Skip to main content

Drug Interactions between Genasan and Minizide

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

Edit list (add/remove drugs)

Interactions between your drugs

Moderate

prazosin aspirin

Applies to: Minizide (polythiazide / prazosin) and Genasan (aspirin / caffeine)

MONITOR: Nonsteroidal anti-inflammatory drugs (NSAIDs) may decrease the antihypertensive effect of prazosin. The proposed mechanism is NSAID-induced inhibition of prostaglandin synthesis. Data are available for indomethacin. A similar interaction is expected with other NSAIDs.

MANAGEMENT: The patient's blood pressure should be monitored during coadministration, and the dosage adjusted as necessary.

References

  1. Rubin P, Jackson G, Blaschke T "Studies on the clinical pharmacology of prazosin. II: The influence of indomethacin and of propranolol on the action and disposition of prazosin." Br J Clin Pharmacol 10 (1980): 33-9
  2. Radack KL, Deck CC, Bloomfield SS "Ibuprofen interferes with the efficacy of antihypertensive drugs: a randomized, double-blind, placebo-controlled trial of ibuprofen compared with acetaminophen." Ann Intern Med 107 (1987): 628-35

Switch to consumer interaction data

Moderate

prazosin polythiazide

Applies to: Minizide (polythiazide / prazosin) and Minizide (polythiazide / prazosin)

MONITOR: The hypotensive effects of thiazide diuretics and alpha-adrenergic blockers may be additive. Postural hypotension may occur.

MANAGEMENT: Hemodynamic responses should be monitored during coadministration, especially during the first few weeks of therapy. Patients should be advised to take the alpha-blocker at bedtime and to notify their physician if they experience dizziness or syncope while awake.

References

  1. Achari R, Laddu A "Terazosin: a new alpha adrenoceptor blocking drug." J Clin Pharmacol 32 (1992): 520-3
  2. Kuokkanen K, Mattila MJ "Demonstration of an additive antihypertensive effect of prazosin and polythiazide in out-patient." Curr Ther Res Clin Exp 17 (1975): 431-6
  3. Pool JL "Combination antihypertensive therapy with terazosin and other antihypertensive agents: results of clinical trials." Am Heart J 122 (1991): 926-31
  4. Cohen J "Long-term efficacy and safety of terazosin alone and in combination with other antihypertensive agents." Am Heart J 122 (1991): 919-25
  5. "Product Information. Xatral (alfuzosin)." Sanofi-Synthelabo Canada Inc (2002):
View all 5 references

Switch to consumer interaction data

Minor

aspirin caffeine

Applies to: Genasan (aspirin / caffeine) and Genasan (aspirin / caffeine)

One study has reported that coadministration of caffeine and aspirin lead to a 25% increase in the rate of appearance and 17% increase in maximum concentration of salicylate in the plasma. A significantly higher area under the plasma concentration time curve of salicylate was also reported when both drugs were administered together. The exact mechanism of this interaction has not been specified. Physicians and patients should be aware that coadministration of aspirin and caffeine may lead to higher salicylate levels faster.

References

  1. Yoovathaworn KC, Sriwatanakul K, Thithapandha A "Influence of caffeine on aspirin pharmacokinetics." Eur J Drug Metab Pharmacokinet 11 (1986): 71-6

Switch to consumer interaction data

Drug and food interactions

Moderate

prazosin food

Applies to: Minizide (polythiazide / prazosin)

GENERALLY AVOID: The concurrent use of ethanol and alpha-1 adrenergic blockers may cause increased hypotensive effects. Patients with aldehyde dehydrogenase deficiencies (primarily Asians) may be at a higher risk of this interaction. The mechanism has not been determined. Data exist for prazosin and other alpha adrenergic blockers are expected to interact also. In addition, any patients taking alpha adrenergic blockers may experience excessive orthostatic hypotension with ethanol ingestion, due to ethanol's unopposed vasodilatory effects in the presence of alpha adrenergic blockade.

