Skip to main content

Drug Interactions between hydrochlorothiazide / timolol and thioridazine

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

Edit list (add/remove drugs)

Interactions between your drugs

Moderate

timolol hydroCHLOROthiazide

Applies to: hydrochlorothiazide / timolol and hydrochlorothiazide / timolol

MONITOR: Although they are often combined in clinical practice, diuretics and beta-blockers may increase the risk of hyperglycemia and hypertriglyceridemia in some patients, especially in patients with diabetes or latent diabetes. In addition, the risk of QT interval prolongation and arrhythmias (e.g. torsades de pointes) due to sotalol may be increased by potassium-depleting diuretics.

MANAGEMENT: Monitoring of serum potassium levels, blood pressure, and blood glucose is recommended during coadministration. Patients should be advised to seek medical assistance if they experience dizziness, weakness, fainting, fast or irregular heartbeats, or loss of blood glucose control.

References

  1. Dornhorst A, Powell SH, Pensky J (1985) "Aggravation by propranolol of hyperglycaemic effect of hydrochlorothiazide in type II diabetics without alteration of insulin secretion." Lancet, 1, p. 123-6
  2. Roux A, Le Liboux A, Delhotal B, Gaillot J, Flouvat B (1983) "Pharmacokinetics in man of acebutolol and hydrochlorothiazide as single agents and in combination." Eur J Clin Pharmacol, 24, p. 801-6
  3. Dean S, Kendall MJ, Potter S, Thompson MH, Jackson DA (1985) "Nadolol in combination with indapamide and xipamide in resistant hypertensives." Eur J Clin Pharmacol, 28, p. 29-33
  4. (2002) "Product Information. Lozol (indapamide)." Rhone Poulenc Rorer
  5. Marcy TR, Ripley TL (2006) "Aldosterone antagonists in the treatment of heart failure." Am J Health Syst Pharm, 63, p. 49-58
View all 5 references

Switch to consumer interaction data

Moderate

timolol thioridazine

Applies to: hydrochlorothiazide / timolol and thioridazine

MONITOR: Phenothiazines, tricyclic antidepressants (TCAs), and some antipsychotic (neuroleptic) agents may potentiate the blood pressure lowering capabilities of other drugs with hypotensive effects due to their peripheral alpha-1 adrenergic blocking activity. Orthostatic hypotension and syncope associated with vasodilation may occur, particularly during initial dosing and/or parenteral administration of the phenothiazine, TCA, or neuroleptic. The severity of this interaction may be affected by the agent's affinity for the alpha-1 adrenoceptor. One in vitro study demonstrated an affinity for the alpha-1 adrenoceptor for some of these medications that was similar to, or greater than, those of alpha blocker medications used to treat hypertension. Examples of drugs evaluated in this study with a high affinity included amitriptyline, clomipramine, chlorpromazine, clozapine, doxepin, flupenthixol, lurasidone, nortriptyline, perphenazine, paliperidone, quetiapine, risperidone, sertindole, and ziprasidone. On the other hand, examples of those with lower affinities included aripiprazole, lofepramine, protriptyline, sulpiride, and amisulpride.

MANAGEMENT: Close clinical monitoring for development of hypotension is recommended if phenothiazines, tricyclic antidepressants (TCAs), or certain antipsychotic (neuroleptic) agents are used in patients receiving antihypertensive medications or vasodilators. A lower starting dosage and slower titration of the phenothiazine, TCA, or neuroleptic may be appropriate, especially in the elderly. It may also be advisable to consider using a phenothiazine, TCA, or neuroleptic medication with a lower affinity for the alpha-1 adrenoceptor when possible. Patients should be counseled to avoid rising abruptly from a sitting or recumbent position and to notify their healthcare provider if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia. Patients should also avoid driving or operating hazardous machinery until they know how the medications affect them.

