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Biomedical subjects

M Fuqua

Publications and source records attributed to M Fuqua.

4 recordsLinked to original sources
PubMed1992

Therapeutic index of pilocarpine, carbachol, and timolol with nasolacrimal occlusion.

We assessed the effect of nasolacrimal occlusion on the therapeutic index of various antiglaucoma medications in healthy volunteers and patients with glaucoma. Nasolacrimal occlusion used with pilocarpine 2% every 12 hours gave the maximal ocular hypotensive response. Carbachol 1.5% every 12 hours with nasolacrimal occlusion gave the maximal response for this drug. For timolol, nasolacrimal occlusion collapsed the dose-response curve and extended the duration of action. A final trial of carbachol added to timolol with nasolacrimal occlusion showed that timolol 0.25% and carbachol 1.5% every 12 hours gave the maximal response for this combination. Our findings suggest that most of the commercially used ocular hypotensive agents can achieve the same maximal effect with lower concentrations and less frequent administration (never exceeding every 12 hours) than are currently recommended should nasolacrimal occlusion be performed. Furthermore, nasolacrimal occlusion should markedly decrease the systemic absorption of topical ocular drugs and lessen the chance of systemic side effects.

Absorption↗
PubMed1992

Therapeutic index of epinephrine and dipivefrin with nasolacrimal occlusion.

We assessed the effect of nasolacrimal occlusion on the therapeutic index of the adrenoreceptor agonists in healthy volunteers and patients with glaucoma. Nasolacrimal occlusion did not significantly alter the response to 2% epinephrine or to 0.1% dipivefrin in healthy subjects, suggesting that both 2% epinephrine and 0.1% dipivefrin are at the top of the dose-response curve. When 0.5% epinephrine with nasolacrimal occlusion was tested in patients with glaucoma, effects were noticeable at four and eight hours (P less than .05), but not at 12 hours. For 2% epinephrine, there was no significant difference at any measurement time. Epinephrine (1%) with and without nasolacrimal occlusion gave results similar to those of 2% epinephrine, suggesting that 1% epinephrine is also at the top of the dose-response curve. Nasolacrimal occlusion did not increase the ocular hypotensive effect of either of these concentrations. Because dipivefrin, the most widely used formulation in this class, is a prodrug of epinephrine that has a corneal penetration approximately 17 times that of epinephrine, 0.05% dipivefrin, every 12 hours, might be an adequate dosage for maximal effect. Although nasolacrimal occlusion did not alter the drug effect of 0.1% dipivefrin, preventing as much drug as possible from reaching the systemic circulation is desirable.

Absorption↗
PubMed1989

Effect of intracameral carbachol on intraocular pressure after cataract extraction.

Thirty-two patients were randomly assigned to a treatment or a control group to determine the dose-response and duration of action of intracameral carbachol on immediate postoperative intraocular pressure after extracapsular cataract extraction using a viscoelastic substance. Patients in the treatment group received 0.5, 0.25, or 0.1 ml of 0.01% intracameral carbachol. Patients in the control group received 0.1 or 0.5 ml of balanced salt solution. Intraocular pressures of all patients were measured preoperatively and at three, six, 12, 24, and 48 hours postoperatively. The control group as a whole showed a 9.5-mm Hg intraocular pressure rise at three hours, a 10.0-mm Hg rise at six hours, a 9.0-mm Hg rise at 12 hours, and a 7.2-mm Hg rise at 24 hours postoperatively. The group treated with 0.5 ml of carbachol maintained stable intraocular pressures through the 48-hour measurement period. The groups treated with 0.25 and 0.1 ml of carbachol maintained stable intraocular pressures through 24 hours postoperatively. The differences in intraocular pressure were statistically significant for all treated groups through the 24-hour measurement.

Carbachol↗