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Drug Interactions between Diltiazem Hydrochloride CD and Pacaps

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

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Interactions between your drugs

Moderate

dilTIAZem butalbital

Applies to: Diltiazem Hydrochloride CD (diltiazem) and Pacaps (acetaminophen / butalbital / caffeine)

GENERALLY AVOID: Coadministration with inducers of CYP450 3A4 may significantly decrease the plasma concentrations of diltiazem, which is primarily metabolized by the isoenzyme. In 13 study subjects, administration of diltiazem (240 mg daily for 21 days) with the CYP450 3A4 inducer efavirenz (600 mg daily for 14 days) decreased diltiazem peak plasma concentration (Cmax), systemic exposure (AUC) and trough plasma concentration (Cmin) by a mean of 60%, 69% and 63%, respectively. Rifampin, a potent CYP450 3A4 inducer, has been reported to lower diltiazem plasma concentrations to undetectable levels.

MANAGEMENT: Use of diltiazem with rifampin or any known CYP450 3A4 inducer should be avoided when possible, and alternative therapy considered. Diltiazem dose adjustment should be guided by clinical response if concomitant use with a CYP450 3A4 inducer is necessary.

References

  1. Borcherding SM, Baciewicz AM, Self TH "Update on rifampin drug interactions." Arch Intern Med 152 (1992): 711-6
  2. Drda KD, Bastian TL, Self TH, et al. "Effects of debrisoquine hydroxylation phenotype and enzyme induction with rifampin on diltiazem pharmacokinetics and pharmacodynamics." Pharmacotherapy 11 (1991): 278
  3. "Product Information. Cardizem (diltiazem)." Hoechst Marion Roussel PROD (2002):
  4. Strayhorn VA, Baciewicz AM, Self TH "Update on rifampin drug interactions, III." Arch Intern Med 157 (1997): 2453-8
  5. "Product Information. Sustiva (efavirenz)." DuPont Pharmaceuticals PROD (2001):
View all 5 references

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Moderate

acetaminophen butalbital

Applies to: Pacaps (acetaminophen / butalbital / caffeine) and Pacaps (acetaminophen / butalbital / caffeine)

MONITOR: Barbiturates may increase the hepatotoxic potential of acetaminophen and decrease its therapeutic effects. The mechanism may be related to accelerated CYP450 metabolism of acetaminophen with consequent increase in hepatotoxic metabolites. This interaction is of greatest concern in cases of acetaminophen overdose.

MANAGEMENT: Monitoring for altered efficacy and safety is recommended. Prolonged use or high doses of acetaminophen should be avoided by patients on barbiturate therapy.

References

  1. Pirotte JH "Apparent potentiation by phenobarbital of hepatotoxicity from small doses of acetaminophen." Ann Intern Med 101 (1984): 403
  2. Douidar SM, Ahmed AE "A novel mechanism for the enhancement of acetaminophen hepatotoxicity by phenobarbital." J Pharmacol Exp Ther 240 (1987): 578-83
  3. Wright N, Prescott LF "Potentiation by previous drug therapy of hepatotoxicity following paracetamol overdose." Scott Med J 18 (1973): 56-8
  4. Bock KW, Wiltfang J, Blume R, Ullrich D, Bircher J "Paracetamol as a test drug to determine glucuronide formation in man: effects of inducers and of smoking." Eur J Clin Pharmacol 31 (1987): 677-83
View all 4 references

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Drug and food interactions

Major

acetaminophen food

Applies to: Pacaps (acetaminophen / butalbital / caffeine)

GENERALLY AVOID: Chronic, excessive consumption of alcohol may increase the risk of acetaminophen-induced hepatotoxicity, which has included rare cases of fatal hepatitis and frank hepatic failure requiring liver transplantation. The proposed mechanism is induction of hepatic microsomal enzymes during chronic alcohol use, which may result in accelerated metabolism of acetaminophen and increased production of potentially hepatotoxic metabolites.

MANAGEMENT: In general, chronic alcoholics should avoid regular or excessive use of acetaminophen. Alternative analgesic/antipyretic therapy may be appropriate in patients who consume three or more alcoholic drinks per day. However, if acetaminophen is used, these patients should be cautioned not to exceed the recommended dosage (maximum 4 g/day in adults and children 12 years of age or older).

