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Oxybutynin Patches (OXYTROL): A Grossly Overpriced Product For Overactive Bladder

Worst Pills, Best Pills Newsletter article July, 2003

In February of this year the Food and Drug Administration (FDA) approved a transdermal or patch form of the old drug oxybutynin (OXYTROL) for the treatment of overactive bladder. The drug is applied to the skin every three to four days. Oxybutynin has been available in the U.S. since 1976 and there are many less expensive generic versions of the tablet form of the drug on the market.

Transdermal oxybutynin is marketed by Watson Pharma, Inc. of Corona CA. The most common brand name for...

In February of this year the Food and Drug Administration (FDA) approved a transdermal or patch form of the old drug oxybutynin (OXYTROL) for the treatment of overactive bladder. The drug is applied to the skin every three to four days. Oxybutynin has been available in the U.S. since 1976 and there are many less expensive generic versions of the tablet form of the drug on the market.

Transdermal oxybutynin is marketed by Watson Pharma, Inc. of Corona CA. The most common brand name for oral oxybutynin is DITROPAN.

Oxybutynin is referred to as an anticholinergic drug. Anticholinergic drugs block the effects of acetylcholine, a substance produced by the body that is responsible for certain nervous system activities. Drugs with anticholinergic effects (including some antidepressants, antihistamines, antipsychotics, drugs for intestinal problems, antiparkinsonians) inhibit the secretion of acid in the stomach, slow the passage of food through the digestive system, inhibit the production of saliva, sweat, and bronchial secretions, and increase the heart rate and blood pressure. Adverse effects of these drugs include dry mouth, constipation, difficulty urinating, confusion, worsening of glaucoma, blurred vision, and short-term memory problems.

The editors of The Medical Letter on Drugs and Therapeutics, a respected independent source of drug information written for physicians and pharmacists, reviewed transdermal oxybutynin in their May 12, 2003 issue and concluded:

Oxybutynin delivered transdermally may cause less dry mouth than when it is taken orally, but it may also be less effective for incontinence, and itching at the application site can be a problem. As the Medical Letter has said before, none of these drugs are as effective as advertisements to the public have suggested.

We agree with the Medical Letter editors on their assessment of transdermal oxybutynin’s effectiveness and we would characterize this drug’s effectiveness as only marginal. In the first of two clinical trials described in the drug’s professional product labeling or package insert, transdermal oxybutynin was compared to a placebo. At the end of the 12 week study there was an average reduction in incontinence episodes of 21 per week in patients using transdermal oxybutynin. For those patients given the placebo the average reduction was 19.2 per week. This is an average difference of 1.8 episodes of incontinence per week.

When daily urinary frequency was measured the average reduction seen in patients receiving the transdermal oxybutynin was two per day; with the placebo it was one.

In the second clinical trial described in the package insert, patients who had previously responded to an anticholinergic drug for the urinary symptoms were studied for 12 weeks. The average daily reduction in incontinence episodes was 2.9 in the transdermal oxybutynin treated patients. In the placebo group, the average reduction was 2.1 episodes. This is a difference of less than one episode per day on average.

A similar result was found when daily urinary frequency was studied. On average there was only a difference of 0.5 episodes of urinary frequency per day between the transdermal oxybutynin and the placebo.

In the area of retail cost, the difference between transdermal oxybutynin and generic oxybutynin is not marginal, it is significant by almost a factor of ten. A one month supply of eight transdermal oxybutynin patches is $146.99 at a Washington, DC chain pharmacy. At the same pharmacy a one month supply, 90 tablets, of generic oral oxybutynin is $15.09 at the maximum recommended dose of five milligrams, three times a day.

One cause of loss of bladder control is drugs. There are a number of prescription and non-prescription drugs that have been associated with bladder control problems. These drugs are listed in the table on these pages. DO NOT stop taking any of these drugs without first consulting your physician. The drugs are arranged by their family and then in alphabetical order by the most common brand name. This table was constructed from various sources including the medical literature, Side Effects of Drugs Annual 25, 2002, and the Textbook of Adverse Drug Reactions.

What You Can Do

You should check the list of drugs that can cause loss of bladder control before starting drug treatment for this condition. You may be able to change from a drug that causes loss of bladder control to a drug that does not or alter the dose. This may be enough to solve the problem. DO NOT stop taking any of the drugs in the list without consulting your physician.

