Is atropine (antimuscarinic) ophthalmic solution 1% intended for sublingual administration?

From the Guidelines

Atropine ophthalmic solution 1% is not intended for sublingual administration, and its use by this route is not recommended due to potential local irritation, unpredictable absorption, and adverse effects. The formulation of atropine ophthalmic solution is specifically designed for eye use, containing preservatives and other ingredients not meant for sublingual administration 1. If sublingual atropine is needed for a medical purpose, a proper systemic formulation of atropine sulfate should be used instead.

The concentration in ophthalmic solutions (1%) is much higher than what would typically be used systemically, which could lead to significant anticholinergic side effects including tachycardia, dry mouth, urinary retention, and confusion if absorbed systemically. According to the most recent evidence, atropine ophthalmic solution 1% is used for treating amblyopia in children, and its administration is limited to the eye 2. Other studies support the use of atropine in ophthalmic formulations for cycloplegic refraction, but do not recommend sublingual administration 3.

In palliative care, atropine may be used sublingually, but this is an exception and not related to the ophthalmic formulation 1. In general, the use of atropine ophthalmic solution 1% sublingually is not recommended due to the potential risks and adverse effects, and alternative formulations should be used when systemic administration is required. Key points to consider include:

• Atropine ophthalmic solution 1% is formulated for eye use only
• Sublingual administration is not recommended due to potential local irritation and adverse effects
• Systemic formulations of atropine sulfate should be used for sublingual administration when needed
• The concentration of atropine in ophthalmic solutions is higher than typically used systemically, increasing the risk of anticholinergic side effects.

From the FDA Drug Label

ATROPINE SULFATE OPHTHALMIC SOLUTION, 1%, for topical ophthalmic use In individuals from three (3) months of age or greater 1 drop topically to the cul-de-sac of the conjunctiva, forty minutes prior to the intended maximal dilation time (2.1)

The FDA drug label does not support the use of atropine (antimuscarinic) ophthalmic solution 1% for sublingual administration. The label specifically states that it is for topical ophthalmic use.

• The recommended administration route is topical to the cul-de-sac of the conjunctiva.
• There is no mention of sublingual administration in the provided drug labels 4 4.

From the Research

Administration of Atropine Ophthalmic Solution

• Atropine 1% ophthalmic solution is not typically intended for sublingual administration, as it is an antimuscarinic medication designed for ophthalmic use 5, 6, 7, 8, 9.
• However, several studies have investigated the use of atropine 1% ophthalmic solution administered sublingually for various purposes, including:
  • Management of terminal respiratory secretions 6, 8
  • Treatment of clozapine-induced sialorrhoea 7
  • As a potential substitute for atropine autoinjectors in the treatment of nerve agent exposure 9
  • Evaluation of systemic bioavailability and pharmacokinetics of sublingual atropine ophthalmic solution 5
• These studies suggest that sublingual administration of atropine 1% ophthalmic solution may be effective and relatively safe for certain indications, but its use for this purpose is not FDA-approved and should be approached with caution 5, 6, 7, 8, 9.