References

  1. Kaysen GA, Pond SM, Roper MH, Menke DJ, Marrama MA "Combined hepatic and renal injury in alcoholics during therapeutic use of acetaminophen." Arch Intern Med 145 (1985): 2019-23
  2. O'Dell JR, Zetterman RK, Burnett DA "Centrilobular hepatic fibrosis following acetaminophen-induced hepatic necrosis in an alcoholic." JAMA 255 (1986): 2636-7
  3. Seeff LB, Cuccherini BA, Zimmerman HJ, Adler E, Benjamin SB "Acetaminophen hepatotoxicity in alcoholics." Ann Intern Med 104 (1986): 399-404
  4. Thummel KE, Slattery JT, Nelson SD "Mechanism by which ethanol diminishes the hepatotoxicity of acetaminophen." J Pharmacol Exp Ther 245 (1988): 129-36
  5. McClain CJ, Kromhout JP, Peterson FJ, Holtzman JL "Potentiation of acetaminophen hepatotoxicity by alcohol." JAMA 244 (1980): 251-3
  6. Kartsonis A, Reddy KR, Schiff ER "Alcohol, acetaminophen, and hepatic necrosis." Ann Intern Med 105 (1986): 138-9
  7. Prescott LF, Critchley JA "Drug interactions affecting analgesic toxicity." Am J Med 75 (1983): 113-6
  8. "Product Information. Tylenol (acetaminophen)." McNeil Pharmaceutical PROD (2002):
  9. Whitcomb DC, Block GD "Association of acetaminopphen hepatotoxicity with fasting and ethanol use." JAMA 272 (1994): 1845-50
  10. Bonkovsky HL "Acetaminophen hepatotoxicity, fasting, and ethanol." JAMA 274 (1995): 301
  11. Nelson EB, Temple AR "Acetaminophen hepatotoxicity, fasting, and ethanol." JAMA 274 (1995): 301
  12. Zimmerman HJ, Maddrey WC "Acetaminophen (paracetamol) hepatotoxicity with regular intake of alcohol: analysis of instances of therapeutic misadventure." Hepatology 22 (1995): 767-73
View all 12 references

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Major

butalbital food

Applies to: Pacaps (acetaminophen / butalbital / caffeine)

GENERALLY AVOID: Concurrent acute use of barbiturates and ethanol may result in additive CNS effects, including impaired coordination, sedation, and death. Tolerance of these agents may occur with chronic use. The mechanism is related to inhibition of microsomal enzymes acutely and induction of hepatic microsomal enzymes chronically.

MANAGEMENT: The combination of ethanol and barbiturates should be avoided.

References

  1. Gupta RC, Kofoed J "Toxological statistics for barbiturates, other sedatives, and tranquilizers in Ontario: a 10-year survey." Can Med Assoc J 94 (1966): 863-5
  2. Misra PS, Lefevre A, Ishii H, Rubin E, Lieber CS "Increase of ethanol, meprobamate and pentobarbital metabolism after chronic ethanol administration in man and in rats." Am J Med 51 (1971): 346-51
  3. Saario I, Linnoila M "Effect of subacute treatment with hypnotics, alone or in combination with alcohol, on psychomotor skills related to driving." Acta Pharmacol Toxicol (Copenh) 38 (1976): 382-92
  4. Stead AH, Moffat AC "Quantification of the interaction between barbiturates and alcohol and interpretation of fatal blood concentrations." Hum Toxicol 2 (1983): 5-14
  5. Seixas FA "Drug/alcohol interactions: avert potential dangers." Geriatrics 34 (1979): 89-102
View all 5 references

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Moderate

dilTIAZem food

Applies to: Diltiazem Hydrochloride CD (diltiazem)

MONITOR: Like many CNS-active agents, alcohol can exhibit hypotensive effects. Coadministration with antihypertensive agents including diltiazem may result in additive effects on blood pressure and orthostasis.

MONITOR: Grapefruit juice may increase the plasma concentrations of orally administered diltiazem in some patients. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. In a study of ten healthy male volunteers, administration of a single 120 mg oral dose of immediate-release diltiazem in combination with 250 mL of grapefruit juice increased the diltiazem peak plasma concentration (Cmax) and systemic exposure (AUC) by an average of 22% and 20%, respectively, compared to administration with water. The time to reach Cmax (Tmax) and the terminal half-life were not affected, and no statistically significant differences in blood pressure and heart rate were observed during administration with grapefruit juice relative to water. In a different study, repeated administration of 200 mL of grapefruit juice at 0, 2, 4, 8 and 12 hours had no significant effect on the Cmax or AUC of a single 120 mg oral dose of diltiazem, but increased its half-life from 4.1 to 5.1 hours. The ratios for the N-demethyl and deacetyl metabolites to diltiazem were also not affected by grapefruit juice. However, because pharmacokinetic interactions involving grapefruit juice are often subject to a high degree of interpatient variability, the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: Patients should be advised that alcohol may potentiate the hypotensive effects of diltiazem, especially during the initiation of therapy and following a dosage increase. Caution should be exercised when rising from a sitting or recumbent position, and patients should notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia. Patients who regularly consume grapefruit or grapefruit juice should be monitored for increased adverse effects of diltiazem such as such as headache, irregular heartbeat, edema, unexplained weight gain, and chest pain. Grapefruit and grapefruit juice should be avoided if an interaction is suspected.

