Antihistamines (Wiki)

Antihistamines are typically drugs that fight the symptoms of allergic reactions. However, many Antihistamines have, as a side effect, sedative properties, without the problem of tolerance and addiction.


Diphenhydramine (Wiki)

Brand names: Benadryl®, Dimedrol®
Formula: C17H21NO
Half life: ~ 1 to 4 hours (vague figure)
Single unit dose: Unknown
Recommended outpatient dose: 50mg [Not Verified]
Maximum outpatient dose: 100mg [Highly Questionable]

This drug is available over the counter without the need for a prescription. Interestingly, it works as an SSRI medication, inhibiting the reuptake of the monoamine neurotransmitter serotonin in the brain and was the forerunner to the famous antidepressant fluoxetine.

Doxylamine (Wiki)

Brand names: Dozile®, Restavit®
Formula: C17H22N2O
Half life: ~ 6 to 12 hours (vague figure)
Single unit dose: Unknown
Recommended outpatient dose: 10mg [Not Verified]
Maximum outpatient dose: 25mg [Not Verified]

Interestingly, this medication may in fact be a more capable sedative than the staple drug phenobarbital, a barbiturate. It is the most powerful over the counter sedative available. Doses start from 6.25mg at night to a recommended maximum of 25mg, although some countries permit a maximum daily dose of up to 50mg per day.

Hydroxyzine (Wiki)

Brand names: Atarax®, Vistaril®
Formula: C21H27ClN2S2
Half life: 20 to 25 hours
Single unit dose: Unknown
Recommended outpatient dose: 100mg per day [Not Verified]
Maximum outpatient dose: 600mg per day [Verified]

A first generation, piperzanie antihistamine, Hydroxyzine was first synthesised in the early 1950s and announced in 1956; it is an effective as an anxiolytic. Thankfully, unlike many sedative-hypnotics, the drug carries none of the addictive or dependence that other drugs display and does not have the same potential of toxicity.

Promethazine (Wiki)

Brand names: Phenergan®, Promethegan®
Formula: C17H20N2S
Half life: 16 to 19 hours
Single unit dose: Unknown
Recommended outpatient dose: 25mg per day [Verified]
Maximum outpatient dose: 60mg per day (for insomnia) [Verified]

Originally used as an antipsychotic, this drug exhibits notable sedative and hypnotic effects.