived). There are no specific severe or life-threatening outcomes explicitly listed in the regulatory labeling.

Physiological System Documented Manifestations (Signs/Symptoms)
Gastrointestinal Nausea, Vomiting, Abdominal pain, Diarrhea, Flatulence
Central Nervous System Headache, Drowsiness (Somnolence), Confusion, Blurred vision
Systemic Tachycardia (Fast heartbeat), Flushing, Increased sweating, Dry mouth

Required Emergency Action

In the event of a suspected overdose, it is mandatory to seek immediate medical attention or contact a Poison Control Center for guidance. Treatment is officially described as symptomatic and supportive.

  • Antidote Status: The regulatory documents confirm there is no specific antidote available for Omeprazole overdose.
  • Management Notes: The drug is considered not readily dialyzable, meaning procedures like dialysis are not effective for removing the substance from the body. Treatment focuses entirely on managing the symptoms presented.

Therapeutic Uses of Cletus

What Cletus Treats: Main Uses and Benefits

Cletus is a medication commonly used for managing symptoms associated with Intermittent Claudication, a condition where painful muscle cramps occur primarily in the legs during physical activity. The use of this medication is relevant when supportive symptom management is appropriate for symptoms that create noticeable physiological strain and interfere with daily functioning.


Supportive Relief for Vascular-Related Discomfort

The medication is applied across domains where additional symptomatic support is needed to help ease specific symptom clusters—namely the aching, cramping, or numbness in the legs that intensifies when walking. This supportive use is relevant in clinical settings that involve acute or unstable symptom patterns. This provides support that may help patients cope more steadily with difficult episodes and can contribute to easing the overall symptom load.

“This provides support that may help patients cope more steadily with difficult episodes and can contribute to easing the overall symptom load.”


Management of Functional Strain and Walking Ability

The medication is considered relevant for easing the distress and temporary functional strain caused by the condition during difficult episodes. Applied in contexts where additional support for symptom management is needed, Cletus assists with maintaining functional stability and supports general well-being during symptomatic phases. It is often used when symptoms intensify and short-term supportive relief is needed to help patients maintain a sense of stability when symptoms become more noticeable.


Quick Fact: Relevant for Easing Walking Pain

Eligibility and Restrictions for Use

Who can and cannot use Cletus?

Cletus (Omeprazole) is defined for use by regulatory bodies through specific eligibility rules concerning hypersensitivity, concurrent medications, age, and underlying health conditions.


Category Regulatory Status Restriction Details
Absolute Contraindications Prohibited Known hypersensitivity to omeprazole or any substituted benzimidazoles. Co-administration with nelfinavir or atazanavir is also contraindicated.
Age-Group Eligibility Approved Established for use in adults and in children starting from one year of age for most conditions. Safety and efficacy are not established for infants younger than one month of age.
Organ Function Status Conditional Use Patients with impaired hepatic function may require a reduced daily dose due to altered drug clearance. Renal impairment typically requires no dose adjustment.
Pregnancy and Lactation Permitted / Acceptable Use during pregnancy is generally considered acceptable based on available epidemiological data. Low levels are excreted into breast milk, but are not expected to influence the infant when therapeutic doses are used.
Pre-treatment Screening Mandatory Exclusion The presence of gastric malignancy must be excluded before initiating Cletus therapy in patients with gastric ulcer symptoms, as the medicine may mask symptoms.

What should I know about interactions with other medicines?

Cletus (cilostazol) is a phosphodiesterase type 3 (PDE3) inhibitor used to reduce symptoms of intermittent claudication. It is important to discuss all other medications, supplements, and foods with your healthcare provider to manage potential interactions.

Medications that Increase Bleeding Risk

Because Cletus can affect blood clotting, taking it with other medications that increase the risk of bleeding may lead to a higher chance of hemorrhage or bruising. This includes:

  • Anticoagulants (blood thinners), such as warfarin.
  • Antiplatelet drugs, such as aspirin and clopidogrel.
  • Nonsteroidal Anti-Inflammatory Drugs (NSAIDs), such as ibuprofen and naproxen.

