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5 Interactions found for:

tizanidine and Tylenol
Interactions Summary
  • 2 Major
  • 0 Moderate
  • 3 Minor
  • tizanidine
  • Tylenol

Drug Interactions

No drug interactions were found for selected drugs: tizanidine, Tylenol.

This does not necessarily mean no interactions exist. Always consult your healthcare provider.

Drug and Food Interactions

Major
Tylenol + Food

The following applies to the ingredients: Acetaminophen (found in Tylenol)

GENERALLY AVOID: Chronic, excessive consumption of alcohol may increase the risk of acetaminophen-induced hepatotoxicity, which has included rare cases of fatal hepatitis and frank hepatic failure requiring liver transplantation. The proposed mechanism is induction of hepatic microsomal enzymes during chronic alcohol use, which may result in accelerated metabolism of acetaminophen and increased production of potentially hepatotoxic metabolites.

MANAGEMENT: In general, chronic alcoholics should avoid regular or excessive use of acetaminophen. Alternative analgesic/antipyretic therapy may be appropriate in patients who consume three or more alcoholic drinks per day. However, if acetaminophen is used, these patients should be cautioned not to exceed the recommended dosage (maximum 4 g/day in adults and children 12 years of age or older).

References

  1. Kaysen GA, Pond SM, Roper MH, Menke DJ, Marrama MA "Combined hepatic and renal injury in alcoholics during therapeutic use of acetaminophen." Arch Intern Med 145 (1985): 2019-23
  2. O'Dell JR, Zetterman RK, Burnett DA "Centrilobular hepatic fibrosis following acetaminophen-induced hepatic necrosis in an alcoholic." JAMA 255 (1986): 2636-7
  3. Seeff LB, Cuccherini BA, Zimmerman HJ, Adler E, Benjamin SB "Acetaminophen hepatotoxicity in alcoholics." Ann Intern Med 104 (1986): 399-404
  4. Thummel KE, Slattery JT, Nelson SD "Mechanism by which ethanol diminishes the hepatotoxicity of acetaminophen." J Pharmacol Exp Ther 245 (1988): 129-36
  5. McClain CJ, Kromhout JP, Peterson FJ, Holtzman JL "Potentiation of acetaminophen hepatotoxicity by alcohol." JAMA 244 (1980): 251-3
  6. Kartsonis A, Reddy KR, Schiff ER "Alcohol, acetaminophen, and hepatic necrosis." Ann Intern Med 105 (1986): 138-9
  7. Prescott LF, Critchley JA "Drug interactions affecting analgesic toxicity." Am J Med 75 (1983): 113-6
  8. "Product Information. Tylenol (acetaminophen)." McNeil Pharmaceutical PROD (2002):
  9. Whitcomb DC, Block GD "Association of acetaminopphen hepatotoxicity with fasting and ethanol use." JAMA 272 (1994): 1845-50
  10. Bonkovsky HL "Acetaminophen hepatotoxicity, fasting, and ethanol." JAMA 274 (1995): 301
  11. Nelson EB, Temple AR "Acetaminophen hepatotoxicity, fasting, and ethanol." JAMA 274 (1995): 301
  12. Zimmerman HJ, Maddrey WC "Acetaminophen (paracetamol) hepatotoxicity with regular intake of alcohol: analysis of instances of therapeutic misadventure." Hepatology 22 (1995): 767-73

Drug and Pregnancy Interactions

The following applies to the ingredients: Acetaminophen (found in Tylenol)

Benefit should outweigh risk

AU TGA pregnancy category: A
US FDA pregnancy category: Not Assigned

Risk Summary: A clear association of drug use and birth defects, miscarriage, or adverse maternal or fetal outcomes has not been shown with human use; animal studies have demonstrated adverse events at clinically relevant doses.

In pregnant rats receiving oral drug at doses up to 0.85 times maximum human daily dose (MHDD) during organogenesis, fetotoxicity and dose-related increases in bone variations (reduced ossification and rudimentary rib changes) were observed. Areas of necrosis in both the liver and kidney of pregnant rats and fetuses were observed when pregnant rats were given oral drug throughout gestation at doses 1.2 times the maximum human daily dose. Animal studies using the IV formulation have not been performed. In humans, this drug and its metabolites cross the placental barrier. Large cohort studies have not found an association between maternal use in the first trimester and either adverse pregnancy outcomes or congenital malformations. Some evidence of increased risk of neurodevelopmental disorders (e.g., attention deficit hyperactivity disorder [ADHD]), respiratory illness (e.g., asthma) and reproductive toxicity (e.g., androgen disruption) has been suggested in epidemiologic studies. However, extrapolating causation from pharmaco-epidemiological studies to humans is tricky considering various confounders and biases inherent in the study design. Associations seen in clinical cohort studies need clarification with randomized clinical trials (RCTs), which would be difficult to perform ethically in pregnant populations. The mechanism by which this drug or its metabolites affect neurological development, asthma, or endocrine/reproductive toxicity is poorly understood. It is important to factor in the risk of untreated febrile illness in mother and child when evaluating risks and benefits of using this drug. There are no controlled data in human pregnancy.

