What is the S500 pill used for? Understanding the 500mg Acetaminophen Tablet

October 6, 2025 •

4 min read

According to reputable pill identifiers, a white, oval pill imprinted with 'S 500' is most commonly 500 mg of acetaminophen, a widely used over-the-counter pain reliever and fever reducer. So, what is the S500 pill used for, and what should you know before taking it?

Quick Summary

A white, oval pill imprinted 'S 500' is typically a 500mg acetaminophen tablet, used for relieving minor aches, pains, and reducing fever. Proper identification and dosage are crucial for safe use.

Key Points

Active Ingredient: The S500 pill is most commonly 500mg acetaminophen, a common pain reliever and fever reducer.
Common Uses: It treats a variety of conditions, including headaches, backaches, muscle pain, menstrual cramps, arthritis, and fever.
Dosage: For adults, typical Extra Strength dosage is two caplets every six hours, but the total daily amount must not exceed 4,000 mg.
Liver Warning: Taking too much acetaminophen or combining it with alcohol can cause serious and potentially fatal liver damage.
Accurate Identification: Be aware that other pills may have similar 'S500' imprints, so verify the pill's shape, color, and manufacturer, or consult a pharmacist.
Differences from Ibuprofen: Unlike NSAIDs like ibuprofen, acetaminophen does not reduce inflammation and has a different set of precautions and side effects.

S500 Pill: Active Ingredient and Formulation

For many, an unidentified pill can cause concern. However, based on information from major drug databases, a white, oval-shaped pill with the marking 'S 500' is identified as acetaminophen 500 mg. Acetaminophen, also known as paracetamol outside of the United States, is the active ingredient. It is a common analgesic (pain reliever) and antipyretic (fever reducer). This medication works by changing how the body senses pain and by helping to cool the body to lower a fever. Because it is available over-the-counter (OTC) and in numerous prescription combination products, it is one of the most frequently used medications in the world.

Common Conditions Treated by Acetaminophen 500 mg

The S500 pill, as a 500 mg acetaminophen tablet, is used to treat a variety of minor to moderate pain symptoms and to reduce fever. Its widespread use is a testament to its effectiveness for many common ailments. Common uses for this medication include:

Headaches: Both tension-type headaches and, in combination with other medications, migraine headaches.
Muscle Aches: Pain and soreness from exercise, strains, and everyday activities.
Menstrual Cramps: Relief from the discomfort associated with a woman's monthly cycle.
Minor Pain of Arthritis: Symptom management for the pain of osteoarthritis.
Backaches: Alleviation of minor back pain.
Toothaches: Temporary relief of pain related to dental issues.
Fever: Reduction of fever associated with the common cold, flu, and other illnesses.
Symptoms of Colds and Flu: Easing general aches and pains that accompany viral infections.

Important Precautions and Potential Side Effects

While generally safe when used as directed, acetaminophen is not without risks. The most critical risk is potential liver damage, especially if an overdose occurs or if the medication is taken with alcohol. It is crucial to adhere strictly to recommended dosages and to be aware of other medications containing acetaminophen to avoid accidental overdose.

Common side effects are rare but may include:

Nausea
Rash or itching
Upset stomach
Headache

Serious side effects requiring immediate medical attention include:

Signs of liver problems, such as upper stomach pain, loss of appetite, dark urine, or yellowing of the skin or eyes (jaundice).
Severe skin reactions, including redness, peeling, or blistering.
Swelling of the face, throat, tongue, lips, or extremities.
Difficulty breathing or swallowing.

Comparison of Acetaminophen and Ibuprofen

Understanding the differences between common pain relievers is important for making informed health decisions. The table below compares acetaminophen (S500 pill) and ibuprofen, another popular OTC pain medication.


