Effects of Continual Use of Tylenol

What is Tylenol (acetaminophen) and what is it used for?

Tylenol (acetaminophen) is an analgesic (pain reliever) and antipyretic (fever reducer) to relieve fever as well as aches and pains associated with many conditions. Tylenol relieves pain in mild arthritis but has no effect on the underlying inflammation, redness, and swelling of the joint. If the pain is not due to inflammation, Tylenol is as effective as aspirin. Tylenol is, however, as effective as the non-steroidal anti-inflammatory drug (NSAID) ibuprofen (Motrin) in relieving pain due to osteoarthritis of the knee. When used appropriately, side effects with Tylenol are not common.

When they do occur side effects of Tylenol include rash, nausea, and headache.

Other important side effects of Tylenol include

hypersensitivity reactions,
serious skin reactions,
kidney damage,
anemia, and
low platelets in the blood (thrombocytopenia).

Chronic alcohol use may increase the risk of stomach bleeding. The most serious side effect of Tylenol is liver damage due to large doses, chronic use or concomitant use with alcohol or other drugs that also damage the liver. Other serious side effects of Tylenol include

bleeding in the intestines and stomach,
angioedema,
Stevens-Johnson syndrome,
kidney damage, and
reduced white blood cell counts.

Drug interactions of Tylenol include carbamazepine, isoniazid, rifampin, alcohol, cholestyramine, and warfarin.

Tylenol is often used during pregnancy for short-term treatment of fever and minor pain during pregnancy. Tylenol is excreted in breast milk in small quantities, however, use by nursing mothers appears to be safe.

What are the important side effects of Tylenol (acetaminophen)?

When used appropriately, side effects with acetaminophen are not common.

The most common side effects are rash, nausea, and headache.

Other important side effects include:

Hypersensitivity reactions
Serious skin reactions
Kidney damage
Anemia
Reduced number of platelets in the blood (thrombocytopenia)

Chronic alcohol use may also increase the risk of stomach bleeding. The most serious side effect is liver damage due to large doses, chronic use or concomitant use with alcohol or other drugs that also damage the liver.

Other serious side effects that have been reported include bleeding in the intestines and stomach, angioedema, Stevens-Johnson syndrome, and kidney damage. A reduction in the number of white blood cells has also been reported.

Tylenol (acetaminophen) side effects list for healthcare professionals

The following serious adverse reactions are discussed elsewhere in the labeling:

Hepatic Injury
Serious Skin Reactions
Allergy and Hypersensitivity

Clinical Trial Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed cannot be directly compared to rates in other clinical trials and may not reflect the rates observed in practice.

Adult Population

A total of 1,020 adult patients have received acetaminophen in clinical trials, including 37.3% (n=380) who received 5 or more doses, and 17% (n=173) who received more than 10 doses. Most patients were treated with acetaminophen 1,000 mg every 6 hours. A total of 13.1% (n=134) received acetaminophen 650 mg every 4 hours.

All adverse reactions that occurred in adult patients treated with either acetaminophen or placebo in repeated dose, placebo-controlled clinical trials at an incidence = 3% and at a greater frequency than placebo are listed in Table 3. The most common adverse events in adult patients treated with acetaminophen (incidence = 5% and greater than placebo) were nausea, vomiting, headache, and insomnia.

Table 3. Treatment-Emergent Adverse Reactions Occurring = 3% in Acetaminophentreated Patients and at a greater frequency than Placebo in Placebo-Controlled, Repeated Dose Studies
System Organ Class - Preferred Term	Acetaminophen (N=402) n (%)	Placebo (N=379) n (%)
Gastrointestinal Disorders Nausea Vomiting	138 (34) 62 (15)	119 (31) 42 (11)
General Disorders and Administration Site Conditions Pyrexia*	22 (5)	52 (14)
Nervous System Disorders Headache	39 (10)	33 (9)
Psychiatric Disorders Insomnia	30 (7)	21 (5)
* Pyrexia adverse reaction frequency data is included in order to alert healthcare practitioners that the antipyretic effects of acetaminophen may mask fever.

Other Adverse Reactions Observed During Clinical Studies of Acetaminophen in Adults

The following additional treatment-emergent adverse reactions were reported by adult subjects treated with acetaminophen in all clinical trials (n=1,020) that occurred with an incidence of at least 1% and at a frequency greater than placebo (n=525).