References

  1. Fruncillo R, Gibbons W, Vlasses P, Ferguson R (1985) "Severe hypotension associated with concurrent clonidine and antipsychotic medication." Am J Psychiatry, 142, p. 274
  2. White WB (1986) "Hypotension with postural syncope secondary to the combination of chlorpromazine and captopril." Arch Intern Med, 146, p. 1833-4
  3. (2001) "Product Information. Clozaril (clozapine)." Novartis Pharmaceuticals
  4. (2001) "Product Information. Risperdal (risperidone)." Janssen Pharmaceuticals
  5. Aronowitz JS, Chakos MH, Safferman AZ, Lieberman JA (1994) "Syncope associated with the combination of clozapine and enalapril." J Clin Psychopharmacol, 14, p. 429-30
  6. Markowitz JS, Wells BG, Carson WH (1995) "Interactions between antipsychotic and antihypertensive drugs." Ann Pharmacother, 29, p. 603-9
  7. (2001) "Product Information. Zyprexa (olanzapine)." Lilly, Eli and Company
  8. (2001) "Product Information. Seroquel (quetiapine)." Astra-Zeneca Pharmaceuticals
  9. (2001) "Product Information. Geodon (ziprasidone)." Pfizer U.S. Pharmaceuticals
  10. (2002) "Product Information. Abilify (aripiprazole)." Bristol-Myers Squibb
  11. (2015) "Product Information. Rexulti (brexpiprazole)." Otsuka American Pharmaceuticals Inc
  12. Proudman RGW, Pupo AS, Baker JG (2020) "The affinity and selectivity of alpha-adrenoceptor antagonists, antidepressants, and antipsychotics for the human alpha1A, alpha1B, and alpha1D-adrenoceptors." Pharmacol Res Perspect, 8, e00602
View all 12 references

Switch to consumer interaction data

Moderate

hydroCHLOROthiazide thioridazine

Applies to: hydrochlorothiazide / timolol and thioridazine

MONITOR: Some neuroleptic agents may cause prolongation of the QT interval. While clinical data are lacking, the coadministration of other agents that can produce hypokalemia and/or hypomagnesemia (e.g., potassium-wasting diuretics, amphotericin B, cation exchange resins, stimulant laxatives) may result in elevated risk of ventricular arrhythmias, including ventricular tachycardia and torsade de pointes. In addition, neuroleptic agents may potentiate the hypotensive effect of diuretics secondary to their peripheral alpha-1 adrenergic blocking activity. Orthostatic hypotension and syncope associated with vasodilation may occur, particularly during the initial dose titration period of neuroleptic therapy.

MANAGEMENT: Caution is advised when neuroleptics must be used concomitantly with medications that can cause potassium and/or magnesium disturbances. Serum electrolytes should be monitored and any abnormalities corrected prior to initiating therapy with a neuroleptic. Close clinical monitoring for development of hypotension is recommended if neuroleptic agents are prescribed with a diuretic medication. Patients should be advised to notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia. A lower starting dosage and slower titration of the neuroleptic agent may be appropriate in patients receiving antihypertensive therapy, especially if they are elderly.

References

  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. Cerner Multum, Inc. "Australian Product Information."

Switch to consumer interaction data

Drug and food interactions

Moderate

timolol food

Applies to: hydrochlorothiazide / timolol

MONITOR: Many psychotherapeutic and CNS-active agents (e.g., anxiolytics, sedatives, hypnotics, antidepressants, antipsychotics, opioids, alcohol, muscle relaxants) exhibit hypotensive effects, especially during initiation of therapy and dose escalation. Coadministration with antihypertensives and other hypotensive agents, in particular vasodilators and alpha-blockers, may result in additive effects on blood pressure and orthostasis.

MANAGEMENT: Caution and close monitoring for development of hypotension is advised during coadministration of these agents. Some authorities recommend avoiding alcohol in patients receiving vasodilating antihypertensive drugs. Patients should be advised to avoid rising abruptly from a sitting or recumbent position and to notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia.

References

  1. Sternbach H (1991) "Fluoxetine-associated potentiation of calcium-channel blockers." J Clin Psychopharmacol, 11, p. 390-1
  2. Shook TL, Kirshenbaum JM, Hundley RF, Shorey JM, Lamas GA (1984) "Ethanol intoxication complicating intravenous nitroglycerin therapy." Ann Intern Med, 101, p. 498-9
  3. Feder R (1991) "Bradycardia and syncope induced by fluoxetine." J Clin Psychiatry, 52, p. 139
  4. Ellison JM, Milofsky JE, Ely E (1990) "Fluoxetine-induced bradycardia and syncope in two patients." J Clin Psychiatry, 51, p. 385-6
  5. Rodriguez de la Torre B, Dreher J, Malevany I, et al. (2001) "Serum levels and cardiovascular effects of tricyclic antidepressants and selective serotonin reuptake inhibitors in depressed patients." Ther Drug Monit, 23, p. 435-40
  6. Cerner Multum, Inc. "Australian Product Information."
  7. Pacher P, Kecskemeti V (2004) "Cardiovascular side effects of new antidepressants and antipsychotics: new drugs, old concerns?" Curr Pharm Des, 10, p. 2463-75
  8. Andrews C, Pinner G (1998) "Postural hypotension induced by paroxetine." BMJ, 316, p. 595
View all 8 references

