Home / Pharmaceuticals / Side Effects of over the Counter Sleep AIDS

Side Effects of over the Counter Sleep AIDS

It’s a well known fact that humans need sleep. Without it, your body can’t regenerate properly, and you lose the ability to function in optimum condition. Given the importance of a decent night’s sleep, it comes as no surprise that sleep problems are one of the most prevalent complaints expressed to general practitioners. More than 50 per cent of people express dissatisfaction or insomnia symptoms, of which 9.5 per cent show signs of clinical insomnia.

For people with insomnia or sleep difficulties, sleeping pills can be a godsend. The medication of the past is a far cry from today’s options, and the standard benzodiazepines prescribed don’t carry the risks that barbiturates did. Benzodiazepines aren’t for everyone though, and they do have their own side effects and dangers. If you have light insomnia and would prefer to try an over-the-counter remedy first, there are a few effective medications available:

Valerian root

Valerian is a perennial plant with sedative and anxiolytic effects, making it useful in treating mild sleep problems and anxiety. It works by acting on the same receptors as benzodiazepines, albeit to a much weaker degree. It doesn’t generally prove very effective for someone with clinical insomnia, but for mild sleep problems it can be extremely effective and absent of side effects. Daytime sedation may occur the morning after use in some people, but the prevalence is less compared to other sleeping aids. The use of this sleep aid should be discussed with a doctor or pharmacist prior to use to ensure it won’t interact with anything you’re taking.


Melatonin is a hormone involved in the regulation of the circadian rhythm, which is the body’s sleep cycle. Levels of the hormone are highest at night, and lower in the mornings, and are largely reliant on light. Exposure to too much light prior to sleeping can result in less melatonin being released and poorer sleep. As such, it is possible to use melatonin as a supplement to sleep better, and in particular, for correcting sleep patterns. Use of this hormone should be under consultation of a doctor as incorrect use can cause side effects like disruption of sleep cycles.


Diphenhydramine belongs to a group of antihistamines called the first generation antihistamines, which all cause strong sedation due to their effect on reducing histamine in the central nervous system. Diphenydramine is the drug name for medications like Benadryl and Unisom, and is used for allergies, motion sickness, and insomnia. A doctor or pharmacist should be consulted before use, and a dosage of 25 – 50 mg is common for insomnia. Unisom is a sleep aid containing diphenhydramine, but the products marketed towards allergies have the same effect and dosage, with the added benefit of being cheaper. A doctor will be able to tell you which product works out best and cheapest for you.

The first generation antihistamines are not without side effects, of which the most common is drowsiness that persists into the next day. Depending on the dosage required, they can also increase the duration of sleep as they all have long half lives. If affected, you should avoid driving or operating machinery whilst sedated. It may also cause dizziness and dry mouth, which are due to the first generation antihistamines being potent anticholinergics which block a neurotransmitter called acetylcholine which is necessary to alertness and memory.

This medicine interacts with other sedating drugs like opiate painkillers and alcohol, as it will increase the side effects of these and can cause severe respiratory depression. The tricyclic antidepressants can also interact with first generation antihistamines as these antidepressants also have anticholinergic side effects, leading to increased risk of dry mouth, disorientation, and memory deficit.


Doxylamine is another first generation antihistamine, with sedation that even rivals prescription hypnotics like temazepam. It is sold under brand name products like Dozile and Restavit, generic sleep aids, and under the Unisom brand, causing common confusion over this medication and the diphenhydramine version of Unisom.

Sleep is induced in the same dosages as diphenhydramine and the side effects are the same. The main difference is that doxylamine’s sedative effect is stronger, and due to the drug’s long half life it can last longer, leading to significant daytime sleepiness, and disorientation. Because of the strong sedative effect, it is also imperative that you don’t mix it with other depressant drugs like opiates and alcohol, and only use doxylamine under the direction of a doctor or pharmacist.

When used correctly, OTC sleeping aids can be extremely beneficial to keeping insomnia and sleep problems under control, and are cheaper and more available than prescription hypnotics. As long as you consult with your health practitioner before deciding to use them, the risk of side effects will be minimal, allowing you to enjoy a happy night’s sleep.