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Acetaminophen / dichloralphenazone / isometheptene mucate Pregnancy and Breastfeeding Warnings

Brand names: Alidrin, Amidrine, Diacetazone, Duradrin, Epidrin, IDA, Iso-Acetazone, Isocom, LarkaDrin, Midchlor, Midrin, Migquin, Migragesic IDA, Migrapap, Migratine, Migrazone, Migrex, Migrin-A, Mitride, Nodolor

Acetaminophen / dichloralphenazone / isometheptene mucate Pregnancy Warnings

Acetaminophen has not been formally assigned to a pregnancy category by the FDA. It is routinely used for short-term pain relief and fever in all stages of pregnancy. Acetaminophen is believed to be safe in pregnancy when used intermittently for short durations.

Dichloralphenazone has not been formally assigned to a pregnancy category by the FDA. Animal studies have not been reported. There are no controlled data in human pregnancy.

Isometheptene has not been formally assigned to a pregnancy category by the FDA. Animal studies have not been reported. There are no controlled data in human pregnancy.

Acetaminophen/dichloralphenazone/isometheptene should only be given during pregnancy when need has been clearly established.

Two cases of acetaminophen overdose in late pregnancy have been reported. In both cases neither the neonate nor the mother suffered hepatic toxicity.

Investigations have revealed conflicting results with regards to the pharmacokinetic disposition of acetaminophen in pregnant women. One study has suggested that the oral clearance of acetaminophen is 58% higher and the elimination half-life is 28% longer in pregnant women compared to non-pregnant women. Another study has suggested that the elimination half-life is not different in patients who are pregnant. That study also suggested that the volume of distribution of acetaminophen may be higher in pregnant women.

One study has suggested that acetaminophen in typical oral doses may result in a reduced production of prostacyclin in pregnant women. That study also suggested that acetaminophen does not affect thromboxane production.

See references

Acetaminophen / dichloralphenazone / isometheptene mucate Breastfeeding Warnings

Acetaminophen is excreted into human milk in small concentrations. One case of a rash has been reported in a nursing infant. Acetaminophen is considered compatible with breast-feeding by the American Academy of Pediatrics.

Dichloralphenazone is a prodrug composed of phenazone and chloral hydrate. Both phenazone and the active metabolite of chloral hydrate, trichloroethanol, are excreted into human milk. Milk concentrations of trichoroethanol have been reported at 60% to 80% of maternal serum levels. The only effect reported in the infant was mild morning drowsiness.

There are no data on the excretion of isometheptene into human milk.

One small study on acetaminophen has reported that following a 1000 mg dose of acetaminophen to nursing mothers, nursing infants receive less than 1.85% of the weight-adjusted maternal oral dose.

See references

References for pregnancy information

  1. Rayburn W, Shukla U, Stetson P, Piehl E (1986) "Acetaminophen pharmacokinetics: comparison between pregnant and nonpregnant women." Am J Obstet Gynecol, 155, p. 1353-6
  2. Byer AJ, Traylor TR, Semmer JR (1982) "Acetaminophen overdose in the third trimester of pregnancy." JAMA, 247, p. 3114-5
  3. Roberts I, Robinson MJ, Mughal MZ, Ratcliffe JG, Prescott LF (1984) "Paracetamol metabolites in the neonate following maternal overdose." Br J Clin Pharmacol, 18, p. 201-6
  4. Miners JO, Robson RA, Birkett DJ (1986) "Paracetamol metabolism in pregnancy." Br J Clin Pharmacol, 22, p. 359-62
  5. Galinsky RE, Levy G (1984) "Absorption and metabolism of acetaminophen shortly before parturition." Drug Intell Clin Pharm, 18, p. 977-9
  6. Levy G, Garrettson LK, Soda DM (1975) "Evidence of placental transfer of acetaminophen." Pediatrics, 55, p. 895
  7. Rudolph AM (1981) "Effects of aspirin and acetaminophen in pregnancy and in the newborn." Arch Intern Med, 141, p. 358-63
  8. Heinonen O, Shapiro S; Kaufman DW ed., Slone D (1977) "Birth Defects and Drugs in Pregnancy." Littleton, MA: Publishing Sciences Group, Inc., p. 297
  9. O'Brien WF, Krammer J, O'Leary TD, Mastrogiannis DS (1993) "The effect of acetaminophen on prostacyclin production in pregnant women." Am J Obstet Gynecol, 168, p. 1164-9
  10. Beaulac-Baillargeon L, Rocheleau S (1994) "Paracetamol pharmacokinetics during the first trimester of human pregnancy." Eur J Clin Pharmacol, 46, p. 451-4
  11. (2022) "Product Information. Midrin (APAP/dichloralphenazone/isometheptene)." Carnrick Laboratories Inc
  12. Briggs GG, Freeman RK, Yaffe SJ.. (1998) "Drugs in Pregnancy and Lactation." Baltimore, MD: Williams & Wilkins
  13. McColl JD, Globus M, Robinson S (1965) "Effect of some therapeutic agents on the developing rat fetus." Toxicol Appl Pharmacol, 7, p. 409-17
  14. Lewis PJ, Friedman LA (1979) "Prophylaxis of neonatal jaundice with maternal antipyrine treatment." Lancet, 1, p. 300-2

References for breastfeeding information

  1. Findlay JW, DeAngelis RL, Kearney MF, et al. (1981) "Analgesic drugs in breast milk and plasma." Clin Pharmacol Ther, 29, p. 625-33
  2. Notarianni LJ, Oldham HG, Bennett PN (1987) "Passage of paracetamol into breast milk and its subsequent metabolism by the neonate." Br J Clin Pharmacol, 24, p. 63-7
  3. Roberts RJ, Blumer JL, Gorman RL, et al. (1989) "American Academy of Pediatrics Committee on Drugs: Transfer of drugs and other chemicals into human milk." Pediatrics, 84, p. 924-36
  4. Matheson I, Lunde PK, Notarianni L (1985) "Infant rash caused by paracetamol in breast milk." Pediatrics, 76, p. 651-2
  5. Heinonen O, Shapiro S; Kaufman DW ed., Slone D (1977) "Birth Defects and Drugs in Pregnancy." Littleton, MA: Publishing Sciences Group, Inc., p. 297
  6. Committee on Drugs, 1992 to 1993 (1994) "The transfer of drugs and other chemicals into human milk." Pediatrics, 93, p. 137-50
  7. (2022) "Product Information. Midrin (APAP/dichloralphenazone/isometheptene)." Carnrick Laboratories Inc
  8. Briggs GG, Freeman RK, Yaffe SJ.. (1998) "Drugs in Pregnancy and Lactation." Baltimore, MD: Williams & Wilkins
  9. McColl JD, Globus M, Robinson S (1965) "Effect of some therapeutic agents on the developing rat fetus." Toxicol Appl Pharmacol, 7, p. 409-17
  10. Lewis PJ, Friedman LA (1979) "Prophylaxis of neonatal jaundice with maternal antipyrine treatment." Lancet, 1, p. 300-2
  11. Lacey JH (1971) "Dichloralphenazone and breast milk." Br Med J, 4, p. 684

Further information

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