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Haldol (Haloperidol) Side Effects: List Of Possibilities

Haldol (Haloperidol) is a medication that is most commonly used to treat schizophrenia. In some cases it is also used to help manage acute psychosis, mania in bipolar disorder, and tics in Tourette syndrome. It is considered a first-generation “typical” antipsychotic drug and was initially approved by the FDA in 1967. Haldol is a regarded as being derived from the chemical compound “butyrophenone” and tends to function as a dopamine antagonist.

Specifically this drug yields most of its benefit for treating schizophrenia by acting on the D2 dopamine receptor and the 5-HT2 receptor. It is found to be most beneficial for cases in which people are struggling mostly with positive symptoms of schizophrenia such as hallucinations and delusions. In other words, individuals that tend to have more frequent psychotic symptoms are thought to have more success with a medication like Haldol.

Despite its overall effectiveness for managing schizophrenia, it is an older drug that tends to carry a significant number of unwanted side effects. If you have been taking this drug and/or are considering it for a treatment option, you may want to be aware of potential side effects that may occur. Compared to other antipsychotics, Haldol is less associated with weight gain but more associated with extrapyramidal symptoms.

Factors that influence Haldol side effects

When taking any antipsychotic medication, it is important to understand that there are factors that will increase prevalence and intensity of side effects. These influential factors tend to include: individual variation, drug dosage, how long you’ve been taking it, and whether you are taking any other medications.

1. Individual Variation

It is important to realize that although it is common for everyone to experience side effects, what you experience will largely influenced by your individual physiology and genetics. This is why giving two people the same dose of Haldol can result in significantly different side effects. One person may experience significant sexual dysfunction, while another person may develop a skin rash.

There’s really no telling what specific side effects you’ll experience until you take the drug. If you’re planning on taking an antipsychotic, there is a good chance you’ll experience some sort of side effects. Just realize that the quantity and severity of these effects will be highly individualized.

2. Dosage

The amount of Haldol you take on a daily basis will affect the side effects that you experience. The more of the drug you take, the more likely you will be to exhibit side effects. It should also be noted that as dosage increases, side effects tend to become more problematic and severe. With this particular medication, there are a couple ways you can choose to take it: tablets (pills) vs. IV (intra-venous) injections.

Tablets: 0.5 mg, 1 mg, 2 mg, 5 mg, 10 mg, 20 mg

When starting Haldol, the recommended dosage to treat schizophrenia ranges between 0.5 mg and 5 mg taken 2x to 3x per day. The maximum dose is typically considered 30 mg daily when initially starting. In general, the higher your dosage, the more likely you will be to have unwanted side effects. It is best to work with your doctor to reach the lowest effective dose that alleviates symptoms to minimize side effects.

Injections (IV / IM): 50 or 100 mg/ml

Haldol also comes in the form of intravenous and intramuscular injections that can be administered daily or monthly (once every 4 weeks). For the daily intravenous injections, people receive an injection of 2 mg to 5 mg every 8 hours or as necessary. The maximum dose for an individual injection is 50 mg and maximum daily dose should not exceed 500 mg.

The monthly injections are typically 10x to 20x the strength of the daily dose. This formulation is effective when administered once every 4 weeks (month) intramuscularly. This form of injection is not to be administered intravenously. It is thought that injections will lead to a significantly quicker effect of the drug on the nervous system, likely resulting in more side effects.

Since the long-term intramuscular injections cannot be manually reduced, it is recommended to first try the tablets and see how well you tolerate them. If you get the long-lasting injection and have a bad reaction or unwanted effects, it will require significant medical intervention to get the drug out of your system.

3. Time Span

How long have you been taking Haldol? If you just started taking it, the likelihood that you experience side effects is very high. Most people tend to go through an adaptation period of about 4 to 6 weeks in which their nervous system adjusts to functioning under the influence of the drug. During the initial introduction phase of the drug, the likelihood that you experience unwanted side effects is pretty high.

As your body becomes used to receiving the drug and has adapted to its influence, some side effects will likely subside. With typical antipsychotics, there are usually consistent side effects that never go away as long as you continue to take the drug. Finally there are other side effects that can develop after long-term usage. Examples of side effects that could develop over the long-term include: diabetes, tardive dyskinesia, and confusion.

4. Other Drugs

Are you currently taking any other drugs with Haldol? In many cases people are unaware that certain drugs can cause interaction side effects when combined with a typical antipsychotic like Haldol. For example, if you are also taking a benzodiazepine, it may make you significantly more sluggish and drowsy because both tend to reduce arousal.

