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Drug Interactions between clozapine and hydroxyzine

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

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Interactions between your drugs

Major

cloZAPine hydrOXYzine

Applies to: clozapine and hydroxyzine

MONITOR CLOSELY: Clozapine has the potential to prolong QT interval of the electrocardiogram. Theoretically, coadministration with other agents that can cause QT prolongation may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death. Clozapine treatment alone has been associated with ventricular arrhythmia, torsade de pointes, cardiac arrest, and sudden death. 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, hypocalcemia). In addition, the extent of drug-induced QT prolongation is dependent on the particular drug(s) involved and dosage(s) of the drug(s). Certain QT-prolonging agents (e.g., neuroleptics; phenothiazines; tricyclic antidepressants; some antihistamines, antispasmodics, and skeletal muscle relaxants) may also have additive parasympatholytic and central nervous system-depressant effects with clozapine. Excessive parasympatholytic effects can result in paralytic ileus, hyperthermia, mydriasis, blurred vision, tachycardia, urinary retention, psychosis, and seizures.

MANAGEMENT: Caution is recommended if clozapine is used in combination with other drugs that can prolong the QT interval. Serum electrolytes, including potassium, magnesium and calcium, should be measured at baseline and periodically during treatment, and any abnormalities corrected prior to initiating clozapine. Routine ECG assessment may detect QTc prolongation, but is not always effective in preventing arrhythmias. Clozapine treatment should be discontinued if the QTc interval exceeds 500 msec. 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. Additional precaution is required when using QT-prolonging agents with anticholinergic properties, particularly in the elderly and those with underlying organic brain disease. Patients should be advised to notify their physician if they experience potential symptoms of anticholinergic intoxication such as abdominal pain, fever, heat intolerance, blurred vision, confusion, and/or hallucinations. Dosage adjustments may be necessary if excessive adverse effects develop. Ambulatory patients should be counseled to avoid activities requiring mental alertness until they know how these agents affect them.

References (5)
  1. (2001) "Product Information. Clozaril (clozapine)." Novartis Pharmaceuticals
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  3. Canadian Pharmacists Association (2006) e-CPS. http://www.pharmacists.ca/function/Subscriptions/ecps.cfm?link=eCPS_quikLink
  4. Cerner Multum, Inc. "Australian Product Information."
  5. EMA. European Medicines Agency. European Union (2013) EMA - List of medicines under additional monitoring. http://www.ema.europa.eu/ema/index.jsp?curl=pages/regulation/document_listing/document_listing_000366.jsp&mid=WC0b01ac058067c852

Drug and food interactions

Moderate

cloZAPine food

Applies to: clozapine

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

hydrOXYzine food

Applies to: hydroxyzine

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

cloZAPine food

Applies to: clozapine

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
Minor

cloZAPine food

Applies to: clozapine

Caffeine may increase clozapine serum concentrations and exacerbate psychotic symptoms. The mechanism is unknown but may be related to competition for the same metabolic pathway. No specific intervention is necessary; however, if an interaction is suspected it is recommended that caffeine intake be avoided.

References (4)
  1. Carrillo JA, Jerling M, Bertilsson L (1995) "Interaction between caffeine and clozapine - comment." J Clin Psychopharmacol, 15, p. 376-7
  2. Odom-White A, de Leon J (1996) "Clozapine levels and caffeine." J Clin Psychiatry, 57, p. 175-6
  3. Vainer JL, Chouinard G (1994) "Interaction between caffeine and clozapine." J Clin Psychopharmacol, 14, p. 284
  4. Hagg S, Spiset O, Mjorndal T, Dalqvist R (2000) "Effect of caffeine on clozapine pharmacokinetics in healthy volunteers." Br J Clin Pharmacol, 49, p. 59-63

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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