Blood and lymphatic system disorders: anemia

General disorders and administration site conditions: fatigue, infusion site pain, edema peripheral

Investigations: aspartate aminotransferase increased, breath sounds abnormal

Metabolism and nutrition disorders: hypokalemia

Musculoskeletal and connective tissue disorders: muscle spasms, trismus

Psychiatric disorders: anxiety

Respiratory, thoracic and mediastinal disorders: dyspnea

Vascular disorders: hypertension, hypotension

Pediatric Population

A total of 355 pediatric patients (47 neonates, 64 infants, 171 children, and 73 adolescents) have received acetaminophen in active-controlled (n=250) and open-label clinical trials (n=225), including 59.7% (n=212) who received 5 or more doses and 43.1% (n=153) who received more than 10 doses. Pediatric patients received acetaminophen doses up to 15 mg/kg on an every 4 hours, every 6 hours, or every 8 hours schedule. The maximum exposure was 7.7, 6.4, 6.8, and 7.1 days in neonates, infants, children, and adolescents, respectively.

The most common adverse events (incidence = 5%) in pediatric patients treated with acetaminophen were nausea, vomiting, constipation, pruritus, agitation, and atelectasis.

Other Adverse Reactions Observed During Clinical Studies of Acetaminophen in Pediatrics

The following additional treatment-emergent adverse reactions were reported by pediatric subjects treated with acetaminophen (n=355) that occurred with an incidence of at least 1%.

Blood and lymphatic system disorders: anemia

Cardiac disorders: tachycardia

Gastrointestinal disorders: abdominal pain, diarrhea

General disorders and administration site conditions: injection site pain, edema peripheral, pyrexia

Investigations: hepatic enzyme increase

Metabolism and nutrition disorders: hypoalbuminemia, hypokalemia, hypomagnesemia, hypophosphatemia, hypervolemia

Musculoskeletal and connective tissue disorders: muscle spasm, pain in extremity

Nervous system disorders: headache

Psychiatric disorders: insomnia

Renal and urinary disorders: oliguria

Respiratory, thoracic and mediastinal disorders: pulmonary edema, hypoxia, pleural effusion, stridor, wheezing

Skin and subcutaneous tissue disorders: periorbital edema, rash

Vascular disorders: hypertension, hypotension

What drugs interact with Tylenol (Acetaminophen)?

Effects of Other Substances on Acetaminophen

Substances that induce or regulate hepatic cytochrome enzyme CYP2E1 may alter the metabolism of acetaminophen and increase its hepatotoxic potential. The clinical consequences of these effects have not been established. Effects of ethanol are complex, because excessive alcohol usage can induce hepatic cytochromes, but ethanol also acts as a competitive inhibitor of the metabolism of acetaminophen.

Anticoagulants

Chronic oral acetaminophen use at a dose of 4,000 mg/day has been shown to cause an increase in international normalized ratio (INR) in some patients who have been stabilized on sodium warfarin as an anticoagulant. As no studies have been performed evaluating the short-term use of acetaminophen in patients on oral anticoagulants, more frequent assessment of INR may be appropriate in such circumstances.

Summary

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Related Disease Conditions

Lower Back Pain (Lumbar Spine Pain)

There are many causes of back pain. Pain in the low back can relate to the bony lumbar spine, discs between the vertebrae, ligaments around the spine and discs, spinal cord and nerves, muscles of the low back, internal organs of the pelvis, and abdomen, and the skin covering the lumbar area.
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Knee Pain

Acute injuries, medical conditions, and chronic use conditions are causes of knee pain. Symptoms and signs that accompany knee pain include redness, swelling, difficulty walking, and locking of the knee. To diagnose knee pain, a physician will perform a physical exam and also may order X-rays, arthrocentesis, blood tests, or a CT scan or MRI. Treatment of knee pain depends upon the cause of the pain.
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Foot Pain

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Neck Pain (Cervical Pain)

Neck pain (cervical pain, cervicalgia) may be caused by any number of disorders and diseases. Tenderness is another symptom of neck pain. Though treatment for neck pain really depends upon the cause, treatment typically may involve heat/ice application, traction, physical therapy, cortisone injection, topical anesthetic creams, and muscle relaxants.
Hip Pain

Arthritis, bursitis, IT band syndrome, fracture, and strain are just some of the causes of hip pain. Associated symptoms and signs include swelling, tenderness, difficulty sleeping on the hip, and loss of range of motion of the hip. Treatment depends upon the cause of the hip pain but may include anti-inflammatory medications and icing and resting the hip joint.
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Elbow Pain

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Chronic Pain

Chronic pain is pain (an unpleasant sense of discomfort) that persists or progresses over a long period of time. In contrast to acute pain that arises suddenly in response to a specific injury and is usually treatable, chronic pain persists over time and is often resistant to medical treatments.