Additionally certain pain medications, antihistamines, and tricyclic antidepressants may lead to an increase in unwanted side effects. Always talk to your doctor to get the latest information on potential contraindications and discuss any interaction effects or concerns that you may have – especially if you are on multiple medications.

Haldol Side Effects: List of Possibilities

Below are a list of possible side effects that you may experience while taking Haldol. Understand that you may not experience every single side effect listed here, this is just a list of the most commonly reported ones based on self-reports and clinical research.

  • Akathisia: Antipsychotics are associated with causing akathisia or feelings of internal restlessness that result in repetitive movements such as rocking or fidgeting. With a drug like Haldol, the likelihood that you’ll experience this symptom is relatively high compared to newer medications.
  • Anxiety: Although this drug can be very effective at reducing anxiety in some people, in other individuals it can actually make things worse. If you notice that you feel considerably more anxious than prior to starting the medication, it’s likely a side effect that you will have to put up with. This side effect isn’t as common though as Haldol tends to be a sedating drug.
  • Balance problems: This is a potent drug that can certainly affect your ability to maintain balance while walking or during activities requiring coordination. If you notice that your balance is starting to suffer, it could be from this drug.
  • Blurred vision: An unfortunate side effect associated with taking this medication is blurred vision. This can make people believe that their eyes are being damaged by the drug and/or can affect performance on jobs that require visual acuity. For some people the blurred vision will go away after a few weeks, but if it is continuous, you may want to talk to your doctor about switching medications.
  • Breast enlargement: Due to the fact that Haldol increases prolactin, it could increase the size of breasts in both males and females. As a guy, experiencing “enlarged breasts” as a result of taking this drug can be very embarrassing. Although not everyone will experience this side effect, at higher doses it is more common with any antipsychotic.
  • Constipation: You may notice that your digestion of food changes and/or you may become constipated. The constipation may improve as your body adapts to the drug, but may be noticeable the entire duration that you are on this medication. If this effect becomes problematic, talk to your doctor about it.
  • Depression: Despite the fact that this drug and other antipsychotics are utilized as antidepressant augmentation strategies, not all of them will help depressive symptoms. In particular, Haldol tends to help reduce positive symptoms of schizophrenia by reducing overactive, chaotic dopamine neurotransmission. Since it is more of a depressant, it is less likely to help with depression in the first place.
  • Dizziness: Many people feel extremely dizzy when they initially take this drug. It is common to feel “spinning sensations” as well. These sensations make it feel like the entire room or the person’s head is spinning. It can be very uncomfortable to put up with the dizziness, but as the brain adapts to the drug, this effect should improve.
  • Drowsiness: This is a drug that can make a person really drowsy. When you first start taking it, you should not be operating a motor vehicle or heavy machinery. The drowsiness can impair anyone to a significant extent. As your nervous system adjusts to the drug, the drowsiness may subside, but in general the drug tends to be sedating.
  • Dry mouth: Another uncomfortable side effect is that of experiencing dry mouth. You may feel as if your mouth is unable to produce saliva and that your entire throat is parched. This is a common side effect associated with antipsychotics that may or may not go away.
  • Extrapyramidal symptoms: In a meta-analysis that compared 15 antipsychotics, Haldol was found to be the most likely drug to cause extrapyramidal side effects. Most atypical (newer) antipsychotics are preferred over typical (older) antipsychotics because they produce less extrapyramidal effects. These effects can include things like: uncontrollable muscle spasms, akathisia, muscle rigidity, and tardive dyskinesia.
  • Headaches: When taking any psychotropic medication, it is common to experience headaches. You may notice a minor headache or a pretty extreme one to the point that it feels like you have a migraine. Headaches are usually a reaction that your nervous system has to the introduction of a new drug.
  • Heart rate increase: Some people will notice that their heart rate increases while taking this medication. This is generally considered an adverse reaction and should be reported to a doctor. If your heart rate increases significantly, it may be necessary to quit the medication. Your heart rate increase may be gradual as you continue taking the medication as well, therefore it is important to monitor for this effect.
  • Insomnia: Most people actually find that this drug helps them fall asleep easier because it is sedating and reduces dopamine. In some cases though, people can experience insomnia and restlessness, making it difficult to get a good night’s sleep. If the insomnia doesn’t go away, you may want to talk to your doctor about possible solutions.
  • Irregular periods: Women taking this drug may notice irregular menstrual cycles as a result of the drug. If you notice that you are experiencing abnormal periods and aren’t sure why, it’s likely a result of taking Haldol.
  • Itching: Another side effect that is commonly documented is that of itching. If you notice your skin starts itching like crazy, it’s likely a result of the drug. If the itching becomes extreme and you are unable to function as a result, this drug is likely not a good fit. The itching may be accompanied by a rash, but this is not always the case.
  • Lactation / Leaky breasts: Haldol is known to increase the production of the hormone prolactin, which is associated with the production of breast milk. This may lead women to experience “leaky breasts” or unwanted discharge from the nipples.
  • Memory loss: Those who take Haldol for a long-term may experience memory difficulties as a side effect. The long-term usage of antipsychotic medications may be beneficial for treating a disease, but it can result in cognitive deficits when taken over a long-term. Another antipsychotic may be preferred if memory problems become severe.
  • Muscle rigidity: This is a common extrapyramidal effect that is caused by drugs that act as dopamine antagonists. Your muscles may become increasingly tense and your posture may become stiff. If you notice that your muscles have become “rigid” it could be signs of a more serious condition known as Parkinsonism.
  • Muscle spasms: It is relatively common to experience muscle spasms on this medication. It is an older antipsychotic that is asscoiated with development of extrapyramidal symptoms. If you notice more frequent and uncontrolled spasms, talk to your doctor about it. Muscle spasms can often be a precursor to tardive dyskinesia.
  • Palpitations: If you notice that your heart rate seems to be “pounding” or you get a sensation that it is “racing,” you are likely experiencing palpitations. Palpitations can be uncomfortable and typically can increase our feelings of anxiety. Just be aware of this side effect and do your best to not panic as a result.
  • Poor concentration: While taking an antipsychotic it may seem impossible to focus on work or school-related tasks. Feeling heavy “brain fog” along with an inability to think clearly is extremely common while on Haldol.
  • Rash: In the event that a person has an allergic reaction to the drug, they may develop a rash. Sometimes the rash a person develops is associated with itchy skin, but may not always be accompanied by an “itch.” If you notice a skin rash, you probably won’t want to stay on this drug.
  • Restlessness: Feeling unable to sit still or “restless” is reported among those who take antipsychotics. This side effect may improve as you continue taking the drug, but if you’ve been taking it for awhile and the restlessness continues to worsen, it may be necessary to switch medications.
  • Sexual dysfunction: Having little to no interest in sex as well as sexual dysfunction is common while on an antipsychotic. You may notice erectile dysfunction and/or an inability to orgasm. Most people notice that antipsychotics tend to negatively affect their sex life.
  • Sleep problems: Most people will notice some changes in their sleep patterns when they start taking Haldol. It is very common to feel tired throughout the day and more sleepy than usual. Some people may also notice an increase or decrease in overall sleep quality.
  • Sweating: A common side effect to experience is an increase in the production of sweat. You may notice that you start sweating throughout the day and/or are more prone to night sweats. Keep in mind that increased sweating is very common while on psychotropic drugs.
  • Tremors: Some people report experiencing tremors or “shaking” as a side effect of this drug. Understand that some shaking may be common, but it is important to closely monitor this as it could be an indication of something more serious such as tardive dyskinesia. If you begin experiencing tremors, always report them to your doctor.
  • Urination reduction: Another side effect that is well-documented is that of reduced urination. You may find yourself using the bathroom less frequently or not producing as much urine. This may seem like a “weird” effect, but it’s relatively common.
  • Weight gain: Gaining a significant amount of weight is common on antipsychotics. The weight gain tends to be less severe with older antipsychotics like Haldol, but extrapyramidal side effects tend to be worse in older drugs. The weight gain is caused by changes in insulin, hormones, metabolism, and brain functioning as a result of this drug.

