Tips for tapering promethazine / Phenergan

[DaisyBell]

Does anyone have ideas on a tapering schedule for those that have been using Phenergan more than 6 months. It comes in 10 and 25 mg oral tablets. It has moderate anticholinegic effects and is a mild dopamine antagonist alongside strong H1 histamine action. Given that I assume tapering is important.

[ChessieCat]

I think Phenergan is available as a liquid.  That might be the easiest way to get doses.

[DaisyBell]

47 minutes ago, ChessieCat said:

I think Phenergan is available as a liquid.  That might be the easiest way to get doses.

Thanks ChessieCat. Wondering what time schedule e.g 25 % drop every week ok? Also read that liquid is absorbed more so may be best to stay with tablets. 

[Altostrata]

@DaisyBell How often are you taking promethazine? It's basically an antihistamine. Are you taking it for sleep?

 

https://www.drugs.com/monograph/promethazine-hydrochloride.html

 

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Duration

Duration of sedative effects usually about 2–8 hours^{117 133 a b} (depending on the dose and route of administration);^{a b} effects may persist for 12 hours.^{100 117 133}

....

Half-life

9–16 hours (following IV use) and about 9.8 hours (following IM use).¹¹⁷

 

 

If you're only taking it only once a day, it doesn't need much tapering. You might reduced it by 25% every few days.

 

In the US, it comes in a liquid form.

[DaisyBell]

31 minutes ago, Altostrata said:

@DaisyBell How often are you taking promethazine? It's basically an antihistamine. Are you taking it for sleep?

 

https://www.drugs.com/monograph/promethazine-hydrochloride.html

 

 

If you're only taking it only once a day, it doesn't need much tapering. You might reduced it by 25% every few days.

 

In the US, it comes in a liquid form.

Thank you so much. I've taken 25 mg nearly per day for between 6-12 months. I stopped C T a few days ago and then two days later started crying at everything.

[DaisyBell]

And yes for sleep 😴 

[Altostrata]

Did your sleep pattern change after you stopped it?

[Songbird]

Promethazine is a phenothiazine drug,  closely related to other meds used as anti-psychotics, so I would be inclined to be cautious with tapering speed.  You may be able to buy it as a liquid.

[DaisyBell]

Yes I started to wake at 3am on second day after CT. I also take melatonin 1mg. I need to stop it for longer to see if there's a profound effect on my sleep patterns. 

 

I can only buy tablets. Which is fine.

 

Just need to know tapering schedule for safe withdrawal given its properties beyond its histamine action. Searched the internet without finding anything about a tapering schedule. I also searched for a taper schedule for Benadryl (thinking it could be similar) and found nothing. 

 

 

[Songbird]

I would taper by how my body feels, rather than a strict timetable.  Try a reduced dose for a few days, maybe a 25% drop as Alto suggested, and see how it goes.  If you do have symptoms from the drop, you can hold until they ease off.  I've tapered off quite a few things this way.  You can buy Phenergan elixir in New Zealand - if you can't get it in your local pharmacy, it is available from online pharmacies (e.g. Netpharmacy).

[DaisyBell]

Thank you Alto, Songbird and Chessie cat.  

[Songbird]

Keep us updated, DaisyBell.

[DaisyBell]

As an update -  I'm fine. Came off of phenergan over two weeks by holding a dose for three days then halving or reducing it a bit.  No rebound insomnia.

[Altostrata]

Thanks, @DaisyBell

[Noclue87]

On 12/28/2018 at 5:49 PM, DaisyBell said:

As an update -  I'm fine. Came off of phenergan over two weeks by holding a dose for three days then halving or reducing it a bit.  No rebound insomnia.