You should try a low dose of generic oxybutynin tablets before using oxybutynin patches. Neither form of the drug is particularly effective but you can save a significant amount of money by using the generic tablets.

 

WARNING: SPECIAL MENTAL AND PHYSICAL ADVERSE EFFECTS

Older adults are especially sensitive to the harmful anticholinergic effects of drugs such as oxybutynin. Drugs in this family should not be used unless absolutely necessary.

Mental Effects: confusion, delirium, short-term memory problems, disorientation, and impaired attention.

Physical Effects: dry mouth, constipation, difficulty urinating (especially for a man with an enlarged prostate), blurred vision, decreased sweating with increased body temperature, sexual dysfunction, and worsening of glaucoma.

 

 

DRUGS THAT CAN CAUSE LOSS OF BLADDER CONTROL

BRAND NAME

GENERIC NAME

Antibiotics and other anti-infective agents

Urised

atropine/hyoscyamine/methenamine/ methylene blue/phenyl salicylate/benzoic acid

Eye drugs

Betagan

levobunolol

Gastrointestinal drugs          

Cyotec

misoprostol

Heart and blood vessel drugs
High blood pressure drugs (beta-blockers)

Blocadren

timolol

Cartrol

carteolol

Coreg

carvedilol

Corgard

nadolol

Corzide

nadolol/bendroflumethiazide

Inderal, Inderal LA

propranolol

Inderide LA

propranolol/hydrochlorothiazide

Kerlone

betaxolol

Levatol

penbutolol

Lopressor, Toprol XL

metoprolol

Lopressor HCT

metoprolol/hydrochlorothiazide

Normodyne, Trandate

labetalol

Sectral

acebutolol

Tenoretic

atenolol/chlorthalidone

Tenormin

atenolol

Visken

pindolol

Zebeta

bisoprolol

Ziac

bisoprolol/hydrochlorothiazide

High blood pressure drugs (diuretics)

Aldactazide

spironolactone/hydrochlorothiazide

Aldoril

methyldopa/hydrochlorothiazide

Apresazide

hydralazine/hydrochlorothiazide

Bumex

bumetanide

Combipres

clonidine/chlorthalidone

Demadex

torsemide

Diupres

reserpine/chlorothiazide

Diuril

chlorothiazide

Dyazide, Maxzide

triamterene/hydrochlorothiazide

Enduron

methyclothiazide

Enduronyl

deserpidine/methyclothiazide

Esidrix, HydroDiuril

hydrochlorothiazide

Hydropres

reserpine/hydrochlorothiazide

Hygroton

chlorthalidone

Inderide LA

propranolol/hydrochlorothiazide

Lasix

furosemide

Lozol

indapamide

Metahydrin, Naqua

trichlormethiazide

Moduretic

amiloride/hydrochlorothiazide

Regroton, Demi-Regroton

reserpine/chlorthalidone

Salutensin

reserpine/hydroflumethiazide

Ser-Ap-Es

reserpine/hydralazine/hydrochlorothiazide

Tenoretic

atenolol/chlorthalidone

Zaroxolyn, Diulo

metolazone

High blood pressure drugs (other)

Adalat, Adalat CC,
Procardia, Procardia XL

nifedipine

Aldactone

spironolactone

Cardene, Cardene SR

nicardipine

Cardura

doxazosin

DynaCirc, DynaCirc CR

isradipine

Hytrin

terazosin

Minipress

prazosin

Mind-affecting drugs
Antidepressants

Celexa

citalopram

Lexapro

escitalopram

Lithobid, Lithonate

lithium

Luvox

fluvoxamine

Paxil

paroxetine

Prozac

fluoxetine

Wellbutrin

bupropion

Zoloft

sertraline

Antipsychotics

Clozaril

clozapine

Risperdal

risperidone

Zyprexa

olanzapine

Tranquilizers or sleeping pills

Atarax, Vistaril

hydroxyzine

Ativan

lorazepam

BuSpar

buspirone

Centrax

prazepam

Dalmane

flurazepam

Doriden

glutethimide

Halcion

triazolam

Librium

chlordiazepoxide

Miltown, Equanil

meprobamate

Noctec

chloral hydrate

Noludar

methyprylon

Placidyl

ethchlorvynol

Restoril

temazepam

Serax

oxazepam

Tranxene

clorazepate

Valium

diazepam

Xanax

alprazolam

Neurological drugs

Aricept

donepezil

Klonopin

clonazepam

Neutrontin

gabapentin

Other drugs

Zyban

bupropion