New drugs 98: Part III

Nursing, Jun 1998 by Hussar, Daniel A

As with other antipsychotic drugs, use caution in patients with a history of seizures or with conditions that may lower the seizure threshold (for example, Alzheimer's disease). Other possible, although unlikely, adverse reactions include tardive dyskinesia, neuroleptic malignant syndrome, hyperprolactinemia, and disruption of body temperature regulation.

Phenytoin (Dilantin) increases the clearance of quetiapine fivefold, requiring an increase in the new drug's dosage. Many other drugs interact with quetiapine-consult a pharmacist or a comprehensive drug reference for a complete listing.

Quetiapine is available in Canada but not in Australia.

Drug for benign prostatic hyperplasia

TAMSULOSIN HCL

Symptomatic relief for men

Benign prostatic hyperplasia (BPH), characterized by such symptoms as inability to empty the bladder, urinary urgency, frequency, and nocturia, affects an estimated 14 million elderly men in the United States.

Tamsulosin HCI (Flomax, Boehringer Ingelheim) is indicated for treating the signs and symptoms of BPH. It joins finasteride (Proscar) and the alpha^sub 1^-adrenergic-blocking drugs doxazosin (Cardura) and terazosin (Hytrin) as treatment for this disease.

Tamsulosin appears to be as effective as doxazosin and terazosin. Unlike these drugs, however, tamsulosin doesn't significantly lower blood pressure (BP) and isn't indicated for the treatment of hypertension. Tamsulosin provides a useful option for men with BPH who don't have hypertension or who couldn't tolerate a significant decrease in BP.

Patients taking tamsulosin have less risk of orthostatic hypotension than those taking the other alphal-adrenergic-blocking drugs, but some patients may still experience postural hypotension. Advise your patient that this problem may occur, especially at the beginning of therapy. Advise him to get up slowly from a lying position and to avoid activities requiring alertness, such as driving and operating machinery, until he determines how the drug affects him.

One of the most frequent adverse reactions to tamsulosin is abnormal ejaculation, which appears to be dose-related. Other common adverse reactions include rhinitis, asthenia, and back pain.

Tell your patient to take tamsulosin once daily about a half hour after the same meal each day. Warn him not to crush, chew, or open the capsules.

Tamsulosin isn't available in Canada or Australia.

Antihypertensive drug

IRBESARTAN

Theird in its class

Irbesartan (Avapro, Bristol-Myers Squibb; Sanofi) is the third angiotensin II receptor antagonist to be marketed in the United States, joining losartan (Cozaar) and valsartan (Diovan). The new drug is indicated to treat hypertension, either alone or in combination with other antihypertensive drugs.

Adverse reactions include diarrhea, dyspepsia, fatigue, musculoskeletal trauma, and upper respiratory infection. Unlike the angiotensinconverting enzyme inhibitors, irbesartan isn't likely to cause coughing. This represents a significant advantage for irbesartan and the other two angiotensin II receptor antagonists.