Epidemiologic data, including a population based case-control study from the National Birth Defects Prevention Study (n= 11,610) and data from 26,424 live singleton births have shown no increased risk of major birth defects in children with first trimester prenatal exposure. In 2015, the US Food and Drug Administration released results of their evaluation on published research studies looking at mothers who took this drug as either an over the counter or prescription product at any time during their pregnancy and the risk of attention deficit hyperactivity (ADHD) in their babies. They found all studies reviewed had potential limitations in their designs that prevented drawing reliable conclusions. In a prospective birth cohort study (Avon Longitudinal Study or Parents and Children [ALSPAC]) maternal drug exposure was assessed by questionnaire at 18 and 32 weeks, children were assessed at 61 months. Mothers were questioned about behavioral problems in their children at 7 years old; children's behavioral problems were assessed using the Strengths and Difficulties Questionnaire (SDQ). A number of confounders were evaluated although a limitation of the study was lack of information for drug use. The authors suggest there may be an association between drug use during pregnancy and behavioral problems in childhood that may be due to an intrauterine mechanism. Further studies are needed to test alternatives to a causal explanation.

According to published animal studies, this drug may cause reduced fertility in both males and females described as decreased testicular weights, reduced spermatogenesis, reduced fertility; and reduced implantation sites, respectively.

AU TGA pregnancy category A: Drugs which have been taken by a large number of pregnant women and women of childbearing age without any proven increase in the frequency of malformations or other direct or indirect harmful effects on the fetus having been observed.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

References

  1. Cerner Multum, Inc. "Australian Product Information." O 0
  2. U.S. Food and Drug Administration U.S. Food and Drug Administration U.S. Food and Drug Administration U.S. Food and Drug Administration "FDA Drug Safety Communication: FDA has reviewed possible risks of pain medicine use during pregnancy http://www.fda.gov/Drugs/DrugSafety/ucm429117.htm" (2015):
  3. "Product Information. Ofirmev (acetaminophen)." Cadence Pharmaceuticals Inc (2016):
  4. Stergaikoulie E, Thapar A, Davey Smith G "Association of acetaminophen use during pregnancy with behavioral problems in childhood: evidence against confounding." JAMA Pediatr 170 (2016): 964-70
  5. McCrae JC, Morrison EE, MacIntyre IM, Dear JW, Webb DJ "Long-term adverse effects of paracetamol - a review." Br J Clin Pharmacol 84 (2018): 2218-2230

The following applies to the ingredients: Tizanidine

Benefit should outweigh risk

US FDA pregnancy category: C

Teratogenicity was not shown in animal studies in rats and rabbits. At doses up to 8 times the maximum recommended human dose, increased gestation duration was observed in rats. Pre and prenatal and postnatal pup loss and developmental retardation occurred in rats and rabbits and post-implantation loss was increased in rabbits at doses of 1 mg/kg or more. There are no controlled studies in pregnant women.

US FDA pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

References

  1. "Product Information. Zanaflex (tizanidine)." Acorda Therapeutics PROD (2001):

Drug and Breastfeeding Interactions

The following applies to the ingredients: Tizanidine

Safety has not been established

Excreted into human milk: Unknown
Excreted into animal milk: Yes

Comments: If used, monitor infant for toxicity such as sedation, hypotension, and hallucinations.

As a lipid soluble drug, it might be expected to pass into breast milk.

References

  1. "Product Information. Zanaflex (tizanidine)." Acorda Therapeutics PROD (2001):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

The following applies to the ingredients: Acetaminophen (found in Tylenol)

Caution is recommended.

Excreted into human milk: Yes

Comments;
-This drug has been used without apparent harmful effects.
-This drug is considered compatible with breastfeeding by the American Academy of Pediatrics.

This drug is excreted into breast milk in very small amounts. Published reports reveal peak levels occur 1 to 2 hours after dosing and are undetectable after 12 hours. Reports have also shown infants ingesting 90 mL of breast milk every 3 hours would receive an average of 0.14% (range 0.04% to 0.23%) of the mother's dose; calculated to be a maximum maternal weight-adjusted dose of around 2%. Other studies have shown similar calculated maximal maternal weight adjusted doses (1.1% to 3.6%); these doses are about 0.5% of the lowest recommended infant dose of this drug. A single case of a maculopapular rash has been reported in a 2-month old nursing infant; the rash recurred on rechallenge.

References

  1. Committee on Drugs, 1992 to 1993 "The transfer of drugs and other chemicals into human milk." Pediatrics 93 (1994): 137-50
  2. Cerner Multum, Inc. "Australian Product Information." O 0
  3. United States National Library of Medicine "Toxnet. Toxicology Data Network. http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT" (2013):
  4. "Product Information. Ofirmev (acetaminophen)." Cadence Pharmaceuticals Inc (2016):

Therapeutic Duplication Warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

Switch to: Consumer Interactions

Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.

Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

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