What it's used for
Trihexyphenidyl is used as an adjunct in treating all forms of parkinsonism and for controlling extrapyramidal disorders caused by central nervous system drugs.
Source: U.S. FDA-approved prescribing information (openFDA).
Typical dosing
Dosage should be individualized, starting at a low dose and increasing gradually, especially in patients over 60 years of age.
Dosing shown here is the general FDA-labeled range. Your prescribing clinician determines the exact dose, form, and schedule for you — this is not a substitute for medical advice.
Boxed warning / key safety info
Anticholinergic drugs may precipitate angle closure with an increase in intraocular pressure, so patients should be evaluated prior to therapy.
Common side effects
Minor side effects such as dry mouth, blurred vision, dizziness, mild nausea, or nervousness are experienced by 30 to 50 percent of patients.
Covered strengths on the Tab $0 list
Covered at $0 with an active Tab membership when filled at a participating pharmacy nationwide or through mail order. A licensed clinician must prescribe the medication.
Related medications
Other everything else medications covered at $0 with an active Tab membership.
Trihexyphenidyl cost without insurance
Cash prices for Trihexyphenidyl without insurance vary widely by pharmacy, strength and quantity — the same prescription can cost very different amounts at two pharmacies in the same town. That is the problem a membership solves.
Trihexyphenidyl is on Tab's covered $0 generic list. With an active Tab membership, every covered strength is $0 — not a percentage off, not a coupon that changes month to month — at participating pharmacies nationwide or through mail order. You do not need insurance, and Tab works whether or not you have a health plan.
Tab is a membership, not insurance. Covered medications require a prescription from a licensed clinician.
Trihexyphenidyl dosage and administration
Dosage should be individualized. The initial dose should be low and then increased gradually, especially in patients over 60 years of age.Whether trihexyphenidyl may best be given before or after meals should be determined by the way the patient reacts. Postencephalitic patients, who are usually more prone to excessive salivation, may prefer to take it after meals and may, in addition, require small amounts of atropine which, under such circumstances, is sometimes an effective adjuvant. If trihexyphenidyl tends to dry the mouth excessively, it may be better to take it before meals, unless it causes nausea. If taken after meals, the thirst sometimes induced can be allayed by mint candies, chewing gum or water. Abrupt withdrawal of treatment for parkinsonism may result in acute exacerbation of parkinsonism symptoms;
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Your prescribing clinician decides the exact dose, form and schedule for you — this is not medical advice.
Trihexyphenidyl side effects
Minor side effects, such as dryness of the mouth, blurred vision, dizziness, mild nausea or nervousness, will be experienced by 30 to 50 percent of all patients. These sensations, however, are much less troublesome with trihexyphenidyl than with belladonna alkaloids and are usually less disturbing than unalleviated parkinsonism. Such reactions tend to become less pronounced, and even to disappear, as treatment continues. Even before these reactions have remitted spontaneously, they may often be controlled by careful adjustment of dosage form, amount of drug, or interval between doses.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. This is not a complete list. Report side effects to your clinician, and seek care for anything severe or unexpected.
Trihexyphenidyl drug interactions
Cannabinoids, barbiturates, opiates, and alcohol may have additive effects with trihexyphenidyl, and thus, an abuse potential exists. Concurrent use of alcohol or other CNS depressants with trihexyphenidyl may cause increased sedative effects. Monoamine oxidase inhibitors and tricyclic antidepressants possessing significant anticholinergic activity may intensify the anticholinergic effects of antidyskinetic agents because of the secondary anticholinergic activities of these medications. Prophylactic administration of anticholinergic agents, such as trihexyphenidyl, as a prevention of drug-induced parkinsonism during neuroleptic therapy is not recommended. There may be an increased risk for the development of tardive dyskinesia during concomitant administration of anticholinergics and neuroleptics (See PRECAUTIONS, General ).
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Tell your clinician and pharmacist about every medication, supplement and over-the-counter product you take.
Who should not take trihexyphenidyl
Trihexyphenidyl is contraindicated in patients with hypersensitivity to trihexyphenidyl or to any of the other ingredients. Trihexyphenidyl is also contraindicated in patients with narrow angle glaucoma. Blindness after long-term use due to narrow angle glaucoma has been reported.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Whether this medication is appropriate for you is a clinical decision made by your prescribing clinician.
Common questions
Is trihexyphenidyl covered at $0 with Tab?
Yes. Trihexyphenidyl is on Tab's covered $0 generic list — every covered strength is $0 with an active membership, at participating pharmacies nationwide or by mail order.
Do I need insurance to get trihexyphenidyl through Tab?
No. Tab is a membership, not insurance. Covered medications are $0 with an active membership whether or not you have a health plan.
How do I get a trihexyphenidyl prescription with Tab?
Book a video visit with a licensed Tab clinician (unlimited visits are included with membership). If it's clinically appropriate, they send the prescription to your chosen participating pharmacy or by mail order.
How much does trihexyphenidyl cost without insurance?
Without insurance, retail cash prices for trihexyphenidyl vary by pharmacy, strength and quantity. Trihexyphenidyl is on Tab's covered $0 generic list, so every covered strength is $0 with an active Tab membership at participating pharmacies nationwide or by mail order.
What is the cheapest way to get trihexyphenidyl?
For medications on Tab's covered list, a Tab membership is the cheapest route: covered strengths of trihexyphenidyl are $0 with an active membership, and unlimited video visits with a licensed clinician are included, so the visit that produces the prescription is covered too.
What is the usual dose of trihexyphenidyl?
Dosage should be individualized. The initial dose should be low and then increased gradually, especially in patients over 60 years of age.Whether trihexyphenidyl may best be given before or after meals should be determined by the way the patient reacts. (FDA-approved label, retrieved 2026-09-15. Your clinician sets your dose.)
What are the side effects of trihexyphenidyl?
Minor side effects, such as dryness of the mouth, blurred vision, dizziness, mild nausea or nervousness, will be experienced by 30 to 50 percent of all patients. These sensations, however, are much less troublesome with trihexyphenidyl than with belladonna alkaloids and are usually less disturbing than unalleviated parkinsonism. (FDA-approved label, retrieved 2026-09-15.)
What interacts with trihexyphenidyl?
Cannabinoids, barbiturates, opiates, and alcohol may have additive effects with trihexyphenidyl, and thus, an abuse potential exists. Concurrent use of alcohol or other CNS depressants with trihexyphenidyl may cause increased sedative effects. (FDA-approved label, retrieved 2026-09-15. Tell your clinician about every medication and supplement you take.)
Trihexyphenidyl is $0 on the covered list
Members pay $0 for covered generics at participating pharmacies nationwide or by mail order — plus unlimited virtual primary care, urgent care and dermatology visits. No insurance needed.
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