Acetaminophen
(generic name) or Tylenol (brand name)
Always keep track of dose
taken. Taking over 4 grams (4000mg) in a 24-hour period may lead to liver
failure. Up to 40% of patients currently awaiting liver transplant are due to
acetaminophen toxicity.
If you take acetaminophen, or
acetaminophen containing medications (e.i.: Darvocet,
Tylenol#3, Tylenol with codeine, Vicodin, Tylox, Percocet, Zydone, Norco,
etc.), on a daily basis, your liver may be susceptible to damage at lower
doses. Some recent studies suggest that doses as low as 2.9 grams (2900 mg) per
day, may cause liver necrosis (permanent damage = Liver failure).
Acetaminophen (Tylenol)
Apap (Tylenol)
Paracetamol (Tylenol)
Acetaminophen
(ah-SEAT-ah-MIN-oh-fen)
Classification: Nonnarcotic analgesic,
para-aminophenol type
Action/Kinetics: Decreases fever by an effect on the hypothalamus
leading to sweating and vasodilation. It also inhibits the effect of pyrogens
on the hypothalamic heat-regulating centers. May cause analgesia by inhibiting
CNS prostaglandin synthesis; however, due to minimal effects on peripheral
prostaglandin synthesis, acetaminophen has no anti-inflammatory or uricosuric
effects. Does not cause any anticoagulant effect or ulceration of the GI tract.
Antipyretic and analgesic effects are comparable to those of aspirin.
Peak plasma levels: 30-120 min.
Therapeutic serum levels (analgesia): 5-20 mcg/mL.
Plasma protein binding: Approximately 25%. Metabolized in the liver and
excreted in the urine as glucuronide and sulfate conjugates. However, an
intermediate hydroxylated metabolite is hepatotoxic following large doses of
acetaminophen.
The extended-relief product uses a bilayer system that allows the outer layer
to release acetaminophen rapidly while the inner layer is designed to release
the remainder of the dose more slowly. This allows prolonged relief of
symptoms.
The buffered product is a mixture of acetaminophen, sodium bicarbonate, and
citric acid that effervesces when placed in water. This product has a high
sodium content (0.76 g/3/4 capful).
Uses: Control of pain due to headache, earache, dysmenorrhea,
arthralgia, myalgia, musculoskeletal pain, arthritis, immunizations, teething,
tonsillectomy. To reduce fever in bacterial or viral infections. As a
substitute for aspirin in upper GI disease, aspirin allergy, bleeding
disorders, clients on anticoagulant therapy, and gouty arthritis. Investigational:
In children receiving diptheria-pertussis-tetanus vaccination to decrease incidence
of fever and pain at injection site.
Contraindications: Renal insufficiency, anemia. Clients with cardiac or
pulmonary disease are more susceptible to toxic effects of acetaminophen.
Special Concerns: May have to be used with caution in pregnancy. Heavy
drinking and fasting may be risk factors for acetaminophen toxicity, especially
if larger than recommended doses of acetaminophen are used. As little as twice
the recommended dosage, over time, can lead to serious liver damage.
Side Effects: Few when taken in usual therapeutic doses. Chronic and
even acute toxicity can develop after long symptom-free usage. Hematologic: Methemoglobinemia,
hemolytic anemia
neutropenia, thrombocytopenia, pancytopenia, leukopenia. Allergic:
Urticarial and erythematous skin reactions, skin eruptions, fever. Miscellaneous:
CNS stimulation, hypoglycemic coma, jaundice, drowsiness, glossitis. Possible
liver damage in those who consume three or more alcoholic drinks daily.
Overdose Management: Symptoms: May be no early specific symptoms.
Within first 24 hr: N&V, diaphoresis, anorexia, drowsiness, confusion,
liver tenderness, cardiac arrhythmias, low BP, jaundice, acute hepatic and
renal failure. Within 24-48 hr, increased AST, ALT, bilibrubin,
prothrombin levels. After 72-96 hr, peak hepatotoxicity with death possible due
to liver necrosis. Treatment: Initially, induction of emesis, gastric
lavage, activated charcoal. Oral N-acetylcysteine is said to reduce or
prevent hepatic damage by inactivating acetaminophen metabolites, which cause
liver toxicity.
Drug Interactions:
Alcohol, ethyl: Chronic use increases toxicity of larger therapeutic doses of acetaminophen
Barbiturates: Increased potential of hepatotoxicity due to increased liver breakdown of acetaminophen
Carbamazepine: Increases potential of hepatotoxicity due to increased breakdown of acetaminophen by liver
Charcoal, activated: Decreases absorption of acetaminophen when given as soon as possible after overdose
Diuretics, loop: Decrease Effect due to decreased renal prostaglandin excretion and decreased plasma renin activity
Hydantoins (including Phenytoin): Increase potential of hepatotoxicity due to increased breakdown of acetaminophen by liver
Isoniazid: Increases potential of hepatotoxicity due to increased breakdown of acetaminophen by liver
Lamotrigene: Decreases serum lamotrigene levels leading to decreased effect
Milk thistle: Helps prevent liver damage from acetaminophen.
Oral contraceptives: Increase liver breakdown of acetaminophen therefore decreasing the half-life.
Propranolol: Decrease effect due
to decreased breakdown by liver.
Rifampin: Increases potential
of hepatotoxicity due to increased breakdown of acetaminophen by liver.
Sulfinpyrazone: Increase potential
of hepatotoxicity due to decreased breakdown of acetaminophen by liver.
AZT: Decreased sffect of AZT due to increased nonhepatic or renal clearance
How Supplied:
Dosage
Caplets,
Capsules, Chewable Tablets, Gelcaps, Elixir, Oral Liquid, Oral Solution, Oral
Suspension, Sprinkle Capsules, Syrup, Tablets Analgesic, antipyretic.
Adults: 325-650 mg q 4 hr; doses up to 1 g q.i.d. may be used. Daily
dosage should not exceed 4 g. Pediatric: Doses given 4-5 times/day. Up
to 3 months: 40 mg/dose; 4-11 months: 80 mg/dose; 1-2 years: 120
mg/dose; 2-3 years: 160 mg/dose; 4-5 years: 240 mg/dose; 6-8
years: 320 mg/dose; 9-10 years: 400 mg/dose; 11 years: 480
mg/dose. 12-14 years: 640 mg/dose. Over 14 years: 650 mg/dose. Alternative
pediatric dose: 10-15 mg/kg q 4 hr.
Extended
Relief Caplets Analgesic,
antipyretic.
Adults: 2 caplets (1,300 mg) q 8 hr.
Suppositories Analgesic, antipyretic.
Adults: 650 mg q 4 hr, not to exceed 4 g/day for up to 10 days. Clients
on long-term therapy should not exceed 2.6 g/day. Pediatric, 3-11 months: 80
mg q 6 hr. 1-3 years: 80 mg q 4 hr; 3-6 years: 120-125 mg q 4-6
hr, with no more than 720 mg in 24 hr. 6-12 years: 325 mg q 4-6 hr with
no more than 2.6 g in 24 hr. Dosage should be given as needed while symptoms
persist.
Buffered
Analgesic, antipyretic.
Adult, usual: 1 or 2 three-quarter capfuls are placed into an empty
glass; add half a glass of cool water. May be taken while fizzing or after
settling. Can be repeated q 4 hr as required or directed by provider.