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Drug Interactions between clozapine and viloxazine

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

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Interactions between your drugs

Major

cloZAPine viloxazine

Applies to: clozapine and viloxazine

GENERALLY AVOID: Coadministration with viloxazine may increase the plasma concentrations and risk of adverse effects, including agranulocytosis and QT prolongation, of clozapine. The proposed mechanism is viloxazine inhibition of the CYP450 3A4-mediated metabolism of clozapine. Inhibition of CYP450 2D6 and 3A4 may also contribute. In a pharmacokinetic study in 16 patients with schizophrenia receiving clozapine under steady-state conditions, coadministration of fluvoxamine (a potent CYP450 1A2 inhibitor) for 14 days, increased mean trough concentrations of clozapine and its metabolites 3-fold compared to baseline steady state concentrations. Concomitant administration of viloxazine and clozapine has not been studied, and therefore, the net effect of viloxazine on clozapine and its metabolites is unclear.

MANAGEMENT: Concomitant use of viloxazine with clozapine is not recommended; however, if coadministration is necessary, pharmacologic response and plasma clozapine concentrations should be monitored closely and the clozapine dosage adjusted as necessary. Patients should be advised to report symptoms such as somnolence, disorientation, slurred speech, seizures, uncontrolled movements, dizziness, irregular heartbeat, palpitations, fever, or hypersalivation to their doctor.

References (1)
  1. (2021) "Product Information. Qelbree (viloxazine)." Supernus Pharmaceuticals Inc

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

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.

See also

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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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