Medications Affecting Cletus Levels

Certain drugs can alter how Cletus is metabolized in the body, potentially leading to increased Cletus concentration and a higher risk of side effects. This group includes:

  • CYP3A4 inhibitors and CYP2C19 inhibitors, such as diltiazem (for high blood pressure), erythromycin (an antibiotic), and omeprazole (for stomach acid).

If you take any of these medications, your doctor may need to adjust your Cletus dosage.

Food and Other Products

  • Grapefruit Juice: Consuming large amounts of grapefruit juice should be avoided as it may increase the level of Cletus in your bloodstream, raising the risk of adverse effects.
  • Alcohol: Avoid or limit alcohol consumption, as it may increase the chance of dizziness and also increase the risk of side effects related to the liver.

Mechanism of Action

Cletus's mechanism of action is defined by a highly selective, irreversible inhibition of the gastric proton pump, the mathbfH^+/ mathbfK^+ -ATPase enzyme located in the parietal cells of the stomach lining. The active ingredient, Omeprazole, functions as a prodrug that must first diffuse into the highly acidic environment of the secretory canaliculi. Here, it undergoes protonation and chemical rearrangement to form the active sulfenamide metabolite.

This active metabolite subsequently forms a stable, covalent bond with accessible cysteine residues on the H^+ / K^+-ATPase. This binding permanently inactivates the enzyme, blocking the final extrusion of hydrogen ions ( H^+) into the stomach lumen, regardless of hormonal or neural stimulation. Since the drug only inhibits pumps that are actively secreting acid, maximum physiological inhibition is achieved cumulatively over several doses as the pump population cycles from resting to active states. The resulting physiological modulation is a significant and sustained rise in gastric pH that persists until the parietal cell synthesizes new, uninhibited H^+ / K^+-ATPase enzymes.

Dosage and Administration Information

Cletus, which contains the active ingredient cilostazol, is prescribed to reduce the symptoms of intermittent claudication, a condition caused by inadequate blood flow to the legs. It functions as a phosphodiesterase III inhibitor, working to prevent blood clots and widen the blood vessels, thereby increasing circulation to the lower limbs.

Administration and Dosing

  • The recommended standard dosage for Cletus is 100 mg twice daily.
  • It must be taken on an empty stomach, at least 30 minutes before or 2 hours after breakfast and dinner, with a glass of water.
  • The tablet should be swallowed whole; do not crush, break, or chew the tablet.
  • If you miss a dose, take it as soon as you remember. If it is nearly time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses simultaneously to make up for a missed one.

Important Considerations

  • Symptom improvement may begin as early as 2 to 4 weeks, but the maximum therapeutic benefit may require up to 12 weeks of continuous treatment. Your healthcare provider will assess your response after 3 months of therapy.
  • A dosage reduction to 50 mg twice daily may be required when Cletus is taken concurrently with certain medications that inhibit specific liver enzymes (CYP3A4 or CYP2C19), such as some antifungal agents or antibiotics.
  • Avoid consuming grapefruit or grapefruit juice, as it can increase the drug concentration in the body.
  • Cletus is contraindicated in patients with heart failure of any severity.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Cletus

The research for Cletus explores patterns observed in patients with conditions addressed by acid reduction, which is relevant in trials assessing short-term or episodic symptom patterns associated with acid-related conditions. The research helps contextualize how patients reported their experience and provides insight into short-term changes in symptoms and physical discomfort.


Evidence for Use in Healing Erosive Esophagitis (EE)

The primary evidence for this condition comes from Randomized Controlled Trials (RCTs) and systematic reviews involving adults and children with EE. These studies explored how the medicine was studied for changes in mucosal status (the absence of visible tissue breaks) and to measure the resolution of reflux symptoms such as heartburn. Findings describe patterns observed in the studies related to healing rates over typical acute treatment periods. Research also describes the patterns observed across different severity grades of esophagitis.

