[leonardo1434]

This may work.

pawn Код:

new bool:works[MAX_PLAYERS],_i = 0,_e,Float:_D[3];
public OnPlayerUpdate(playerid)
{
    if(GetPlayerWeapon(playerid) == 24) // checking if has a deagle
    {
       _e = GetMaxPlayers();
       GetPlayerPos(playerid,_D[0],_D[1],_D[2]);//player pos.
       for(; _i < _e; ++_i) // loop.
       {
          if(IsPlayerInRangeOfPoint(_i,1.0,_D[0],_D[1],_D[2])) // checking if there's players near to him.
          {
             works[playerid] = true; // setting the bool.
          }
       }
    }
    works[playerid] = false; // not near.
    return 1;
}
public OnPlayerTakeDamage(playerid, issuerid, Float: amount, weaponid)
{
    new Float:HP;
    GetPlayerHealth(playerid, HP);
    if(works[playerid]) // if true, it means, he has the wep in his hand's, so it doesn't matter if he punch's or not.
    {
        SetPlayerHealth(playerid, HP-50); // setting his health -50 while is being punched or not.
    }
    return 1;
}