References

  1. Bailey DG, Arnold JMO, Spence JD "Grapefruit juice and drugs - how significant is the interaction." Clin Pharmacokinet 26 (1994): 91-8
  2. Sigusch H, Henschel L, Kraul H, Merkel U, Hoffmann A "Lack of effect of grapefruit juice on diltiazem bioavailability in normal subjects." Pharmazie 49 (1994): 675-9
  3. Bailey DG, Malcolm J, Arnold O, Spence JD "Grapefruit juice-drug interactions." Br J Clin Pharmacol 46 (1998): 101-10
  4. Christensen H, Asberg A, Holmboe AB, Berg KJ "Coadministration of grapefruit juice increases systemic exposure of diltiazem in healthy volunteers." Eur J Clin Pharmacol 58 (2002): 515-520
  5. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
View all 5 references

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Moderate

dilTIAZem food

Applies to: Diltiazem Hydrochloride CD (diltiazem)

MONITOR: Calcium-containing products may decrease the effectiveness of calcium channel blockers by saturating calcium channels with calcium. Calcium chloride has been used to manage acute severe verapamil toxicity.

MANAGEMENT: Management consists of monitoring the effectiveness of calcium channel blocker therapy during coadministration with calcium products.

References

  1. Henry M, Kay MM, Viccellio P "Cardiogenic shock associated with calcium-channel and beta blockers: reversal with intravenous calcium chloride." Am J Emerg Med 3 (1985): 334-6
  2. Moller IW "Cardiac arrest following intravenous verapamil combined with halothane anaesthesia." Br J Anaesth 59 (1987): 522-6
  3. Oszko MA, Klutman NE "Use of calcium salts during cardiopulmonary resuscitation for reversing verapamil-associated hypotension." Clin Pharm 6 (1987): 448-9
  4. Schoen MD, Parker RB, Hoon TJ, et al. "Evaluation of the pharmacokinetics and electrocardiographic effects of intravenous verapamil with intravenous calcium chloride pretreatment in normal subjects." Am J Cardiol 67 (1991): 300-4
  5. O'Quinn SV, Wohns DH, Clarke S, Koch G, Patterson JH, Adams KF "Influence of calcium on the hemodynamic and anti-ischemic effects of nifedipine observed during treadmill exercise testing." Pharmacotherapy 10 (1990): 247
  6. Woie L, Storstein L "Successful treatment of suicidal verapamil poisoning with calcium gluconate." Eur Heart J 2 (1981): 239-42
  7. Morris DL, Goldschlager N "Calcium infusion for reversal of adverse effects of intravenous verapamil." JAMA 249 (1983): 3212-3
  8. Guadagnino V, Greengart A, Hollander G, Solar M, Shani J, Lichstein E "Treatment of severe left ventricular dysfunction with calcium chloride in patients receiving verapamil." J Clin Pharmacol 27 (1987): 407-9
  9. Luscher TF, Noll G, Sturmer T, Huser B, Wenk M "Calcium gluconate in severe verapamil intoxication." N Engl J Med 330 (1994): 718-20
  10. Bar-Or D, Gasiel Y "Calcium and calciferol antagonise effect of verapamil in atrial fibrillation." Br Med J (Clin Res Ed) 282 (1981): 1585-6
  11. Lipman J, Jardine I, Roos C, Dreosti L "Intravenous calcium chloride as an antidote to verapamil-induced hypotension." Intensive Care Med 8 (1982): 55-7
  12. McMillan R "Management of acute severe verapamil intoxication." J Emerg Med 6 (1988): 193-6
  13. Perkins CM "Serious verapamil poisoning: treatment with intravenous calcium gluconate." Br Med J 2 (1978): 1127
  14. Moroni F, Mannaioni PF, Dolara A, Ciaccheri M "Calcium gluconate and hypertonic sodium chloride in a case of massive verapamil poisoning." Clin Toxicol 17 (1980): 395-400
View all 14 references

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Minor

caffeine food

Applies to: Pacaps (acetaminophen / butalbital / 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

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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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