What remains uncertain is the long-term safety data for continuous use in certain pediatric age groups. While the medicine was studied for changes in mucosal status in this younger population, some studies have limited information for long-term outcomes specific to infants and young children.


Evidence for Use in Symptomatic Gastroesophageal Reflux Disease (GERD)

Research exploring symptoms of GERD without visible erosions (NERD) relied heavily on short-term, placebo-controlled RCTs. The outcomes monitored were primarily patient-reported outcomes describing perceived discomfort, such as the daily resolution of heartburn. Studies report how symptoms evolved in the observed populations, indicating that a subset of patients with NERD may experience a resolution of their outcomes related to physical discomfort during the study period.

Follow-up durations were limited in many of these studies. Consequently, evidence provides limited insight into long-term outcomes for patients with non-erosive GERD, and factors predicting who will or will not respond to the medication remain an area of ongoing investigation.


Gaps in Research and Areas of Uncertainty

Despite extensive research, the evidence landscape still contains areas of uncertainty. Evidence quality varies across studies concerning patients whose symptoms do not improve fully (refractory GERD), and subgroup findings are uncertain in this area. Furthermore, comparative evidence is lacking for certain head-to-head trials against newer medications in all patient groups. The results apply only to the populations studied and do not determine whether an individual will respond similarly.

Key Studies & References

  1. Omeprazole - StatPearls - NCBI Bookshelf
  2. Gastro-oesophageal reflux disease and dyspepsia in adults: investigation and management (CG184)

Frequently Asked Questions (FAQ)

Common questions about Cletus (FAQ)


Q: How quickly does Cletus start to work after the first dose?

Studies and official information indicate that the benefits of Cletus on symptoms may not be immediate. While some patients may notice improvement in as little as 2 to 4 weeks, the maximum therapeutic effect can require up to 12 weeks of continuous treatment. The maximum benefit is typically assessed after three months of continuous treatment.


Q: Can Cletus affect my ability to drive or operate machinery?

Regulatory information lists dizziness as a common side effect of Cletus. Because dizziness could impair concentration or coordination, patients are advised to note how they react to this medication before engaging in activities that require full mental alertness, such as driving or operating machinery.


Q: Is Cletus safe for older adults (seniors)?

Official product information suggests that older adults, typically those aged 50 to 80, do not require a special dosage adjustment. Studies on how the body handles the medicine (pharmacokinetics) found no significant difference in clearance for this age group compared to others.


Q: Can children or teenagers take Cletus?

According to regulatory labeling, the safety and effectiveness of Cletus have not been established for use in pediatric patients, including children and teenagers.


Q: Is Cletus safe for people who have kidney issues?

Official safety warnings state that Cletus is contraindicated (must not be used) by patients with severe renal impairment (very reduced kidney function). Patients with kidney issues are advised to consult their healthcare provider, as Cletus is not suitable in severe cases.


Q: Is it common for Cletus to cause headaches?

Yes, headaches are considered a very common side effect of Cletus. In clinical trials, this was one of the most frequently reported adverse reactions, affecting 10% or more of patients.


Q: Can Cletus affect blood sugar levels?

Post-marketing safety surveillance has included reports of changes in blood glucose (blood sugar) levels. This is an effect that has been reported, although the frequency of occurrence is not known from the primary clinical trials.


Q: Is Cletus a type of antibiotic or something else?

Cletus, which contains the active ingredient cilostazol, is not an antibiotic. It is classified as a Phosphodiesterase III Inhibitor (PDE3 inhibitor). This means it works to widen blood vessels and affect blood clotting.


Q: Can Cletus cause fatigue or drowsiness?

Drowsiness and a general feeling of tiredness or weakness (asthenia) have been documented as adverse reactions. While these effects are noted in post-marketing reports, their specific frequency is not well-established in clinical trial data.


Q: Is it safe to drink alcohol while taking Cletus?

Official product information advises that alcohol consumption should be avoided or limited. This is because alcohol may increase the chance of experiencing dizziness and could potentially increase the risk of side effects related to the liver.


