Dosing and uses of Alka-Seltzer PM, Bayer PM (aspirin/diphenhydramine)
Adult dosage forms and strengths
aspirin/diphenhydramine
tablet
- 325mg/38mg
- 500mg/38.3mg
Temporary Relief of Headache & Aches with Accompanying Sleeplessness
Alka-Seltzer PM: 2 tablets with water qHS PRn
Bayer PM: 2 tablets with water qHS PRn
Pediatric dosage forms and strengths
aspirin/diphenhydramine
tablet
- 325mg/38mg
- 500mg/38.3mg
Temporary Relief of Headache & Aches with Accompanying Sleeplessness
Alka-Seltzer Pm
- <12 years old: Do not use
- >12 years old: 2 tablets with water qHS PRN
Bayer Pm
- <12 years old: Do not use
- >12 years old: 2 tablets with water qHS PRN
Alka-Seltzer PM, Bayer PM (aspirin/diphenhydramine) adverse (side) effects
Frequency not defined
Hypotension
Tachycardia
Agitation
Cerebral edema
Coma
Confusion
Dizziness
Headache
Subdural or intracranial hemorrhage
Lethargy
Hives
Rash May potential peptic ulcer & cause stomach distress or heartburn
Dyspepsia
GI bleeding
Ulceration & perforation
Nausea
Vomiting
Prolonged prothrombin time
Sedation
Sleepiness
Urinary retention
Xerostomia
Increased appetite
Warnings
Contraindications
Hypersensitivity
Liver damage
Hypoprothrombinemia
Vitamin K deficiency
Bleeding disorders
Asthma
Due to association of aspirin w/ Reye syndrome, do not use in children (<16 y) with viral infections
Use within 14 days of MAO inhibitor therapy
Narrow-angle glaucoma
Symptomatic prostate hypertrophy
Bladder-neck obstruction
Cautions
Aspirin: May cause transient decrease in renal function and aggravate chronic kidney disease; avoid use in patients with severe anemia, history of blood coagulation defects, or taking anticoagulants
Diphenhydramine: May cause significant confusional symptoms; not for administration to premature or full-term neonates
Pregnancy and lactation
Pregnancy category: D, avoid aspirin during pregnancy, especially during third trimester (risk for 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 PM, Bayer PM (aspirin/diphenhydramine)
Mechanism of action
Aspirin: stronger inhibitor of both prostaglandin synthesis & platelet aggregation than other salicylic acid derivatives; acetyl group responsible for inactivation of cyclooxygenase via acetylation; hydrolyzed rapidly in plasma, & elimination follows zero order pharmacokinetics
Aspirin irreversibly inhibits platelet aggregation by inhibiting platelet cyclooxygenase; this, in turn, inhibits conversion of arachidonic acid to PGI2 (potent vasodilator and inhibitor of platelet activation) and thromboxane A2 (potent vasoconstrictor and platelet aggregate)
Diphenhydramine: may cause significant confusional symptoms; not for administration to premature or full-term neonates
