Skip to main content

Drug Interactions between methadone and Pentothal

This report displays the potential drug interactions for the following 2 drugs:

Edit list (add/remove drugs)

Interactions between your drugs

Moderate

methadone thiopental

Applies to: methadone and Pentothal (thiopental)

ADJUST DOSE: Narcotic analgesics may reduce the dosage of barbiturate anesthetics needed to induce anesthesia by as much as 40%. Additionally, apnea is more common with this combination.

MANAGEMENT: Respiratory and cardiovascular status should be closely monitored, and anesthetic dosages titrated accordingly.

References

  1. DeLapa RJ "Influence of alphaprodine hydrochloride on intravenous barbiturate induction dosage." J Oral Surg 18 (1960): 163-8
  2. Dundee JW, Halliday NJ, McMurray TJ, Harper KW "Pretreatment with opioids: the effect on thiopentone induction requirements and on the onset of action of midazolam." Anaesthesia 41 (1986): 159-61
  3. Stambaugh JE, Hemphill DM, Wainer IW, Schwartz I "A potentially toxic drug interaction between pethidine (meperidine) and phenobarbitone." Lancet 1 (1977): 398-9
  4. Stambaugh JE, Wainer IW, Schwartz I "The effect of phenobarbital on the metabolism of meperidine in normal volunteers." J Clin Pharmacol 18 (1978): 482-90
View all 4 references

Switch to consumer interaction data

Drug and food interactions

Major

thiopental food

Applies to: Pentothal (thiopental)

GENERALLY AVOID: Concurrent acute use of barbiturates and ethanol may result in additive CNS effects, including impaired coordination, sedation, and death. Tolerance of these agents may occur with chronic use. The mechanism is related to inhibition of microsomal enzymes acutely and induction of hepatic microsomal enzymes chronically.

MANAGEMENT: The combination of ethanol and barbiturates should be avoided.

References

  1. Gupta RC, Kofoed J "Toxological statistics for barbiturates, other sedatives, and tranquilizers in Ontario: a 10-year survey." Can Med Assoc J 94 (1966): 863-5
  2. Misra PS, Lefevre A, Ishii H, Rubin E, Lieber CS "Increase of ethanol, meprobamate and pentobarbital metabolism after chronic ethanol administration in man and in rats." Am J Med 51 (1971): 346-51
  3. Saario I, Linnoila M "Effect of subacute treatment with hypnotics, alone or in combination with alcohol, on psychomotor skills related to driving." Acta Pharmacol Toxicol (Copenh) 38 (1976): 382-92
  4. Stead AH, Moffat AC "Quantification of the interaction between barbiturates and alcohol and interpretation of fatal blood concentrations." Hum Toxicol 2 (1983): 5-14
  5. Seixas FA "Drug/alcohol interactions: avert potential dangers." Geriatrics 34 (1979): 89-102
View all 5 references

Switch to consumer interaction data

Moderate

methadone food

Applies to: methadone

GENERALLY AVOID: Coadministration with grapefruit juice may increase the plasma concentrations of methadone. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. In 8 study subjects stabilized on methadone maintenance treatment, ingestion of regular strength grapefruit juice (200 mL one-half hour before and 200 mL simultaneously with the daily methadone dose) for five days resulted in an approximately 17% mean increase in methadone peak plasma concentration (Cmax) and systemic exposure (AUC) and a 14% mean decrease in apparent clearance for both the R(+) and S(-) enantiomers. Grapefruit juice did not affect the time to peak level (Tmax), terminal half-life, or apparent volume of distribution of methadone. No signs or symptoms of methadone toxicity or changes in intensity of withdrawal symptoms were reported in the study.

MANAGEMENT: Given the interindividual variability in the pharmacokinetics of methadone, a more significant interaction with grapefruit juice in certain patients cannot be ruled out. Patients treated with methadone should preferably avoid or limit the consumption of grapefruit juice, particularly during the induction of maintenance treatment.

References

  1. Iribarne C, Berthou F, Baird S, Dreano Y, Picart D, Bail JP, Beaune P, Menez JF "Involvement of cytochrome P450 3A4 enzyme in the N-demethylation of methadone in human liver microsomes." Chem Res Toxicol 9 (1996): 365-73
  2. Oda Y, Kharasch ED "Metabolism of methadone and levo-alpha-acetylmethadol (LAAM) by human intestinal cytochrome P450 3A4 (CYP3A4): potential contribution of intestinal metabolism to presystemic clearance and bioactivation." J Pharmacol Exp Ther 298 (2001): 1021-32
  3. Benmebarek M, Devaud C, Gex-Fabry M, et al. "Effects of grapefruit juice on the pharmacokinetics of the enantiomers of methadone." Clin Pharmacol Ther 76 (2004): 55-63
  4. Foster DJ, Somogyi AA, Bochner F "Methadone N-demethylation in human liver microsomes: lack of stereoselectivity and involvement of CYP3A4." Br J Clin Pharmacol 47 (1999): 403-12
View all 4 references

Switch to consumer interaction data

Moderate

methadone food

Applies to: methadone

GENERALLY AVOID: Ethanol may potentiate the central nervous system (CNS) depressant effects of opioid analgesics. Concomitant use may result in additive CNS depression and impairment of judgment, thinking, and psychomotor skills. In more severe cases, hypotension, respiratory depression, profound sedation, coma, or even death may occur.

MANAGEMENT: Concomitant use of opioid analgesics with ethanol should be avoided.

References

  1. Linnoila M, Hakkinen S "Effects of diazepam and codeine, alone and in combination with alcohol, on simulated driving." Clin Pharmacol Ther 15 (1974): 368-73
  2. Sturner WQ, Garriott JC "Deaths involving propoxyphene: a study of 41 cases over a two-year period." JAMA 223 (1973): 1125-30
  3. Girre C, Hirschhorn M, Bertaux L, et al. "Enhancement of propoxyphene bioavailability by ethanol: relation to psychomotor and cognitive function in healthy volunteers." Eur J Clin Pharmacol 41 (1991): 147-52
  4. Levine B, Saady J, Fierro M, Valentour J "A hydromorphone and ethanol fatality." J Forensic Sci 29 (1984): 655-9
  5. Sellers EM, Hamilton CA, Kaplan HL, Degani NC, Foltz RL "Pharmacokinetic interaction of propoxyphene with ethanol." Br J Clin Pharmacol 19 (1985): 398-401
  6. Carson DJ "Fatal dextropropoxyphene poisoning in Northern Ireland. Review of 30 cases." Lancet 1 (1977): 894-7
  7. Rosser WW "The interaction of propoxyphene with other drugs." Can Med Assoc J 122 (1980): 149-50
  8. Edwards C, Gard PR, Handley SL, Hunter M, Whittington RM "Distalgesic and ethanol-impaired function." Lancet 2 (1982): 384
  9. Kiplinger GF, Sokol G, Rodda BE "Effect of combined alcohol and propoxyphene on human performance." Arch Int Pharmacodyn Ther 212 (1974): 175-80
View all 9 references

Switch to consumer interaction data

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.

See also

Report options

Loading...
QR code containing a link to this page

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.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer