Trihexyphenidyl 2mg

Trihexyphenidyl
Description: Anti-Parkinson Agent, Anticholinergic; Anticholinergic Agent

CSA NA – FDA Approved – REMS (N) – Can Ship

Trihexyphenidyl has a direct inhibitory effect on the parasympathetic nervous system. It also has a relaxing effect on smooth musculature via both direct action on the muscle itself and indirectly through parasympathetic nervous system.

Drug-induced extrapyramidal symptoms (treatment); Parkinsonism

Before starting Trihexyphenidyl make sure your physician is aware of any allergies or medications you currently take, if you have cardiovascular disease, a GI obstruction, glaucoma, hepatic impairment, prostatic hyperplasia/urinary stricture, have cognitive impairment, a psychiatric disorder, renal impairment, are pregnant, or breastfeeding. Trihexyphenidyl use has been associated with rare but potentially serious adverse events such as anhidrosis/hyperthermia, anticholinergic effects, CNS depression, and precipitation of narrow angle glaucoma.

Oral: Initial: 1 mg/day; increase as necessary to usual range: 5 to 15 mg/day in 3 to 4 divided doses.

How to Take: May be administered before or after meals (if excessive dry mouth develops, consider administering before meals unless it causes nausea; postencephalitic patients who are prone to excessive salivation may prefer to take after meals); tolerated best if given in 3 daily doses and with food. High doses (>10 mg/day) may be divided into 4 doses (at each meal and at bedtime). May be taken before or after meals; tolerated best if given with food.

You Need to Avoid:  Significant drug interactions exist, requiring dose/frequency adjustment or avoidance so avoid starting any new medications without consulting prescriber. Prophylactic use is generally not recommended to prevent antipsychotic-associated extrapyramidal symptoms Have prescriber reduce dosage gradually if needed as dose reduction or discontinuation of trihexyphenidyl has been associated with neuroleptic malignant syndrome (NMS), exacerbation of Parkinsonism, and withdrawal symptoms including tension, irritability, perspiration, palpitations, headache, insomnia, abdominal distress, anorexia, faint or choking feelings, nausea, and photophobia.

Tachycardia, agitation, confusion, delusions, dizziness, drowsiness, euphoria, hallucination, headache, nervousness, paranoia, psychiatric disturbance, skin rash, constipation, intestinal obstruction, nausea, parotitis, toxic megacolon, vomiting, xerostomia, urinary retention, weakness, blurred vision, glaucoma, increased intraocular pressure, mydriasis

Note the frequency of side effects has not been determined in clinical trials

1. What do I do if side effects are intolerable?
   If side effects are causing a lot of distress speak to your physician as soon as possible to discuss options.
2. What is tardive dyskinesia?
   Tardive dyskinesia is a movement disorder that is sometimes irreversible and involves involuntary movements which can impair daily function.  It generally occurs with long term use of dopamine blocking agents.  This mechanism can be compared to Parkinson’s disease due to both involving reduced dopamine resulting in involuntary movement.
3. What is Neuroleptic Malignant Syndrome?
   NMS is a rare but serious reaction from significant blockade of dopamine which can occur from antipsychotic medications or from being on high dosages of levodopa (dopamine analogue) and stopping suddenly.  Presents initially as muscle cramps, tremors, fever, unstable blood pressure, and sudden changes in mental status.  As it progresses over 8-40 hours it can lead to complications of rhabdomyolysis, hyperkalemia, kidney failure, or seizures.  Seek medical attention immediately if this reaction is suspected.