Methyldopa Tricyclic antidepressants

Opioids, benzodiazepines, barbiturates, corticosteroids, dopamine agonists (e.g., amantadine, bromocriptine, levodopa, pergolide, pramipexole, ropinirole), H2-receptor antagonists, anticholinergics (e.g., diphenhydramine, trihexylphenidyl), P-adrenergic blockers, clonidine, methyldopa, carbamazepine, phenytoin, baclofen, cyclobenzaprine, lithium, antidepressants (e.g., tricyclic antidepressants, selective serotonin reuptake inhibitors), and interleukin-2... 

Patients taking certain systemic medications are also more sensitive to the pressor effects of phenylephrine. In individuals taking atropine, the pressor effect of phenylephrine is augmented, and tachycardia can occur. Tricyclic antidepressants and monoamine oxidase (MAO) inhibitors also potentiate the cardiovascular effects of topical phenylephrine. The concomitant use of phenylephrine is contraindicated with these agents, even up to 21 days after cessation of MAO inhibitor therapy. Similarly, patients taking reserpine, guanethidine, or methyldopa are at increased risk for adverse pressor effects from topical phenylephrine because of denervation hypersensitivity accompanying the chemical sympathectomy. 

The drug is contraindicated in patients taking MAO inhibitors, tricyclic antidepressants, reserpine, guanethidine, or methyldopa. 

Patients taking monoamine oxidase inhibitors, anticholinergic drugs (such as tricyclic antidepressants), propranolol, reserpine, guanethidine, and methyldopa should be monitored closely if phenylephrine is used (SEDA-16, 542) (16). 

Tricyclic antidepressants reverse the hypotensive effects of postganglionic blocking agents, guanethidine, reser-pine, clonidine, and alpha-methyldopa, and the addition of a tricyclic can result in loss of blood pressure control (159,179). Sudden withdrawal of a tricyclic compound from a patient stabilized with these compounds can also result in serious hypotension. An additional reason for avoiding drugs such as reserpine, methyldopa, and... 

Clinically important, potentially hazardous interactions with antihypertensives, dexamethasone, ephedra, furazolidone, guanethidine, guarana, MAO inhibitors, methyldopa, oxprenolol, phenelzine, phenylpropanolamine, selegiline, tranylcypromine, tricyclic antidepressants... 

Reserpine and imipramine may inhibit the hypotensive action concurrent use of MAO inhibitors augments it (S" ). There is some evidence that the administration of tricyclic antidepressants in combination with a-methyldopa wUl lead to a loss of the hypotensive effect, but certainly not as marked as... 

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