Tricyclic Antidepressants
Old Antidepressant Drugs Used for Insomnia, Pain, IBS, FM and More
Oct 3, 2008
Antidepressants are often prescribed for a variety of maladies, even if the patient is not depressed. Often this is because the doctor feels that the issues are psychiatric or psychosomatic, but some antidepressants also have valid uses in non-depressed patients.
Tricyclic Antidepressants
Tricyclic antidepressants (TCAs) are an old class of antidepressive drugs, much older than Prozac and other SSRIs. The first TCA imipramine was discovered back in the 1950s, when psychopharmacology was still a new science. The name "tricyclic" comes from their molecular structure which contains three rings of atoms.
The TCAs are effective antidepressants, but because they tend to cause more side effects than newer drugs, they are rarely used to treat depression any more. They are, however, still commonly used in the treatment of chronic pain, sleep disorders and some other conditions, usually in doses much smaller than would be used for depression.
The SSRIs are fairly selective for serotonin, as their name, selective serotonin reuptake inhibitors, implies. TCAs on the other hand are far from selective. They increase brain levels of serotonin, but also norepinephrine (noradrenaline). In addition they block histamine receptors, muscarinic acetylcholine receptors and alpha adrenergic receptors and have some other actions.
Uses
The increased levels of serotonin and norepinephrine are responsible for the antidepressive effects of the TCAs. The sedative and pain relieving effects of the drugs, however, are thought to result mostly from other mechanisms of action.
The TCAs are used to treat many kinds of chronic pain, especially neuropathic pain like diabetic neuropathy. They are not painkillers as such and cannot be taken "as needed"; daily use is required. They are also used in the prevention of migraines and other headaches.
TCAs can help irritable bowel syndrome (especially the pain caused by it) and bladder problems, such as overactive bladder and interstitial cystitis. Most TCAs are very sedative and can be used to treat insomnia.
Because the TCAs affect so many different targets, they can help a variety of symptoms. This is why they are often used in conditions like fibromyalgia which have many different symptoms. Remember that you always have the right to know why you are prescribed a medication, so if you do not understand the reason, do not hesitate to ask your doctor.
The Drugs
Amitriptyline (Elavil) is the best known and most commonly used drug of this class, but it may also be the most poorly tolerated. Nortriptyline (Pamelor), a metabolite of amitriptyline, is usually better tolerated and not as sedative. Protriptyline (Vivactil) is quite different from these two, being more energizing. It has even been used to treat ADHD. It is only available in the United States.
Clomipramine (Anafranil) is fairly selective for serotonin. It has been used to treat OCD and narcolepsy. Imipramine (Tofranil) is mostly used for refractory depression and sometimes enuresis (bedwetting). Its metabolite desipramine (Norpramin) may be the best tolerated tricyclic. Desipramine is also quite stimulating and has been used for ADHD.
Trimipramine is thought to have a different mode of antidepressive action than other tricyclic drugs. It is also used as a sedative and for IBS. Trimipramine (Surmontil) and dosulepin/dothiepin (Prothiaden) may be the best tricyclic drugs for anxiety. The TCA with the strongest antihistamine activity is doxepin (Sinequan), so it may be good for those for allergies.
Pros and Cons
The TCAs help many different conditions and are very inexpensive. Almost all doctors are familiar with them. Unfortunately even low doses of these drugs can cause bothersome side effects, such as daytime sedation, weight gain, dry mouth, constipation, dizziness and palpitations and many patients end up having to discontinue use.
Somewhat ironically, TCAs are usually no longer prescribed to patients with severe depression. They might be helpful in cases where other antidepressants haven't brought relief, but they are also very toxic in overdose and thus not dispensed to patients who might be suicidal. If you are taking TCAs, be very careful to keep the pills out of reach of children.
See Also
Different Types of Antidepressants