 

Hi Daisybell can I ask whether you had any withdrawal symptoms at all? Thanks

 

Edited January 4, 2019 by ChessieCat
added quote to post

[DaisyBell]

I have withdrawal symptoms from coming off Lexapro four years ago. However I didn't notice any exacerbation or additional ones when I came off slowly over two weeks. I did notice difficulty sleeping for a night or two when I CT initially.  After that night or two I went back on it and tapered. Who knows if it was a new symptom or just part of my original withdrawal from Lexapro. 

[Noclue87]

You still have withdrawal four years later??? My goodness!

[Noclue87]

What sort of taper did you do please? How much and how often etc any info would be appreciated. I’ve been taking 25mg-50mg normally 25mg since 28th november not every day but most 

[voyteck]

I just wanted to share with you some of my suspicions regarding promethazine (US: Phenergan).
Some time ago I made an attempt (second) to lower my promethazine. One reason was it was exacerbating my withdrawal symptoms (specific headaches and horrible dry mouth). By the way thanks again to @Altostrata for her advice (no psychiatrist - and I talked to two - even suggested that!) - it helped a lot. The other reason was that I read somewhere long ago someone had some problems after quitting similar antihistamine after chronic administration.

So, a few months ago I lowered to 18,75 mg and 2 months ago (07 Jan) I lowered to 12,5. Thankfully, my sleep didn't deteriorate (which doesn't mean it's good), so I was content. But about 4 weeks ago I noticed some rash on my torso - not a big problem cause it didn't itch. But last couple of days it got worse - rash and itching. For those who know niacin "flush" - a bit like that.

I did some research and found similar experiences of chronic hydroxyzine users here: https://www.reddit.com/r/TS_Withdrawal/comments/7s2s6v/withdrawal_itching_from_hydroxyzine/.
As I wrote it's only suspicion. If it's true then it looks like it took 1 month for symptoms to occur, and 2 months to get even worse.
Just to emphasize: I've never had any food related rashes (the "only" allergy I have is grass/hay and it has different symptoms).

 

 

 

[ChessieCat]

histamine-food-intolerance

[Noclue87]

How long have you been taking and what dose? 

[Altostrata]

Have you taken any other drug recently?

 

 

https://medlineplus.gov/druginfo/meds/a682284.html#side-effects

 

 

Quote

 

Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately:

• wheezing
• slowed breathing
• breathing stops for a short time
• fever
• sweating
• stiff muscles
• decreased alertness
• fast or irregular pulse or heartbeat
• faintness
• abnormal or uncontrollable movements
• hallucinations (seeing things or hearing voices that do not exist)
• confusion
• overwhelming or unmanageable fear or emotion
• seizures
• uncontrollable shaking of a part of the body
• unusual bruising or bleeding
• sore throat, fever, chills, and other signs of infection
• uncontrolled eye movements
• tongue sticking out
• abnormal neck position
• inability to respond to people around you
• yellowing of the skin or eyes
• rash
• hives
• swelling of the face, eyes, lips, tongue, throat, arms, hands, feet, ankles, or lower legs
• hoarseness
• difficulty breathing or swallowing

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

 

 

[Altostrata]

About promethazine https://www.ncbi.nlm.nih.gov/books/NBK544361/

 

Quote

Promethazine is a medication used to manage and treat allergic conditions, nausea and vomiting, motion sickness, and sedation. It also has off-label uses for nausea and vomiting in pregnancy. Promethazine is a phenothiazine derivative with antidopaminergic, antihistamine, and anticholinergic properties. This activity reviews the FDA approved-indications, mechanism of action, administration, dosing, adverse drug reactions, contraindications, warning, precautions, monitoring, and toxicity of promethazine. 

....

Mechanism of Action

Promethazine is a phenothiazine derivative with antidopaminergic, antihistamine, and anticholinergic properties. Other phenothiazine derivatives include prochlorperazine and chlorpromazine. Promethazine works as a direct antagonist at the mesolimbic dopamine receptors and alpha-adrenergic receptors in the brain. Promethazine exhibits its antihistamine effects as an H1-receptor blocker.[11][12]

 

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Promethazine has several routes of administration, including oral, rectal, intramuscular, and intravenous. The tablets, solutions, and suppository dosage is generally 12.5 mg to 50 mg.

