The white capsule-shaped pill debossed with TCL 341 is Acetaminophen 500 mg (Extra Strength), manufactured by Time Cap Laboratories, Inc. It is an over-the-counter (OTC) analgesic and antipyretic equivalent to Extra Strength Tylenol, commonly used to treat headaches, minor musculoskeletal pain, arthritis discomfort, toothaches, and fever
Pill Identification
Attribute – Specification
- Active Ingredient – Acetaminophen USP (500 mg)
- Imprint – TCL 341 (single-sided, unscored)
- Color & Shape – White, capsule-shaped (oblong, film-coated)
- Size – ~17 mm
- Drug Class – Miscellaneous analgesics / antipyretics
- Regulatory Status – Over-the-counter (OTC) / Non-controlled substance
- Packager / Manufacturer – Time Cap Laboratories, Inc. (NDC 49483-341)
Mechanism of Action
Acetaminophen differs fundamentally from nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen because it produces negligible peripheral anti-inflammatory action:
- Central Prostaglandin Inhibition: Acetaminophen selectively inhibits cyclooxygenase enzymes in tissues with low concentrations of cellular peroxides, such as the brain and spinal cord. At peripheral sites of inflammation, leukocytes release high peroxide levels that neutralize this inhibitory effect, which is why acetaminophen does not relieve local swelling.
- Antipyretic Action: By blocking prostaglandin synthesis in the preoptic area of the anterior hypothalamus, it resets the body’s elevated temperature set-point, driving heat loss through cutaneous vasodilation and sweating.
- Cannabinoid & Serotonergic Pathway Involvement: In the liver and brain, a small fraction of acetaminophen is metabolized into aminophenol, which conjugates with arachidonic acid to form AM404. AM404 inhibits the reuptake of the endocannabinoid anandamide and activates receptors, reinforcing descending inhibitory serotonergic pathways in the spinal cord that suppress pain signaling.
Dosage and Administration
To prevent liver toxicity, always adhere strictly to labeled OTC dosing parameters:
- Adults and Children 12 Years:
- Standard Dose: 1 to 2 caplets (500 mg to 1,000 mg) orally every 4 to 6 hours as needed while symptoms persist.
- Daily Maximum: Do not exceed 6 caplets (3,000 mg) within 24 hours under standard self-care OTC guidelines (the absolute clinical upper safety limit is 4,000 mg/24 hours under medical supervision).
- Use Duration: Discontinue use and consult a physician if pain lasts longer than 10 days, or if fever persists for more than 3 days.
- Children Under 12 Years: Do not administer this adult-strength solid formulation without pediatric guidance; weight-appropriate pediatric oral suspensions or chewable tablets are required.
- Administration: Swallow whole with a glass of water, with or without food. Taking it on an empty stomach may lead to faster analgesic onset.
Common and Serious Side Effects
At therapeutic doses, acetaminophen is gentle on the stomach and does not impair platelet aggregation.
Mild / Infrequent Effects:
- Mild nausea, abdominal cramping, or constipation
- Lightheadedness or mild headache
Severe Adverse Reactions (Seek Immediate Medical Care):
- Acute Hepatotoxicity: Yellowing of the skin or eyes (jaundice), dark or tea-colored urine, pale stools, severe fatigue, loss of appetite, or pain in the upper right quadrant of the abdomen.
- Severe Skin Reactions: Acetaminophen can trigger rare but life-threatening dermatological emergencies, including Stevens-Johnson syndrome (SJS), Toxic Epidermal Necrolysis (TEN), and Acute Generalized Exanthematous Pustulosis (AGEP). Stop the medication immediately if skin reddening, blisters, or a spreading rash develops.
- Hypersensitivity / Anaphylaxis: Facial swelling (lips, tongue, throat), hives, or difficulty breathing.
Precautions and Drug Interactions
- Combination Products (Double-Dosing): Acetaminophen is a component of hundreds of multi-symptom cold/flu remedies, sinus decongestants, sleep aids, and prescription opioid combinations (such as Percocet or Norco). Check all active ingredients to avoid inadvertently exceeding the 3,000–4,000 mg daily maximum.
- Alcohol Intake: Consuming 3 or more alcoholic drinks daily significantly increases the risk of severe liver damage by depleting hepatic glutathione reserves and inducing the enzyme .
- Anticoagulants (Warfarin): Prolonged regular use of acetaminophen (2,000 mg per day over several days) can reduce warfarin clearance and elevate International Normalized Ratio (INR), increasing the risk of bleeding.
- Pre-existing Hepatic Disease: Individuals with cirrhosis, chronic viral hepatitis, or significant liver impairment should consult a doctor before using acetaminophen
Overdose Toxicity and Warnings
- Boxed Warning: Liver Damage
- Hepatic metabolism of acetaminophen produces a minor reactive intermediate known as benzoquinone imine (NAPQI). Under standard dosing, NAPQI is rapidly conjugated and detoxified by liver glutathione. In an overdose, glutathione reserves are exhausted, allowing excess unbound NAPQI to bind to hepatic macromolecules, causing acute centrilobular liver necrosis.
- Emergency Overdose Protocol: Symptoms during the first 24 hours can be deceivingly mild (nausea, lethargy, loss of appetite) despite active liver injury. If an overdose is suspected, immediately contact Poison Control (1-800-222-1222 in the US) or emergency services.
- Antidote: acetylcysteine (NAC) acts as a direct precursor to restore glutathione stores; it is nearly 100% effective at preventing severe liver failure when administered within 8 to 10 hours of acute ingestion.