Feature	Acetaminophen (S500)	Ibuprofen (e.g., Advil, Motrin)
Mechanism of Action	Changes how the body senses pain and reduces fever by acting on the central nervous system.	A nonsteroidal anti-inflammatory drug (NSAID) that reduces hormones that cause pain and inflammation throughout the body.
Primary Uses	Pain relief (analgesic) and fever reduction (antipyretic).	Pain relief, fever reduction, and anti-inflammatory effects.
Inflammation	Does not reduce inflammation.	Effective for reducing inflammation, making it useful for conditions like arthritis and strains.
Stomach Effects	Generally gentler on the stomach than NSAIDs.	Can cause stomach irritation, bleeding, or ulcers, especially with prolonged use or high doses.
Liver vs. Kidney	Metabolized primarily by the liver; high doses can cause liver damage.	Metabolized primarily by the kidneys; can affect kidney function, especially in at-risk individuals.
Drug Interactions	May interact with blood thinners like warfarin.	Interacts with numerous medications, including blood thinners, certain blood pressure drugs, and diuretics.

Safe Use and Dosage Guidelines

Following correct dosage instructions is paramount for the safe use of acetaminophen. Always read the product label carefully, as it contains specific directions for adults and children. For the 500 mg (Extra Strength) formulation, typical adult dosage is to take two caplets every six hours, not exceeding six caplets in 24 hours unless directed by a doctor.

Key safety guidelines include:

Do not exceed the daily limit: The maximum adult daily dose for acetaminophen is 4,000 mg (4 grams). This applies to all sources of acetaminophen combined, including OTC, prescription, and combination products. Always check the labels of any other medications you take.
Limit alcohol intake: Avoid or limit alcohol consumption while taking acetaminophen, as it significantly increases the risk of liver damage.
Consult a doctor: If you have liver disease or are taking the blood-thinning drug warfarin, consult a doctor or pharmacist before use.
Pediatric use: Do not use adult-strength acetaminophen for children under 12 years of age without medical guidance. Pediatric doses are based on weight and age and should be measured using the correct device provided with the product.

Other S500 Pill Identifications

While the white, oval 'S 500' pill is most commonly associated with 500 mg acetaminophen, it's important to be aware that other pills may have similar imprints. For example, a white, round pill with 'S 500' could be Ketoconazole 200 mg, an antifungal medication. To ensure proper identification, always check multiple identifiers, including pill shape, color, and size, or consult a pharmacist. Pill identification websites like Drugs.com and Medicine.com provide images and detailed descriptions to assist with this process.

Conclusion

To answer the question, what is the S500 pill used for, the most common identification points to an Extra Strength 500mg acetaminophen tablet. This medication is a safe and effective over-the-counter treatment for minor aches, pains, and fever when used as directed. However, due to the risk of liver damage from overdose or combining it with alcohol, and the existence of other similarly marked pills, caution and careful adherence to dosage instructions are essential. For any uncertainty, always consult a healthcare professional. For more details on acetaminophen, refer to MedlinePlus' comprehensive drug information.

Frequently Asked Questions

The S500 pill is a 500mg acetaminophen tablet, and its primary function is to relieve minor to moderate pain and reduce fever.

The 500mg acetaminophen tablet is typically an over-the-counter (OTC) medication. It is available without a prescription but can also be found in many prescription combination products.

It is strongly advised to avoid drinking alcohol while taking acetaminophen, as this combination significantly increases the risk of liver damage.

An overdose of acetaminophen can be fatal. If you suspect an overdose, you should seek emergency medical attention immediately, even if you are not experiencing symptoms.

To properly identify a pill, you should check its imprint code, shape, color, and size. While a white, oval 'S 500' is often acetaminophen, other pills with the same imprint but different shapes exist, like a round antifungal tablet. Always use a reliable pill identifier or ask a pharmacist for help.

Side effects are rare with correct usage, but some people may experience minor issues like nausea, rash, or upset stomach. Severe allergic reactions or signs of liver damage are serious but uncommon side effects that require immediate medical help.

For simple pain and fever, both are effective. However, for conditions involving inflammation (like strains or arthritis), ibuprofen's anti-inflammatory properties may be more beneficial. If you have concerns about liver or kidney function, stomach sensitivity, or drug interactions, consult a healthcare professional for the best option.