Monday, May 17, 2010

Acetaminophen, caffeine, and dihydrocodeineAcetaminophen, caffeine, and dihydrocodeine

MEDICATION SAFETY ISSUES
Sound-alike/look-alike issues:
Panlor® DC may be confused with Pamelor®

High alert medication: The Institute for Safe Medication Practices (ISMP) includes this medication among its list of drug classes which have a heightened risk of causing significant patient harm when used in error.

Duplicate therapy issues: This product contains acetaminophen, which may be a component of other combination products. Do not exceed the maximum recommended daily dose of acetaminophen.

U.S. BRAND NAMES — Panlor® DC; Panlor® SS; Trezix®; ZerLor™

PHARMACOLOGIC CATEGORY
Analgesic Combination (Opioid)

DOSING: ADULTS — Relief of pain: Oral:

Panlor® DC, Trezix®: 2 capsules every 4 hours as needed; adjust dose based on severity of pain (maximum dose: 10 capsules/24 hours)

Panlor® SS, ZerLor™ : 1 tablet every 4 hours as needed; adjust dose based on severity of pain (maximum dose: 5 tablets/24 hours)

DOSING: ELDERLY — Refer to adult dosing.

DOSAGE FORMS — Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Capsule:
Panlor® DC: Acetaminophen 356.4 mg, caffeine 30 mg, and dihydrocodeine bitartrate 16 mg
Trezix®: Acetaminophen 356.4 mg, caffeine 30 mg, and dihydrocodeine bitartrate 16 mg

Tablet:
Panlor® SS, ZerLor™ : Acetaminophen 712.8 mg, caffeine 60 mg, and dihydrocodeine bitartrate 32 mg

DOSAGE FORMS: CONCISE
Capsule:
Panlor® DC, Trezix®: Acetaminophen 356.4 mg, caffeine 30 mg, and dihydrocodeine 16 mg

Tablet:
Panlor® SS, ZerLor™ : Acetaminophen 712.8 mg, caffeine 60 mg, and dihydrocodeine 32 mg

GENERIC EQUIVALENT AVAILABLE — Yes: Tablet

USE — Relief of moderate to moderately-severe pain

ADVERSE REACTIONS SIGNIFICANT — Frequency not defined. Most common reactions with this combination include:

Central nervous system: Dizziness, drowsiness, lightheadedness, sedation

Dermatologic: Pruritus, skin reactions

Gastrointestinal: Constipation, nausea, vomiting

CONTRAINDICATIONS — Hypersensitivity to acetaminophen, caffeine, dihydrocodeine, codeine, or any component of the formulation; significant respiratory depression (in unmonitored settings); acute or severe bronchial asthma; hypercapnia; paralytic ileus

WARNINGS / PRECAUTIONS
Concerns related to adverse effects: CNS depression: May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving). Hepatotoxicity: Acetaminophen may cause severe hepatic toxicity on acute overdose; in addition, chronic daily dosing in adults has resulted in liver damage in some patients. Phenanthrene hypersensitivity: Use with caution in patients with hypersensitivity reactions to other phenanthrene-derivative opioid agonists (hydrocodone, hydromorphone, levorphanol, oxycodone, oxymorphone).

Disease-related concerns: Adrenal insufficiency: Use with caution in patients with adrenal insufficiency, including Addison's disease. CNS depression/coma: Use with caution in patients with CNS depression or coma. Drug abuse: Use with caution in patients with a history of drug abuse or acute alcoholism; potential for drug dependency exists. Tolerance, psychological and physical dependence may occur with prolonged use. Ethanol use: Use with caution in patients with alcoholic liver disease; consuming ≥ 3 alcoholic drinks/day may increase the risk of liver damage. G6PD deficiency: Use with caution in patients with known G6PD deficiency. Head trauma: Use with extreme caution in patients with head injury, intracranial lesions, or elevated intracranial pressure; exaggerated elevation of ICP may occur. Hepatic impairment: Use with caution in patients with severe hepatic impairment. Hypotension: Use with caution in patients with hypotension. Prostatic hyperplasia/urinary stricture: Use with caution in patients with prostatic hyperplasia and/or urinary stricture. Renal impairment: Use with caution in patients with severe renal impairment. Respiratory disease: Use with caution in patients with respiratory diseases including asthma, emphysema, and/or COPD. Seizure disorder: Use with caution in patients with a history of seizure disorder. Thyroid dysfunction: Use with caution in patients with thyroid dysfunction.

Concurrent drug therapy issues: MAO inhibitors: Use with caution with concurrent use of MAO inhibitors.

Special populations: Debilitated patients: Use with caution in debilitated patients; there is a greater potential for critical respiratory depression, even at therapeutic dosages. Elderly: Use with caution in the elderly; may be more sensitive to adverse effects. Pediatrics: Safety and efficacy have not been established in children.

Other warnings/precautions: Caffeine: May cause CNS and cardiovascular stimulation, as well as GI irritation in high doses. Use with caution in patients with a history of peptic ulcer or GERD; avoid in patients with symptomatic cardiac arrhythmias. Dosage limit: Limit total acetaminophen dose to <4 g/day.

RESTRICTIONS — C-III

METABOLISM / TRANSPORT EFFECTS
Acetaminophen: Substrate (minor) of CYP1A2, 2A6, 2C9, 2D6, 2E1, 3A4; Inhibits CYP3A4 (weak)

Caffeine: Substrate of CYP1A2 (major), 2C9 (minor), 2D6 (minor), 2E1 (minor), 3A4 (minor); Inhibits CYP1A2 (weak), 3A4 (moderate)

Dihydrocodeine: Substrate of CYP2D6 (minor)

DRUG INTERACTIONS
Alcohol (Ethyl): CNS Depressants may enhance the CNS depressant effect of Alcohol (Ethyl). Risk C: Monitor therapy

Alvimopan: Analgesics (Opioid) may enhance the adverse/toxic effect of Alvimopan. This is most notable for patients receiving long-term (i.e., more than 7 days) opiates prior to alvimopan initiation. Management: Alvimopan is contraindicated in patients receiving therapeutic doses of opioids for more than 7 consecutive days immediately prior to alvimopan initiation. Risk D: Consider therapy modification

Ammonium Chloride: May increase the excretion of Analgesics (Opioid). Risk C: Monitor therapy

Amphetamines: May enhance the analgesic effect of Analgesics (Opioid). Risk C: Monitor therapy

Anticonvulsants (Hydantoin): May increase the metabolism of Acetaminophen. This may 1) diminish the effect of acetaminophen; and 2) increase the risk of liver damage. Risk C: Monitor therapy

Antipsychotic Agents (Phenothiazines): May enhance the hypotensive effect of Analgesics (Opioid). Risk C: Monitor therapy

Atomoxetine: May enhance the hypertensive effect of Sympathomimetics. Atomoxetine may enhance the tachycardic effect of Sympathomimetics. Risk C: Monitor therapy

Barbiturates: May increase the metabolism of Acetaminophen. This may 1) diminish the effect of acetaminophen; and 2) increase the risk of liver damage. Risk C: Monitor therapy

CarBAMazepine: May increase the metabolism of Acetaminophen. This may 1) diminish the effect of acetaminophen; and 2) increase the risk of liver damage. Risk C: Monitor therapy

Cholestyramine Resin: May decrease the absorption of Acetaminophen. Effect is minimal if cholestyramine is administered 1 hour after acetaminophen. Risk D: Consider therapy modification

CNS Depressants: May enhance the adverse/toxic effect of other CNS Depressants. Risk C: Monitor therapy

CYP1A2 Inhibitors (Moderate): May decrease the metabolism of CYP1A2 Substrates. Risk C: Monitor therapy

CYP1A2 Inhibitors (Strong): May decrease the metabolism of CYP1A2 Substrates. Risk D: Consider therapy modification

Desmopressin: Analgesics (Opioid) may enhance the adverse/toxic effect of Desmopressin. Risk C: Monitor therapy

Imatinib: May increase the serum concentration of Acetaminophen. Risk D: Consider therapy modification

Iobenguane I 123: Sympathomimetics may diminish the therapeutic effect of Iobenguane I 123. Risk X: Avoid combination

Isoniazid: May enhance the adverse/toxic effect of Acetaminophen. Risk C: Monitor therapy

Peginterferon Alfa-2b: May decrease the serum concentration of CYP2D6 Substrates. Risk C: Monitor therapy

Pegvisomant: Analgesics (Opioid) may diminish the therapeutic effect of Pegvisomant. Risk C: Monitor therapy

QuiNIDine: May diminish the analgesic effect of Dihydrocodeine. Risk D: Consider therapy modification

Quinolone Antibiotics: May decrease the metabolism of Caffeine. Exceptions: Gatifloxacin; Gemifloxacin; Levofloxacin; Lomefloxacin; Moxifloxacin; Nalidixic Acid; Ofloxacin; Sparfloxacin; Trovafloxacin. Risk C: Monitor therapy

Regadenoson: Caffeine may diminish the vasodilatory effect of Regadenoson. Risk D: Consider therapy modification

Selective Serotonin Reuptake Inhibitors: Analgesics (Opioid) may enhance the serotonergic effect of Selective Serotonin Reuptake Inhibitors. This may cause serotonin syndrome. Risk C: Monitor therapy

Succinylcholine: May enhance the bradycardic effect of Analgesics (Opioid). Risk C: Monitor therapy

Sympathomimetics: May enhance the adverse/toxic effect of other Sympathomimetics. Risk C: Monitor therapy

Thiazide Diuretics: Analgesics (Opioid) may enhance the orthostatic effect of Thiazide Diuretics. Risk C: Monitor therapy

Vitamin K Antagonists (eg, warfarin): Acetaminophen may enhance the anticoagulant effect of Vitamin K Antagonists. Most likely with daily acetaminophen doses >1.3 g for >1 week. Risk C: Monitor therapy

ETHANOL / NUTRITION / HERB INTERACTIONS
Ethanol: Excessive intake of ethanol may increase the risk of acetaminophen-induced toxicity. Ethanol may also increase CNS depression.

PREGNANCY RISK FACTOR — C (show table)

PREGNANCY IMPLICATIONS — Reproduction studies have not been conducted with this combination.

LACTATION — Enters breast milk/not recommended

BREAST-FEEDING CONSIDERATIONS — Acetaminophen and caffeine are both excreted in breast milk. Specific information for dihydrocodeine is not available; however, similar agents (eg, codeine, morphine) are excreted in breast milk.

PRICING — (data from drugstore.com)
Capsules (Panlor DC)
356.4-30-16 mg (30): $46.99

Tablets (Panlor SS)
712.8-60-32 mg (30): $58.99

MECHANISM OF ACTION
Acetaminophen inhibits the synthesis of prostaglandins in the central nervous system and peripherally blocks pain impulse generation; produces antipyresis from inhibition of hypothalamic heat-regulating center.

Caffeine is a CNS stimulant; use with acetaminophen and dihydrocodeine increases the level of analgesia provided by each agent.

Dihydrocodeine binds to opiate receptors

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