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Drug Interactions between Effexor and haloperidol

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

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Interactions between your drugs

Major

haloperidol venlafaxine

Applies to: haloperidol and Effexor (venlafaxine)

MONITOR CLOSELY: Haloperidol can cause dose-related prolongation of the QT interval. Theoretically, coadministration with other agents that can prolong the QT interval such as venlafaxine may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death. Haloperidol treatment alone has been associated with a number of reported cases of torsade de pointes and sudden death. The majority of cases involved intravenous administration or use of higher than recommended dosages. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia). In addition, the extent of drug-induced QT prolongation is dependent on the particular drugs involved and dosages of the drugs. Pharmacokinetically, venlafaxine has been shown to increase haloperidol serum concentrations by decreasing its clearance. In 24 healthy subjects, venlafaxine given at 75 mg every 12 hours to steady state reduced the clearance of a single oral 2 mg dose of haloperidol by 42%, resulting in increases of 88% and 70% in haloperidol peak plasma concentration (Cmax) and systemic exposure (AUC), respectively, with no change in elimination half-life. The mechanism of interaction is unknown.

MANAGEMENT: Caution is recommended if haloperidol is used in combination with other drugs that can prolong the QT interval, particularly when administered intravenously or at higher than recommended dosages. Dose adjustments for haloperidol may be required when used with venlafaxine due to potentially increased haloperidol levels. Patients should be monitored for increased adverse effects such as tachycardia, hypotension, extrapyramidal reactions (e.g., Parkinson-like symptoms, akathisia, dystonia), drowsiness, depression, and seizures. Patients should be advised to seek prompt medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitation, irregular heart rhythm, shortness of breath, or syncope.

References (7)
  1. Huyse F, van Schijndel RS (1988) "Haloperidol and cardiac arrest." Lancet, 2, p. 568-9
  2. (2002) "Product Information. Haldol (haloperidol)." McNeil Pharmaceutical
  3. Wilt JL, Minnema AM, Johnson RF, Rosenblum AM (1993) "Torsade de pointes associated with the use of intravenous haloperidol." Ann Intern Med, 119, p. 391-4
  4. Metzger E, Friedman R (1993) "Prolongation of the corrected QT and torsades de pointes cardiac arrhythmia associated with intravenous haloperidol in the medically ill." J Clin Psychopharmacol, 13, p. 128-32
  5. O'Brien JM, Rockwood RP, Suh KI (1999) "Haloperidol-induced torsade de pointes." Ann Pharmacother, 33, p. 1046-9
  6. Hatta K, Takahashi T, Nakamura H, Yamashiro H, Asukai N, Matsuzaki I, Yonezawa Y (2001) "The association between intravenous haloperidol and prolonged QT interval." J Clin Psychopharmacol, 21, p. 257-61
  7. (2002) "Product Information. Effexor XR (venlafaxine)." Wyeth-Ayerst Laboratories

Drug and food interactions

Moderate

haloperidol food

Applies to: haloperidol

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

References (4)
  1. Warrington SJ, Ankier SI, Turner P (1986) "Evaluation of possible interactions between ethanol and trazodone or amitriptyline." Neuropsychobiology, 15, p. 31-7
  2. Gilman AG, eds., Nies AS, Rall TW, Taylor P (1990) "Goodman and Gilman's the Pharmacological Basis of Therapeutics." New York, NY: Pergamon Press Inc.
  3. (2012) "Product Information. Fycompa (perampanel)." Eisai Inc
  4. (2015) "Product Information. Rexulti (brexpiprazole)." Otsuka American Pharmaceuticals Inc
Moderate

venlafaxine food

Applies to: Effexor (venlafaxine)

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

References (4)
  1. Warrington SJ, Ankier SI, Turner P (1986) "Evaluation of possible interactions between ethanol and trazodone or amitriptyline." Neuropsychobiology, 15, p. 31-7
  2. Gilman AG, eds., Nies AS, Rall TW, Taylor P (1990) "Goodman and Gilman's the Pharmacological Basis of Therapeutics." New York, NY: Pergamon Press Inc.
  3. (2012) "Product Information. Fycompa (perampanel)." Eisai Inc
  4. (2015) "Product Information. Rexulti (brexpiprazole)." Otsuka American Pharmaceuticals Inc
Moderate

haloperidol food

Applies to: haloperidol

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

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