Prescription medications are taken by millions of Americans for mood disorders, high blood pressure, diabetes and other chronic conditions.  But did you know these medication could have the unhealthy and unwanted side effect of weight gain?

Although some medications have this obvious effect, causing people to become extremely hungry, but those which have a more subtle effect on the body can mean a steady weight gain over time that seems like part of natural aging when it is not.  Problematically, it is often times not as simple as switching the prescription.  We have compiled a list of "weight-promoting" and "weight-neutral or weight-loss" drugs by what they are used to treat.  If you are gaining weight and you don’t know why, see if any of you medications make this list:

1.     Antidepressants

Promote weight gain: Paxil (paroxetine), Zoloft (sertraline), amitriptyline (Elavil) and Remeron (mirtazapine).  This is usually the case with older antidepressants.

Weight-neutral or weight-loss: Wellbutrin (bupropion) and Prozac (fluoxetine)

2.     Mood-disorder drugs: Drugs with hormonal effects (e.g. antipsychotics and steroids) are among the biggest culprits in weight gain because they affect the brain and its ability to control appetite.  They can even make you hungrier

Promote weight gain: Clozaril (clozapine), Zyprexa (olanzapine), Risperdal (risperidone), Seroquel (quetiapine), Lithium, valproic acid (Depakote) and carbamazepine (Tegretol).  Zyprexa which is used in schizophrenia and bipolar disorder, can cause a weight gain of 20+ pounds, which can be a big barrier for people in continuing treatment. The big obstacle with these drugs is that once people feel better they may stop taking them.

1. Blood pressure medicines

Promote weight gain: Lopressor (metoprolol), Tenormin (atenolol), Inderal (propranolol), Norvasc (amlodipine) and clonidine (Catapres).  Dietary changes, including increasing fiber content and water intake and lowering calorie density can help counterbalance the effects of these medications.

1. Corticosteroids

Promote weight gain: prednisone and methylprednisolone.  People on corticosteroids often put on extra weight around the body’s trunk.  Sometimes can take them every other day or in smaller doses but there's no real substitute for steroids if you need steroids.

1. Diabetes drugs

Promote weight gain: Actos (pioglitazone), Amaryl (glimepiride) and insulin.  It can be difficult to determine which came first: people who are obese become diabetic, and people who are diabetic have mechanisms that make them less responsive to dietary changes.

Weight-neutral or weight-loss: Byetta (exenatide), Januvia (sitagliptin), Symlin (pramlintide), Precose (acarbose) and metformin (Biguanides)

1. Epilepsy drugs

Promote weight gain: carbamazepine and Neurontin (gabapentin).  Alternatives include Lamictal (lamotrigine), Topamax (topiramate) and Zonegran (zonisamide).

1. Birth control pills: Most birth control medications can cause weight gain

If you believe your medications are causing unnatural weight gain, talk with your doctor to see if any alternative medications are available for your condition.  You should always adhere to the dosage and administration directed by your doctor.