Potentiation of adrenergic effects should be borne in mind when the therapy is prefered in patients on MAOI therapy or upto 21 days, after administration of MAOIs. Either avoid or alter dosage structure in such patients.

Mydriatic effect is increased when PNE is given with other cycloplegic antimuscarinic patients.

The pressor response to phenylephrine may also be potentiated when concomittantly given with tricyclic antidepressants.

Pupillary and pressor response were potentiated when PNE is given in patients on guanethidine therapy, whereas levopa has decreased mydriatic effect.

Prior to ocular surgery, Ophthmological examination

PNE- eye pain, stinging, blurred vision, photophobia, and systemic effects include arrhythimias, hypertension, and coronary artery spasm.

TPM- increased intraocular pressure, (less severe), psychotic reactions, behavioural disturbances and cardiorespiratory collapse. in some children and adults.

Adverse reactions of the combination- lacrimation, tachycardia, palpitation and tremor.

Hyperesensitivity to either agent of the combination

Narrow angle glaucoma

Prior to peripheral iridectomy

Indications:

Opthalmological examination, prior to ocular surgery

Dosage:

Recomended dosage for opthalmological examination- 1-2 drops instilled into the eyes 15-30 minutes prior to procedure

Pharmacology:

Following topical application of PNE , maximum effect sets in within 20-30 minutes and remains for about 4-6 hrs. TPM tends to have greater mydriatic than cycloplegic effect. Maximum mydriatic effect of TPM occurs within 20-30 minutes and lasts for 6-7 hrs, whereas cycloplegic effect occurs for 30-60 mins and has no remaining effect after 2-3 hrs, but complete recovery of accomodation normally within 6 hours. Combination having PNE and anticholinergic drugs, has produced maximal mydriasis lasting several hours

Pharmacokinetics:

Following oral administration of PNE topically through conjuctiva results in systemic absorption which would result in systemic sympathomimetic effects. Ciruculating drug is metabolised in the liver by the enzyme monoamine oxidase. TPM may be systemically absorbed excessively. Excercise caution during the administration.