Doxepin

What doxepin tablets are used for

Doxepin belongs to the tricyclic antidepressants, one of the older groups of mood medicines that is still in use. Its main job is treating depression, and it is also used for insomnia — trouble falling asleep or waking in the night — and for the anxiety that often travels with low mood. Sedation is a large part of how it helps sleep, which is why the smaller strengths are often picked for that purpose and the larger ones for depression. Doxepin tablets come as 10mg, 25mg and 75mg, all plain tablets, and they sit among the shop's antidepressants.

How it works

Two things happen at once. Doxepin slows the re-uptake of serotonin and noradrenaline, two chemical messengers involved in mood, so more of each stays available around the nerve endings. It also blocks histamine receptors, the same ones that antihistamine sleep aids act on, and that is where the calm, sleepy feeling comes from. A third action, on acetylcholine, explains the dry mouth, blurred vision and constipation many people notice. Mood changes build slowly over weeks; the sedation is there from the first dose.

When and how doxepin is taken

Most people take it once a day in the evening or at bedtime, because the drowsiness is strongest in the hours after a dose. If depression is the main target, some take it in divided doses across the day instead. Doxepin is generally started at a low strength and increased step by step, and it is taken at the same point in the day each time. A heavy night of drinking is worth avoiding while you are on it: alcohol stacks with the sedation and can leave you dizzy, unsteady or aware of a racing heartbeat.

Side effects worth knowing about

Dry mouth, sleepiness, blurred vision, constipation, dizziness on standing, sweating and weight gain are the ones people mention most, and they usually settle after the first week or two. Less often, doxepin disturbs the rhythm of the heart, and a fluttering chest, palpitations or a faint are signs of that. Fever with stiff muscles, shivering, confusion or agitation needs urgent treatment. Sudden severe confusion, or finding it hard to pass urine at all, also needs attention. Taking far too much doxepin at once is dangerous.

Doxepin and other medicines

MAOIs, a separate group of antidepressants, do not mix with doxepin and can push blood pressure or serotonin to unsafe levels. Sleeping tablets, opioid painkillers, antihistamines and alcohol all add to the sedation. A few medicines, including certain antifungals and cimetidine, slow the body's clearing of doxepin and let its level creep up. Keep the strips in their box, somewhere dry and out of the sun and heat.