What Is Promethazine?
Promethazine is a member of a class of drugs known as phenothiazines. It works as both an antihistamine and a sedative. By blocking histamine, this medication can alleviate symptoms such as a runny nose, sneezing, and watery eyes. As a sedative, it has a calming effect and can induce sleep.
Promethazine is not a controlled substance, but it should be used with caution. This medication is available by prescription only and may be recognized as the brand name Phenergan.
How Is Promethazine Prescribed?
Promethazine is an FDA-approved drug used to treat conditions such as seasonal allergies, allergic reactions, nausea and vomiting, and motion sickness. It’s sometimes prescribed as a sedative for sleep problems or for post-surgical pain. Promethazine is typically indicated for oral, rectal, or parenteral administration and is available in tablet, liquid, suppository, and injectable forms.[1]
Promethazine is available in different doses depending on the condition it’s being used to treat, as well as the doctor’s discretion. When used for allergy relief, it’s typically taken between one and four times per day. When prescribed for motion sickness, individuals usually take it half an hour or an hour before the trip, and if needed, they may take another dose after eight to twelve hours. For nausea and vomiting, doctors typically recommend taking promethazine every four to six hours. [2]
Healthcare providers should be notified of any other medications a person is taking, as well as existing medical conditions, before prescribing promethazine. Patients should follow the instructions on the prescription precisely. One should never increase the dose of promethazine or stop taking it abruptly without their doctor’s guidance.
Promethazine Side Effects
Common Side Effects of Promethazine
People prescribed promethazine may experience common side effects, including: [3]
- Drowsiness
- Dizziness
- Ringing in the ears
- Dry mouth
- Blurred vision
- Seeing double
- Nervousness
- Fatigue
- Insomnia
These common side effects of promethazine aren’t typically serious, but if they persist for more than a few days, it may be necessary to notify a healthcare provider.
Serious Side Effects of Promethazine
Some people experience serious side effects as a result of taking promethazine, including: [4]
- Severe sleepiness
- Faintness
- Confusion
- Agitation
- Hallucinations
- Yellowing of the skin or eyes
- Seizures
- Nightmares
- Bruising easily
- Uncontrollable muscle movements, especially in the face or eyes
- Trouble swallowing
- Stiff muscles
- Nosebleeds
- Bleeding gums
- Tremors
- High fever
- Sweating
- Rapid or irregular heartbeats
- Sore throat
- Chills
People experiencing any of these serious side effects of promethazine should seek medical attention right away.
How Long Does Promethazine Stay in the System?
The effects of promethazine generally last between four and six hours, but it can remain in a person’s system for much longer. Since its half-life is between ten and nineteen hours, it can stay in the body for up to four days after the last dose. [5] However, it may still be detected by a drug test for up to 90 days.
There are some reports of promethazine giving a false positive for amphetamines on some drug screenings. If prescribed promethazine, it may be best to take the prescription to the lab on the day of the test.
Does Promethazine Show Up on a Drug Test?
Promethazine is a prescription drug, but it isn’t a controlled substance, so it’s not typically screened on a drug test, such as a urine test or blood test. There is some anecdotal evidence that promethazine may give a false positive for amphetamines, but the reason for this is unclear. [6] It could be best for individuals to take their promethazine prescription with them to the lab when being screened for illicit drugs.
Promethazine and Substance Abuse
Though not a controlled substance, promethazine is sometimes added to the concoction known as “purple drank” or mixed with other illicit narcotics such as opioids and benzodiazepines. [7]
Promethazine Overdose Risk
There have been reports of promethazine overdose, including fatal overdoses. [8] Mixing promethazine with alcohol or other central nervous system depressants like opioids can increase the risk of death from overdose. There are signs of overdose to be watchful of when taking promethazine, including: [9]
- Fainting or lightheadedness
- Dizziness
- Nausea
- Constipation
- Slow breathing
- Difficulty breathing
- Rapid heartbeat
- Widened pupils
- Loss of coordination
- Agitation
- Unusual excitement
- Repetitive twisting of hands or feet
- Loss of coordination
- Nightmares
- Stiff muscles
If a person is demonstrating the above symptoms after taking promethazine, contact the poison control helpline. Call 911 and seek immediate medical attention.
General Signs of Substance Use Disorder
Promethazine is not generally addictive but is misused when mixed with other substances, which may increase the risk of substance use disorder, including polysubstance use disorder. Some of the general signs of addiction associated with polysubstance use disorder include: [10]
- Experiencing intense cravings for substances
- Using promethazine in larger doses or for longer than originally intended
- Unsuccessfully trying to stop using substances or cut back on use
- Continuing to use substances despite worsening medical or mental health conditions
- Continuing to use substances despite them causing problems in jobs, relationships, or other areas of life
- Needing more substances to achieve the same effects
- Spending an excessive amount of time obtaining, using, or recovering from substances
- Having withdrawal effects when abstaining from substances
- Giving up other activities to use substances
- Using substances in risky situations
- Failing to meet deadlines or keep up with responsibilities due to substance use
A person need not experience all of these symptoms to qualify for a diagnosis of substance use disorder. According to the American Psychiatric Association, the presence of just two symptoms may indicate mild substance use disorder. [11] Four or five symptoms may indicate a moderate substance use disorder, while six or more symptoms could warrant a severe addiction.
Treatment Is Available
Addiction to promethazine hydrochloride or any other substance is treatable. Individuals don’t have to face substance use disorder alone. Rehabilitation counselors and treatment centers are available to provide compassionate, evidence-based care. Addiction treatment can be successful for promethazine alone or when used with other dangerous drugs like opiate drugs or benzodiazepines. Evidence-based treatments for substance use disorder include medication-assisted detoxification services, mental health services, behavioral therapy, and more.
