The white pill debossed with the imprint TCL 341 (often referred to as an oblong caplet or tablet) is an over-the-counter (OTC) extra-strength analgesic and antipyretic containing Acetaminophen (500 mg). It is a generic bioequivalent formulation to brand-name Extra Strength Tylenol.
Pill Identification
Attribute – Specification
- Active Ingredient – Acetaminophen, USP (500 mg per caplet/tablet)
- Imprint – TCL 341 debossed on one side; plain on the reverse
- Color & Shape – White, oblong / oval (caplet-shaped), film-coated
- Size – Approximately 17 mm
- Primary Manufacturer / Labeler – Time Cap Laboratories, Inc. (Timely Brands)
- Drug Class – Non-opioid, non-salicylate analgesic and antipyretic
- Availability – Over-the-counter (OTC)
- (Note: While some round tablets feature the isolated number “341”, such as Benazepril 5 mg, the TCL 341 imprint specifically designates the Time Cap Laboratories Acetaminophen 500 mg formulation).
Mechanism of Action
Acetaminophen (chemically known as paracetamol or aminophenol / APAP) provides pain relief and reduces fever through distinct central pathways rather than peripheral anti-inflammatory action:
- Central Prostaglandin Inhibition: Acetaminophen acts predominantly in the central nervous system (CNS). It inhibits the cyclooxygenase enzyme system—specifically reducing the peroxidase active site of thereby suppressing the central synthesis of pro-inflammatory and pain-signaling prostaglandin . Unlike nonsteroidal anti-inflammatory drugs (NSAIDs), it lacks significant peripheral anti-inflammatory effects because high levels of peripheral cellular peroxides present in inflamed tissues neutralize its enzymatic inhibition.
- Hypothalamic Thermoregulation: By blocking synthesis in the anterior hypothalamic thermoregulatory center, acetaminophen resets the body’s physiological thermostat. This promotes peripheral vasodilation and increased cutaneous blood flow, inducing diaphoresis (sweating) to dissipate body heat and lower fever.
- Endocannabinoid and Serotonergic Synergy: Acetaminophen is metabolized in neural tissues by fatty acid amide hydrolase (FAAH) into AM404. AM404 acts as an indirect cannabinoid receptor activator and stimulates receptors, reinforcing descending spinal serotonergic inhibitory pathways to elevate the systemic pain threshold.
Indications and Clinical Uses
- Mild to Moderate Pain Relief: Temporarily relieves headaches, tension headaches, muscular aches, backaches, toothaches, minor pain of arthritis, and premenstrual/menstrual cramps.
- Antipyresis: Temporarily reduces fever associated with viral or bacterial illnesses (such as the common cold or influenza).
Dosage and Administration
- Dosing guidelines must be strictly observed. Cumulative daily intake of acetaminophen from all sources (including prescription combinations and OTC remedies) should never exceed 4,000 mg in 24 hours (many OTC manufacturers advise a maximum of 3,000 mg per day to maximize safety).
- Adults and Children 12 Years of Age and Older:
- Standard Dose: Take 2 caplets (1,000 mg) orally every 6 hours while symptoms persist.
- Maximum Limit: Do not exceed 6 caplets (3,000 mg) in 24 hours unless directed by a physician.
- Duration Limits: Do not use for more than 10 days for pain or 3 days for fever without medical evaluation.
- Children Under 12 Years: Do not administer this adult-strength tablet; consult a pediatrician for weight-based pediatric liquid or chewable suspensions.
- Administration: Swallow whole with a full glass of water. Can be taken with or without food.
Side Effects
- Mild / Infrequent Effects (at recommended therapeutic doses):
- Minor nausea or stomach upset
- Mild headache or insomnia
Serious Adverse Reactions:
- Acute Hepatotoxicity & Liver Failure: Ingestion of excess doses saturates normal hepatic metabolic pathways (glucuronidation and sulfation), forcing metabolism through cytochrome P450 enzymes (mainly CYP2E1). This generates high amounts of the toxic intermediate benzoquinone imine (NAPQI). Once hepatic glutathione is exhausted, NAPQI covalently binds to hepatocytes, triggering centrilobular liver necrosis and potentially fatal acute liver failure.
- Severe Cutaneous Adverse Reactions (SCAR): Rare, life-threatening skin reactions, including Stevens-Johnson syndrome (SJS), Toxic Epidermal Necrolysis (TEN), and Acute Generalized Exanthematous Pustulosis (AGEP).
- Hypersensitivity Reactions: Urticaria (hives), facial or throat angioedema, and respiratory difficulty.
Key Drug Interactions
- Alcohol: Consuming 3 or more alcoholic beverages daily while taking acetaminophen significantly accelerates hepatic CYP2E1 enzyme activity and depletes glutathione stores, dramatically increasing the risk of severe, irreversible liver damage.
- Other Acetaminophen-Containing Products: Co-administration with prescription pain medications (e.g., Norco, Percocet) or multi-symptom cold/cough remedies can lead to inadvertent toxic overdose.
- Warfarin (Oral Anticoagulants): Chronic, daily use of high-dose acetaminophen (greater than 2,000 mg/day for several consecutive days) can potentiate the anticoagulant effect of warfarin, elevating the International Normalized Ratio (INR) and bleeding risk.
- CYP2E1 Inducers: Medications such as carbamazepine, phenytoin, phenobarbital, and rifampin can increase the rate at which acetaminophen is converted into toxic NAPQI.
Warnings and Precautions
- Liver Warning (FDA Boxed Category): Taking more than 4,000 mg in 24 hours, taking alongside other medications containing acetaminophen, or consuming 3+ alcoholic drinks per day can cause severe liver damage or death.
- Severe Skin Alert: Discontinue the medication immediately and seek emergency medical care at the first sign of skin reddening, rash, or blistering.
- Pre-existing Liver Disease: Patients diagnosed with cirrhosis, hepatitis, or impaired liver function should consult a physician before using acetaminophen.
- Overdose Management: In suspected overdose scenarios, seek emergency medical assistance or contact a Poison Control Center immediately, even if no initial symptoms are apparent. Early administration of the specific antidote acetylcysteine (NAC) (ideally within 8 hours of ingestion) replenishes glutathione stores and prevents acute hepatic necrosis.