Anticholinergics are a broad class of medications used to treat a variety of conditions that affect the contraction and relaxation of muscles.
These include medications used to treat overactive bladder, Parkinson's disease, diarrhea, vomiting, asthma, chronic obstructive pulmonary disease (COPD) , muscle spasms, irritable bowel syndrome (IBS) , and other conditions. that involve involuntary muscle movements.
How do these drugs work?
Acetylcholine is a substance made by the body that works as a neurotransmitter. It works on nerve cells by sending chemical messages to the brain. Therefore, acetylcholine can regulate certain biological functions by speeding up or slowing them down.
These include the skeletal muscles involved in movement and the smooth muscles of the heart, stomach, intestines, urinary tract, and lungs. The cells involved in the contraction of these muscles have nerve receptors. Those who are susceptible to acetylcholine are considered cholinergic.
When muscle function is impaired, there are drugs that can block acetylcholine by binding to cholinergic receptors. Without chemical messengers, contractions can be stopped and symptoms alleviated.
We call this the anticholinergic effect.
Anticholinergic side effects
In addition to muscle contractions, certain types of acetylcholine regulate memory, learning, and sensation. Because anticholinergics are not specific for the types of receptors they block, they can cause a number of side effects that affect both the body and the mind .
- Dry mouth due to suppression of the salivary glands.
- Sore throat due to decreased mucus production.
- Without sweating
- Increased body temperature
- Photosensitivity due to delayed pupil dilation
- Blurred vision or double vision
- Increased heart rate to compensate for changes in vascular function.
- Poor coordination due to poor muscle control.
- Incontinence during sleep
- Intestinal leak
- Memory problems
- Inability to concentrate
- Tendency to be easily frightened
Several drugs achieve their therapeutic goals due to their anticholinergic effect. For example, by slowing down bowel movements, a person can get rid of diarrhea. Similarly, the respiratory restriction associated with asthma and COPD can be improved when cholinergic receptors in the lungs are blocked .
Antispasmodics are one of the classes of drugs for which the anticholinergic effect is believed to be beneficial. Although side effects are common, short-term use combined with a low dose generally means that symptoms can be controlled.
Antispasmodic drugs with anticholinergic action include:
- Bentil (dicyclomine)
- Buscopan (hyoscine butyl bromide)
- Levsin (hyoscyamine)
- Lomotil (atropine / diphenoxylate)
- Enablex (darifenacin)
- Pamin (methylscopalamine)
- Spiriva (tiotropium bromide)
- Symmetrel (amantadine)
- Vesicar (solifenacin)
Unintended anticholinergic effects
On the other hand, there are drugs that have unwanted anticholinergic effects. These include certain antidepressants and antipsychotics that increase or decrease the amount of neurotransmitters dopamine and serotonin to alter a person's mood. In some cases, medications can block acetylcholine and cause anticholinergic side effects.
The problem, of course, is that antidepressants and antipsychotics are often prescribed long-term, making treating symptoms even more difficult.
Antidepressants and antipsychotics with anticholinergic effects include:
- Elavil (amitriptyline)
- Norpramine (desipramine)
- Tofranil (imipramine)
- Pamelor (nortriptyline)
- Paxil (paroxetine)
- Thorazine (chlorpromazine)
- Clozaril (clozapine)
- Zyprexa (olanzapine)
- Mellaril (thioridazine)
In between these two extremes, there are times when low doses of antidepressants can be used to treat chronic pain and IBS. A similar effect is achieved with some low-dose antipsychotics and with Parkinson's disease.
By weighing the pros and cons of anticholinergic effects, healthcare providers can find the correct medication and dosage to treat without the burden of side effects.
Get the word of drug information
If you experience unbearable side effects due to the anticholinergic effects of the drug, talk to your doctor. Depending on your healthcare provider, your doctor may lower the dose or find a suitable replacement.
However, you should not stop taking any medications without first talking to your doctor. This can sometimes cause adverse effects (especially with certain antidepressants) if treatment is not gradually stopped.