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Drug Interactions between amobarbital and chlorpromazine

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

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Interactions between your drugs

Moderate

chlorproMAZINE amobarbital

Applies to: chlorpromazine and amobarbital

MONITOR: Concomitant use of phenothiazines with barbiturates may reduce the plasma concentrations and therapeutic effects of both agents. The mechanism is unclear but may relate to metabolic induction of CYP450 hepatic enzymes. In addition, coadministration of phenothiazines and barbiturates may lead to a reduction in seizure threshold and additive central nervous system (CNS) and respiratory depressant effects.

MANAGEMENT: Administration of phenothiazines in patients receiving large doses of barbiturates is considered contraindicated by some authorities (US). If coadministration is required, caution as well as clinical and laboratory monitoring should be considered whenever either of these agents is added to or withdrawn from therapy. If chlorpromazine is coadministered with a barbiturate, the manufacturer of chlorpromazine recommends using 1/4 to 1/2 of the usual barbiturate dosage. Patients should be monitored for hypotension, loss of seizure control and the development of adverse effects including CNS and respiratory depression.

References (11)
  1. Harashima H, Sugiyama Y, Sawada Y, Shigenobu K, Kasuya Y, Iga T, Hanano M (1988) "Kinetic analysis of the positive inotropic action (PIA) of ouabain in isolated perfused rabbit heart. Slow onset of PIA and slow binding to Na+, K+-adenosine triphosphatase." J Pharmacobiodyn, 11, p. 533-40
  2. Dundee JW, Moore J (1961) "The effects of premedication with phenothiazine derivatives on the course of methohexitone anaesthesia." Br J Anaesth, 33, p. 382-96
  3. Forrest FM, Forrest IS, Serra MT (1970) "Modification of chlorpromazine metabolism by some other drugs frequently administered to psychiatric patients." Biol Psychiatry, 2, p. 53-8
  4. Linnoila M, Viukari M, Vaisanen K, Auvinen J (1980) "Effect of anticonvulsants on plasma haloperidol and thioridazine levels." Am J Psychiatry, 137, p. 819-21
  5. Ellenor GL, Musa MN, Beuthin FC (1978) "Phenobarbital-thioridazine interaction in man." Res Commun Chem Pathol Pharmacol, 21, p. 185-8
  6. Gay PE, Madsen JA (1983) "Interaction between phenobarbital and thioridazine." Neurology, 33, p. 1631-2
  7. Ellenor GL, Musa MN, Beuthin FC (1978) "Phenobarbital--thioridazine interaction in man." Res Commun Chem Pathol Pharmacol, 21, p. 185-8
  8. (2022) "Product Information. FluPHENAZine Decanoate (fluPHENAZine)." Mylan Institutional LLC
  9. (2019) "Product Information. Perphenazine (perphenazine)." Actavis Pharma, Inc.
  10. (2019) "Product Information. Trifluoperazine Hydrochloride (trifluoperazine)." Mylan Institutional (formerly UDL Laboratories)
  11. (2019) "Product Information. Thioridazine Hydrochloride (thioridazine)." Mylan Institutional (formerly UDL Laboratories)

Drug and food interactions

Major

amobarbital food

Applies to: amobarbital

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

chlorproMAZINE food

Applies to: chlorpromazine

GENERALLY AVOID: Concurrent use of ethanol and phenothiazines may result in additive CNS depression and psychomotor impairment. Also, ethanol may precipitate dystonic reactions in patients who are taking phenothiazines. The two drugs probably act on different sites in the brain, although the exact mechanism of the interaction is not known.

MANAGEMENT: Patients should be advised to avoid alcohol during phenothiazine therapy.

References (2)
  1. Lutz EG (1976) "Neuroleptic-induced akathisia and dystonia triggered by alcohol." JAMA, 236, p. 2422-3
  2. Freed E (1981) "Alcohol-triggered-neuroleptic-induced tremor, rigidity and dystonia." Med J Aust, 2, p. 44-5
Moderate

chlorproMAZINE food

Applies to: chlorpromazine

MONITOR: Smoking cessation may lead to elevated plasma concentrations and enhanced pharmacologic effects of drugs that are substrates of CYP450 1A2 (and possibly CYP450 1A1) and/or certain drugs with a narrow therapeutic index (e.g., flecainide, pentazocine). One proposed mechanism is related to the loss of CYP450 1A2 and 1A1 induction by polycyclic aromatic hydrocarbons in tobacco smoke; when smoking cessation agents are initiated and smoking stops, the metabolism of certain drugs may decrease leading to increased plasma concentrations. The mechanism by which smoking cessation affects narrow therapeutic index drugs that are not known substrates of CYP450 1A2 or 1A1 is unknown. The clinical significance of this interaction is unknown as clinical data are lacking.

MANAGEMENT: Until more information is available, caution is advisable if smoking cessation agents are used concomitantly with drugs that are substrates of CYP450 1A2 or 1A1 and/or those with a narrow therapeutic range. Patients receiving smoking cessation agents may require periodic dose adjustments and closer clinical and laboratory monitoring of medications that are substrates of CYP450 1A2 or 1A1.

References (4)
  1. (2024) "Product Information. Cytisine (cytisinicline)." Consilient Health Ltd
  2. jeong sh, Newcombe D, sheridan j, Tingle M (2015) "Pharmacokinetics of cytisine, an a4 b2 nicotinic receptor partial agonist, in healthy smokers following a single dose." Drug Test Anal, 7, p. 475-82
  3. Vaughan DP, Beckett AH, Robbie DS (1976) "The influence of smoking on the intersubject variation in pentazocine elimination." Br J Clin Pharmacol, 3, p. 279-83
  4. Zevin S, Benowitz NL (1999) "Drug interactions with tobacco smoking: an update" Clin Pharmacokinet, 36, p. 425-38

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.

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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.

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