Trihexyphenidyl Hydrochloride

Indications and usage: Trihexyphenidyl HCl is indicated as an adjunct in the treatment of all forms of parkinsonism (postencephalitic, arteriosclerotic, and idiopathic). It is often useful as adjuvant therapy when treating these forms of parkinsonism with levodopa. Additionally, it is indicated for the control of extrapyramidal disorders caused by central nervous system drugs such as the dibenzoxazepines, phenothiazines, thioxanthenes, and butyrophenones.

CLINICAL PHARMACOLOGY Trihexyphenidyl HCl exerts a direct inhibitory effect upon the parasympathetic nervous system. It also has a relaxing effect on smooth musculature; exerted both directly upon the muscle tissue itself and indirectly through an inhibitory effect upon the parasympathetic nervous system. Its therapeutic properties are similar to those of atropine although undesirable side effects are ordinarily less frequent and severe than with the latter.

Following administration (5 mg/1 Tablet), Trihexyphenidyl Hydrochloride achieves Approximately 62% to 74% enteral uptake across labeled Trihexyphenidyl Hydrochloride strengths bioavailability and maximum serum exposure occurs 2–3 hours after trihexyphenidyl hydrochloride dosing onset, governed by a Steady-state plasma equilibrium reached over 6–12 hour t½ intervals for Trihexyphenidyl Hydrochloride terminal half-life through predominantly hepatic biotransformation with renal elimination of polar trihexyphenidyl hydrochloride conjugates.

Before initiating Trihexyphenidyl Hydrochloride at 5 mg/1 Tablet, clinical safety checklists rule out contraindications trihexyphenidyl hcl is contraindicated in patients with hypersensitivity to trihexyphenidyl hcl or to any of the tablet ingredients.; trihexyphenidyl hcl is also contraindicated in patients with narrow angle glaucoma.; blindness after long-term use due to narrow angle glaucoma has been reported.. Logged tolerability patterns center on nausea (12.9% of reports), headache (8.6% of reports), dizziness (7.2% of reports).