Note: It should be understood that there are more side effects than the ones listed above. The side effects listed above happen to be the most commonly reported.

Haldol: Severe Side Effects / Adverse Reactions

It is important to be aware of any potential adverse reactions that people have with Haldol. If you have an adverse reaction, it is recommended to seek immediate medical attention.

  • Anemia: It is important to closely monitor red blood cell counts during treatment with this medication. A rare adverse side effect is that of anemia or reduction in the number of red blood cells as a result of your medication. The anemia alone can cause you to feel tired, weak, confused, or shortness of breath. Unfortunately the symptoms of anemia are inherently similar to other side effects of the drug so it can be difficult to distinguish without blood testing.
  • Confusion: Although most people will experience a reduction in ability to concentrate when they take Haldol, not everyone will become confused. Becoming severely confused is considered an adverse reaction to this medication. It is characterized by impaired cognition, disorientation, and disorganization.
  • Chest pain: Some individuals may note chest pain as a result of this medication. The chest pain may be a minor ache and/or more severe. If you experience any pain in your chest, it is important to report it to your doctor.
  • Diabetes: Antipsychotics are associated with the development of Type 2 diabetes. This is usually related to changes in insulin levels and hormones that the drugs tend to make. Some speculate that an increase in overall body weight could also contribute to this effect.
  • Dystonia: This side effect is characterized by muscle spasms and twitches along with abnormal postures. If you find yourself constantly twitching and cannot seem to maintain a normal posture, it could be a sign of dystonia.
  • Fainting: Some people can experience fainting as a result of taking this drug. Usually signs of potential fainting can include: feeling lightheaded and excessive dizziness. Obviously if you feel like you may faint or have already fainted, this should be reported.
  • Fever: Changes in body temperature are common with potent antipsychotics like Haldol. You may notice minor increases in temperature throughout the course of your treatment. Usually fevers can be produced by an immune system reaction or changes as a result of the drug. In most cases your body temperature should readjust, but if this is a frequent side effect, talk to your doctor.
  • Low blood pressure: Taking Haldol has been reported to cause hypotension or abnormally low blood pressure. Your doctor should closely monitor your blood pressure for changes as a result of the medication. If your blood pressure becomes too low, it may lead to increased dizziness or fainting.
  • Neuroleptic Malignant Syndrome: Haldol is an older, typical antipsychotic that is associated with a very high risk of developing neuroleptic malignant syndrome. This is a side effect characterized by a fever, severe confusion, profuse sweating, rigidity, and balance issues. If you exhibit signs of NMS, seek immediate medical attention.
  • Parkinsonism: This side effect tends to cause movement abnormalities similar to those seen among patients with Parkinson’s disease. Examples include: tremors, slowed reflexes, speech difficulties, and stiff muscles. This is caused by deficient levels of dopamine in the brain.
  • Seizures: In rare cases, it is thought that this medication could cause seizures. These are less frequently reported, but a side effect of many psychotropic medications. If you are prone to seizures and/or experience one as a result of this drug, report it to your doctor.
  • Tardive Dyskinesia: This is a very unfortunate side effect associated with the use of antipsychotics. It is a neurological disorder that usually occurs in individuals taking typical antipsychotics at high doses for an extended period of time. This may manifest as uncontrollable body movements such as twitching, lip movements, grimaces, and excessive blinking.

Haldol: Weighing the cons (side effects) vs. pros (benefits)

Due to the significant number of side effects, it can be difficult to justify going on any antipsychotic medication to treat schizophrenia and/or bipolar disorder. For most other conditions such as depression, anxiety, or insomnia, the side effects associated with an antipsychotic, especially an older one like Haldol, are simply not worth any perceived benefits. Over the long-term there is a chance that you could develop a permanent condition such as tardive dyskinesia that you will be stuck with for life.

With Haldol, there are clearly a significant number of side effects compared to most antipsychotics. The one benefit associated with this drug is that it is older and will likely not lead to as much weight gain as newer generation antipsychotics. However, the major problem with Haldol tends to be the extrapyramidal symptoms that it often produces. If the drug is working well, it may be worth the risk of developing these unwanted side effects.

Ultimately it is up to you to decide whether this drug has enough benefit to justify the side effects. Some people may consider this to be the most effective medication for managing their hallucinations and delusions as a result of schizophrenia. For others, the medication may not work very well and cause way too many side effects. If you have any questions regarding side effects of Haldol, talk to your doctor.

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{ 3 comments… add one }
  • Kim Massengill January 15, 2016, 2:47 am

    My daughter was given 100 mg Haldol injection – and is experiencing dyskinesia (Parkinson’s like) reactions. How can we get this drug out of her system? Can we expedite? Are there any drugs to take to counter these awful effects? Please HELP!

    • Tim January 20, 2016, 2:01 am

      My son was given an Haldol injection too and has the following symptoms: drooling, sweating, tremors, restless and has trouble speaking. He’s now in a ICU and diagnosis is NMS. Get your daughter to the hospital ASAP as this is very serious if not treated. Good luck to her and wish her well!

  • Bill March 18, 2016, 11:02 pm

    My wife’s uncle, who has been on Haldol most of his adult life for treating schizophrenia, has become very difficult to understand as his speech is sometimes scrambled. Is the speech problem directly related to the long term use of Haldol?

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