Linda - When starting on an SSRI like Prozac™ (fluoxetine) it is very common to experience an increase in anxiety and panic attacks. The increase in anxiety/panic attacks is normal and they should begin to lessen in number and severity over the first couple weeks as your body adjusts to the Prozac™.

As for the benzodiazepines, Klonepin™ (clonazepam; CDN is Rivotril™) Xanax™ (alprazolam) and Ativan™ (lorazepam) have a very similar mechanism of action as a result of their binding to the same receptors. In humans benzodiazepines exhibit 4 distinct effects: anxiolytic (or anti-anxiety; anticonvulsant; sedative-hypnotic (or sleep inducing); and muscle relaxant effects. Anxioytic effects are mediated through binding to receptors in the limbic and cortical areas of the brain. Anticonvulsant and sedative-hypnotic effects are mediated by binding to receptors in the brainstem, while muscle relaxant effects are due to their binding to receptors in the spinal cord. Benzodiazepines bind to all of these receptors and when they bind to receptors that we do not want them to we call the resulting actions "side effects".

The receptors that benzodiazepines bind to are called (not surprisingly) benzodiazepine receptors, of which there are two varieties or "sub-types" named BZ-1 and BZ-2. BZ-1 receptor sub-types are most abundant in the cerebellum, which, in part is involved in sleep mechanisms and mediate the sedative-hypnotic and anxiolytic effects of benzodiazepines. BZ-2 receptors sub-types are most commonly found in the hippocampus and basal ganglia which, in part, are involved in memory, motor (movement), sensory, and cognitive (thinking/reasoning/intellectual activity) functions. Thus BZ-2 receptor sub-types are responsible for the muscle relaxation, ataxia (loss of coordination), and cognitive impairments caused by benzodiazepines.

Benzodiazepines work by facilitating the neurotransmitter GABA (gamma-aminobutyric acid), whose primary role is to serve as an inhibitory regulator for other neurotransmitters, such as serotonin, norepinephrine, and dopamine (among others). GABA has a net inhibitory effect on neuron (nerve cell) firing, slowing the signaling from one neuron to the next. Hyperactive neuron firing in limbic and cortical areas of the brain result in anxiety. GABA acting on these overacting neurons slows the firing thus alleviating the anxiety.

Benzodiazepines alter the shape of the "GABA-receptor complex" so that GABA either binds more tightly or more easily to it's receptor. This enhances GABA's effects and leads to a slowing of the overactive neurons that are causing the anxiety and panic attacks.

I know that this is much more than you have asked for, but it does give the rationale behind the following answer to the question of whether you should take Klonepin™ with Ativan™.

All benzodiazepines act at the "GABA-receptor complex" in exactly the same way. Although there is some debate among researchers, there appears to be no major differences in the intrinsic activities of currently available benzodiazepines. Clinical differences (eg. potency, half-life, etc.) are usually explained by pharmacokinetic differences (absorption, distribution, metabolism, and excretion) and the use of dosages that are not equipotent.

Therefore, I would suggest that you should only use either Ativan™ or Klonepin™, but not both. Since the Ativan™ has a faster onset of action (especially the sublingual - under the tongue - form which quickly absorbs directly into the bloodstream through the thin and very vascular membrane under the tongue). The sublingual version begins working within 5 minutes, as opposed to the 20 to 45 minutes onset of action when a tablet is swallowed. Time to relief is a very important factor in treating panic disorder.

On the other hand, Klonepin™ has a longer half-life (the time it takes for 1/2 the drug to be excreted from the body) thus it doesn't need to be taken as often. Klonepin's™ half-life (including active metabolites) is 10 - 80 hours, while Ativan's™ half-life is 10 - 20 hours.

I prefer the Ativan SL™ over Klonepin™ for panic disorder and prefer Klonepin™ over Ativan™ for long term, daily use in anxiety because of Klonepin's™ longer half-life which gives a more consistent blood level, without the peaks and valleys in blood level of the shorter acting Ativan™. Also, you would have to take Ativan™ three or four times daily, as opposed to the once or twice daily dosing of the Klonepin™.

Discuss this with your doctor and see what his/her views are. Your doctor knows your medical history. Also, make sure that you are comfortable with his conclusions. Write down your concerns and take them in with you; it is too hard to remember all your questions in the short time that you are allotted for your appointment. Make sure that your concerns are addressed; the doctor may be the expert on diagnosis and treatment, but you know your body more intimately than he does. It is important that you both come to a concordance that is satisfactory to the both of you.

I hope that this is of some help to you. - Cam