Switch to consumer interaction data

Moderate

hydroCHLOROthiazide food

Applies to: hydrochlorothiazide / timolol

MONITOR: Many psychotherapeutic and CNS-active agents (e.g., anxiolytics, sedatives, hypnotics, antidepressants, antipsychotics, opioids, alcohol, muscle relaxants) exhibit hypotensive effects, especially during initiation of therapy and dose escalation. Coadministration with antihypertensives and other hypotensive agents, in particular vasodilators and alpha-blockers, may result in additive effects on blood pressure and orthostasis.

MANAGEMENT: Caution and close monitoring for development of hypotension is advised during coadministration of these agents. Some authorities recommend avoiding alcohol in patients receiving vasodilating antihypertensive drugs. Patients should be advised to avoid rising abruptly from a sitting or recumbent position and to notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia.

References

  1. Sternbach H (1991) "Fluoxetine-associated potentiation of calcium-channel blockers." J Clin Psychopharmacol, 11, p. 390-1
  2. Shook TL, Kirshenbaum JM, Hundley RF, Shorey JM, Lamas GA (1984) "Ethanol intoxication complicating intravenous nitroglycerin therapy." Ann Intern Med, 101, p. 498-9
  3. Feder R (1991) "Bradycardia and syncope induced by fluoxetine." J Clin Psychiatry, 52, p. 139
  4. Ellison JM, Milofsky JE, Ely E (1990) "Fluoxetine-induced bradycardia and syncope in two patients." J Clin Psychiatry, 51, p. 385-6
  5. Rodriguez de la Torre B, Dreher J, Malevany I, et al. (2001) "Serum levels and cardiovascular effects of tricyclic antidepressants and selective serotonin reuptake inhibitors in depressed patients." Ther Drug Monit, 23, p. 435-40
  6. Cerner Multum, Inc. "Australian Product Information."
  7. Pacher P, Kecskemeti V (2004) "Cardiovascular side effects of new antidepressants and antipsychotics: new drugs, old concerns?" Curr Pharm Des, 10, p. 2463-75
  8. Andrews C, Pinner G (1998) "Postural hypotension induced by paroxetine." BMJ, 316, p. 595
View all 8 references

Switch to consumer interaction data

Moderate

thioridazine food

Applies to: thioridazine

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

  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

Switch to consumer interaction data

Moderate

timolol food

Applies to: hydrochlorothiazide / timolol

ADJUST DOSING INTERVAL: Concurrent administration with calcium salts may decrease the oral bioavailability of atenolol and possibly other beta-blockers. The exact mechanism of interaction is unknown. In six healthy subjects, calcium 500 mg (as lactate, carbonate, and gluconate) reduced the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of atenolol (100 mg) by 51% and 32%, respectively. The elimination half-life increased by 44%. Twelve hours after the combination, beta-blocking activity (as indicated by inhibition of exercise tachycardia) was reduced compared to that with atenolol alone. However, during a 4-week treatment in six hypertensive patients, there was no difference in blood pressure values between treatments. The investigators suggest that prolongation of the elimination half-life induced by calcium coadministration may have led to atenolol cumulation during long-term dosing, which compensated for the reduced bioavailability.

MANAGEMENT: It may help to separate the administration times of beta-blockers and calcium products by at least 2 hours. Patients should be monitored for potentially diminished beta-blocking effects following the addition of calcium therapy.

References

  1. Kirch W, Schafer-Korting M, Axthelm T, Kohler H, Mutschler E (1981) "Interaction of atenolol with furosemide and calcium and aluminum salts." Clin Pharmacol Ther, 30, p. 429-35

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.


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.