MANAGEMENT: Patients who develop a flushing reaction after ethanol ingestion (indicates a possible aldehyde dehydrogenase deficiency) should be advised to avoid ethanol or limit their intake. All patients should be warned about the possibility of orthostatic hypotension with concurrent ethanol use.

References

  1. Kawano Y, Abe H, Kojima S, Takishita S, Omae T "Interaction of alcohol and an a1-blocker on ambulatory blood pressure in patients with essential hypertension." Am J Hypertens 13 (2000): 307-12
  2. "Product Information. Xatral (alfuzosin)." Sanofi-Synthelabo Canada Inc (2002):

Switch to consumer interaction data

Moderate

aspirin food

Applies to: Genasan (aspirin / caffeine)

GENERALLY AVOID: The concurrent use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) and ethanol may lead to gastrointestinal (GI) blood loss. The mechanism may be due to a combined local effect as well as inhibition of prostaglandins leading to decreased integrity of the GI lining.

MANAGEMENT: Patients should be counseled on this potential interaction and advised to refrain from alcohol consumption while taking aspirin or NSAIDs.

References

  1. "Product Information. Motrin (ibuprofen)." Pharmacia and Upjohn PROD (2002):

Switch to consumer interaction data

Moderate

polythiazide food

Applies to: Minizide (polythiazide / prazosin)

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 "Fluoxetine-associated potentiation of calcium-channel blockers." J Clin Psychopharmacol 11 (1991): 390-1
  2. Shook TL, Kirshenbaum JM, Hundley RF, Shorey JM, Lamas GA "Ethanol intoxication complicating intravenous nitroglycerin therapy." Ann Intern Med 101 (1984): 498-9
  3. Feder R "Bradycardia and syncope induced by fluoxetine." J Clin Psychiatry 52 (1991): 139
  4. Ellison JM, Milofsky JE, Ely E "Fluoxetine-induced bradycardia and syncope in two patients." J Clin Psychiatry 51 (1990): 385-6
  5. Rodriguez de la Torre B, Dreher J, Malevany I, et al. "Serum levels and cardiovascular effects of tricyclic antidepressants and selective serotonin reuptake inhibitors in depressed patients." Ther Drug Monit 23 (2001): 435-40
  6. Cerner Multum, Inc. "Australian Product Information." O 0
  7. Pacher P, Kecskemeti V "Cardiovascular side effects of new antidepressants and antipsychotics: new drugs, old concerns?" Curr Pharm Des 10 (2004): 2463-75
  8. Andrews C, Pinner G "Postural hypotension induced by paroxetine." BMJ 316 (1998): 595
View all 8 references

Switch to consumer interaction data

Minor

caffeine food

Applies to: Genasan (aspirin / caffeine)

The effect of grapefruit juice on the pharmacologic activity of caffeine is controversial. One report suggests that grapefruit juice increases the effect of caffeine. The proposed mechanism is inhibition of cytochrome P-450 metabolism of caffeine. However, a well-conducted pharmacokinetic/pharmacodynamic study did not demonstrate this effect. The clinical significance of this potential interaction is unknown.

References

  1. "Grapefruit juice interactions with drugs." Med Lett Drugs Ther 37 (1995): 73-4
  2. Maish WA, Hampton EM, Whitsett TL, Shepard JD, Lovallo WR "Influence of grapefruit juice on caffeine pharmacokinetics and pharmacodynamics." Pharmacotherapy 16 (1996): 1046-52

Switch to consumer interaction data

Minor

aspirin food

Applies to: Genasan (aspirin / caffeine)

One study has reported that coadministration of caffeine and aspirin lead to a 25% increase in the rate of appearance and 17% increase in maximum concentration of salicylate in the plasma. A significantly higher area under the plasma concentration time curve of salicylate was also reported when both drugs were administered together. The exact mechanism of this interaction has not been specified. Physicians and patients should be aware that coadministration of aspirin and caffeine may lead to higher salicylate levels faster.

References

  1. Yoovathaworn KC, Sriwatanakul K, Thithapandha A "Influence of caffeine on aspirin pharmacokinetics." Eur J Drug Metab Pharmacokinet 11 (1986): 71-6

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.

See also

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.

Medical Disclaimer