• Promethazine hydrochloride injection solution: 25 mg/mL; 50 mg/mL
• Promethazine hydrochloride oral solsution: 6.25 mg/5 mL
• Promethazine hydrochloride suppository: 12.5 mg; 25 mg; 50 mg
• Promethazine hydrochloride oral syrup: 6.25 mg/5 mL
• Promethazine hydrochloride oral tablets: 12.5 mg, 25 mg, 50 mg

Promethazine should be given with food, water, or milk to decrease gastrointestinal discomfort when administered orally.

....

In pediatrics, promethazine has the same routes of administration as adults. However, dosing adjustments are necessary based on the weight of the patient and the indication. Utilizing the lowest dose of efficacy is recommended. There are no dosage adjustments for renal or hepatic impairment.

 

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Adverse Effects

There are several potential adverse effects of promethazine administration related to its mechanism of action. The most common side effects include sedation, confusion, and disorientation, which may impair physical and mental abilities. However, in some cases, promethazine may paradoxically cause excitability, restlessness, or rare seizures.

 

Promethazine’s anticholinergic properties may cause side effects, including blurred vision, xerostomia, dry nasal passages, dilated pupils, constipation, and urinary retention. Due to these effects, the American Geriatrics Society categorizes promethazine as a potentially inappropriate drug for the elderly.[16]

 

Promethazine’s antidopaminergic properties may result in extrapyramidal symptoms, including pseuodoparkinsonism, acute dystonia, akathisia, and tardive dyskinesia. Promethazine, therefore, may worsen symptoms in patients with Parkinson disease.[16]

 

Less common adverse effects that prescribers should be aware of include:

• The neuroleptic malignant syndrome may also have associations with promethazine usage, which manifests as increased body temperature, confusion or altered mental status, sweating, autonomic instability, and “lead pipe” rigidity.
• Cardiovascular side effects include arrhythmias and hypotension.
• Reports also exist of liver damage and cholestatic jaundice with its use.
• Bone marrow suppression, potentially resulting in agranulocytosis, thrombocytopenia, and leukopenia.
• Depression of the thermoregulatory mechanism resulting in hypothermia/hyperthermia.

 

 

 

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Drug Interactions

Central-Nervous-System Depressants: Promethazine may intensify, increase, or prolong the sedative action of other CNS depressants, such as tricyclic antidepressants, sedatives/hypnotics, narcotics, narcotic analgesics, alcohol, general anesthetics, and tranquilizers; therefore, those medicines should be avoided or administered in a lower dosage to patients taking promethazine concomitantly. When promethazine is concomitantly administered, the dose of barbiturates should be reduced by at least 50%, and narcotics by 25% to 50%. Dosage must be individualized according to the patient's clinical presentation. High amounts of promethazine relative to narcotics may lead to motor hyperactivity and restlessness in the patient with pain, and these symptoms normally disappear with adequate pain management.

 

Anticholinergics: Concomitant use of other medicines with anticholinergic properties should be done with caution.

 

Monoamine Oxidase Inhibitors (MAOI): Concomitant use can result in drug interactions, including an increased incidence of EPS.

 

Drug/Laboratory Test Interactions: Some laboratory tests may be altered in patients receiving promethazine therapy. Diagnostic pregnancy test results based on immunological reactions of HCG and anti-HCG could result in false-positive or false-negative interpretations. Also, a glucose tolerance test may report falsely elevated blood glucose levels in patients receiving promethazine.

 

 

How to go off promethazine

From 2018 Deprescribing Guide for Sedating Antihistamines from Australia NSW Therapeutic Advisory Group Inc (pharmacist organization):

 

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• In general, wean gradually by 25-50% of the daily dose every 1-4 weeks.
• If reason for deprescribing is serious adverse effects, wean faster or cease immediately.