Q: Does Cletus have a risk of withdrawal symptoms when stopped?

Available regulatory data suggest that when the medicine is stopped, there is no risk of a rebound effect where blood clotting increases quickly (platelet hyperaggregability). Discussions regarding stopping the medication should always take place with a healthcare professional.


Q: Can Cletus cause changes in appetite or weight?

Post-marketing safety surveillance includes reports of a loss of appetite. However, the exact frequency of this effect occurring among patients taking Cletus is not currently known.


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

Taking too much Cletus at once (an acute overdose) is anticipated to cause an exaggerated effect of the medicine. Regulatory documents list potential symptoms as severe headache, diarrhea, low blood pressure (hypotension), a very fast heart rate (tachycardia), and possible irregular heart rhythms (cardiac arrhythmias).


Q: Is Cletus available as a generic medicine?

Yes, the active ingredient, cilostazol, is available as a generic medicine. It is commonly supplied in the same strengths as the brand-name product, which are typically 50 mg and 100 mg tablets.


Q: Are there any long-term side effects associated with Cletus use?

Serious and rare adverse reactions have been reported over time, including heart attack (myocardial infarction), stroke (cerebrovascular accident), and severe blood disorders. These events are documented in the official safety profile for the medicine.


Q: Is it normal to feel nauseous when first starting Cletus?

Nausea is a frequently reported adverse reaction associated with Cletus. Additionally, vomiting has also been reported in post-marketing safety data.


Q: Can I take Cletus if I'm trying to get pregnant?

Cletus is contraindicated for use during pregnancy. Individuals who are planning a pregnancy should review the associated risks with their healthcare provider.


Q: What if Cletus doesn't seem to be working after a few weeks?

Symptom improvement may require up to 12 weeks of continuous treatment to reach maximum benefit. If there is no beneficial effect on symptoms after 3 months (12 weeks) of continuous treatment, patients are advised to consult their healthcare provider to discuss next steps.


Q: Does Cletus affect men and women differently?

Based on official pharmacokinetic studies, the way the body clears the medicine (clearance), when adjusted for body weight, was not found to be significantly different between male and female patients.


Q: Can Cletus cause temporary vision changes?

Post-marketing reports have included instances of blurred vision and temporary loss of vision (transient blindness). The specific frequency of these effects is not known.


Q: Is it common to have stomach upset from Cletus?

Yes, regulatory documents list several gastrointestinal issues as common adverse reactions, occurring in 1% to 10% of patients. These include indigestion (dyspepsia), abdominal pain, flatulence, and constipation.


Q: Are there different strengths or formulations of Cletus available?

Yes, Cletus (cilostazol) is supplied as tablets in two different strengths. These are available in 50 mg and 100 mg forms.


Q: What should I tell my doctor about before starting Cletus?

Regulatory documents outline key medical conditions and risks that should be reviewed with a physician. These include the presence of heart failure of any severity, any predisposition to bleeding or active bleeding, and known or suspected hypersensitivity to the drug's components.


Q: Do people typically feel better immediately after starting Cletus?

The beneficial effects on symptoms are generally not immediate, as it may take 2 to 4 weeks to notice any improvement. The full therapeutic effect is a gradual process that can take up to 12 weeks.

How should Cletus be stored and disposed of?

Cletus (Cilostazol) must be stored and handled according to regulatory labeling to maintain its stability and effectiveness.


Storage Requirements

Cletus must be stored at Controlled Room Temperature (20 C to 25 C / 68 F to 77 F). It is essential to keep the medicine in the original container and ensure the container is tightly closed to protect the contents from moisture and light. The product must be stored out of the sight and reach of children and protected from freezing and excessive heat.


Disposal Instructions

Do not flush unused or expired Cletus down the toilet or pour it into a drain. The preferred method for disposal is utilizing a drug take-back program. If one is unavailable, the medicine should be mixed with an unappealing substance, placed in a sealed bag, and discarded with household trash.

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

Available in countries:

Equivalent of Cletus found in:

A-Z Index: