aspirin/chlorpheniramine/dextromethorphan (Alka-Seltzer Plus Flu)
Classes: Cough/Cold, Non-narcotic Combos; Analgesic/Antihistamine/Antitussive Combos
Dosing and uses of Alka-Seltzer Plus Flu (aspirin/chlorpheniramine/dextromethorphan)
Adult dosage forms and strengths
aspirin/chlorpheniramine/dextromethorphan
tablet, effervescent
- 500mg/2mg/15mg
Temporary Relief of Common Cold Cough & Upper Respiratory Symptoms
Alka-Seltzer Plus Flu: 2 tablets fully dissolved in 4 oz of water q6hr; not to exceed 8 tablets/day
Pediatric dosage forms and strengths
aspirin/chlorpheniramine/dextromethorphan
tablet, effervescent
- 500mg/2mg/15mg
Temporary Relief of Common Cold Cough & Upper Respiratory Symptoms
Alka-Seltzer Plus Flu
- <12 years: Ask a pediatrician
- >12 years: 2 tablets fully dissolved in 4 oz of water q6hr; not to exceed 8 tablets/day
Alka-Seltzer Plus Flu (aspirin/chlorpheniramine/dextromethorphan) adverse (side) effects
Frequency not defined
Agitation
Agranulocytosis
Anorexia
Cerebral edema
Coma
Confusion
Depression
Dizziness
Dyspepsia
Dysrhythmias
Euphoria
Fatigue
GI bleeding
Headache
Hemolytic anemia
Hives
Hypotension
Insomnia
Irritability
Lethargy
May potentiate peptic ulcer and cause stomach distress or heartburn
Nausea
Palpitations
Prolonged prothrombin time
Rashes
Sedation
Subdural or intracranial hemorrhage
Tachycardia
Thickening of bronchial secretions
Thrombocytopenia
Tremors
Ulceration and perforation
Vomiting
Wheezing
Warnings
Contraindications
Hypersensitivity
Liver damage
Hypoprothrombinemia
Vitamin K deficiency
Bleeding disorders
Asthma
Due to association of aspirin with Reye syndrome, do not use in children (<16 years) with viral infections
Narrow-angle glaucoma
Symptomatic prostate hypertrophy
Bladder-neck obstruction
Stenosing peptic ulcer
Cautions
Aspirin may cause transient decrease in renal function and aggravate chronic kidney disease; avoid use in patients with severe anemia, with history of blood coagulation defects, or taking anticoagulants
Dextromethorphan: do not take for persistent or chronic cough associated with smoking, asthma, or emphysema, or if it is accompanied by excessive phlegm unless directed by a healthcare provider; may slow respiration rate
Chlorpheniramine: may cause significant confusional symptoms; not for administration to premature or full-term neonates
Pregnancy and lactation
Pregnancy category: D; avoid aspirin during pregnancy, particularly in third trimester (risk of premature closure of ductus arteriosus)
Lactation: excreted in breast milk; do not breast feed
Pregnant or breastfeeding patients should seek advice of health professional before using OTC drugs
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Alka-Seltzer Plus Flu (aspirin/chlorpheniramine/dextromethorphan)
Mechanism of action
Aspirin: stronger inhibitor of both prostaglandin synthesis and platelet aggregation than other salicylic acid derivatives; acetyl group is responsible for inactivation of cyclooxygenase via acetylation; hydrolyzed rapidly in plasma, and elimination follows zero order pharmacokinetics
Aspirin irreversibly inhibits platelet aggregation by inhibiting platelet cyclooxygenase; this leads to inhibition of conversion of arachidonic acid to PGI2 (potent vasodilator and inhibitor of platelet activation) and thromboxane A2 (potent vasoconstrictor and platelet aggregate)
Chlorpheniramine: blocks muscle responses in histamine and antagonizes constrictor effects of histamine on respiratory smooth muscle
Dextromethorphan: cough suppressant that acts centrally on cough center in medulla
Pharmacokinetics
Aspirin
- Bioavailability: 80-100%
- Onset: 5-30 min (PO); 1-2 hr (PR)
- Duration: 3-6 hr (PO); >7 hr (PR)
- Peak plasma time: 0.25-3 hr (PO); 4-5hr (PR)
- Vd: 0.15-0.2 L/kg
- Protein binding: 90-95%
- Metabolism: Liver (microsomal enzyme system)
- Half-life: 2-3 hr (low dose); 15-30 hr (higher dose)
- Renal clearance: 80-100%
- Excretion: Urine (80-100%)
Chlorpheniramine
- Peak plasma time: 2-3 hr
- Peak plasma concentration: 7.2 ng/mL
- Distribution (Vd): 4-7 L/kg (children); 6-12 L/kg (adults)
- Metabolism: GI mucosa, liver
- Excretion: Urine
- Half-life : 10-13 hr (children); 14-24 hr (adults)
Dextromethorphan
- Onset: 15-30 min
- Duration: 3-6 hr
- Metabolism: Hepatic P450 enzyme CYP2D6
- Excretion: Urine
- Half-life: 2-4 hr (extensive metabolizers); 24 hr (poor metabolizers)
- Peak plasma time: 2-3 hr