What are the uses of Doxylamine?

Doxylamine Uses

Doxylamine is primarily used as a nighttime sleep aid and as a first-line treatment for nausea and vomiting of pregnancy, with secondary uses for allergic symptoms including runny nose and sneezing associated with upper respiratory infections.

Primary Uses

1. Sleep Aid

• Doxylamine succinate (25 mg) is FDA-approved as an over-the-counter nighttime sleep aid 1
• Indicated for occasional insomnia in adults 2
• Should be taken only at bedtime 1
• Particularly effective for maintenance insomnia (difficulty staying asleep in the last third of the night) due to its histamine H1 inverse agonist properties 2

2. Nausea and Vomiting of Pregnancy (NVP)

• Considered a safe first-line pharmacologic antiemetic therapy for NVP by the American College of Obstetricians and Gynecologists 3
• Often used in combination with pyridoxine (vitamin B6) as Diclectin
• Can be safely taken throughout pregnancy with no increased risk of congenital malformations or adverse pregnancy outcomes 3
• Recommended for moderate to severe NVP symptoms when non-pharmacological interventions and pyridoxine alone are insufficient 3

3. Upper Respiratory Symptoms

• Effective for relief of runny nose and sneezing associated with upper respiratory tract infections 4
• Provides significantly greater reduction in runny nose scores (p<0.01) and sneezing scores (p<0.001) compared to placebo 4
• Often included in combination cold medications with antitussives and decongestants 5

Contraindications and Precautions

Doxylamine should not be used in:

• Children under 12 years of age 1
• Patients with breathing problems such as asthma, emphysema, or chronic bronchitis 1
• Patients with glaucoma 1
• Patients with urinary retention or enlarged prostate 1
• Concurrent use with alcohol 1

Adverse Effects

Common side effects:

• Drowsiness (reported in 13.3% of patients) 4
• Sedation (less than other first-generation antihistamines) 4

With intranasal formulations (investigational):

• Nasal congestion
• Nasal dryness
• Frontal headache 6

Serious Risks

1. Potential for abuse and addiction

   • Case reports document doxylamine addiction with escalating doses 7
   • Monitor for signs of dependence in long-term users

2. Overdose complications

   • Rhabdomyolysis (rare but serious complication) 5
   • Secondary acute renal failure 5

Dosing Considerations

• Standard dose for insomnia: 25 mg at bedtime 1
• For NVP: Used in combination with pyridoxine, can be continued throughout pregnancy if symptoms persist 3
• For respiratory symptoms: 7.5 mg four times daily 4

Monitoring

• For insomnia: Discontinue if sleeplessness persists continuously for more than two weeks, as this may indicate an underlying medical condition 1
• For pregnancy use: Monitor for adequate symptom control and adjust dosing as needed 3
• For all uses: Monitor for sedative effects that may impair driving or operating machinery

Important Clinical Pearls

• Doxylamine has a longer half-life than many other sleep aids, making it particularly useful for maintaining sleep throughout the night 2
• When used for NVP, it follows a stepwise approach starting with non-pharmacological interventions, then pyridoxine alone, before adding doxylamine 3
• The incidence of sedative effects is lower than has been reported for other commonly used first-generation antihistamines 4